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Tohoku University geophysicist Yuto Katoh led a study into the activity of high energy electrons and clarified the unexpected role of the geomagnetic field surrounding the Earth in protecting.
Understanding the ionosphere high in the Earth's atmosphere is important due to its effects on communications systems, satellites and crucial chemical features including the ozone layer. New insights into the activity of high energy electrons have come from a simulation study led by geophysicist Yuto Katoh at Tohoku University, reported in the journal Earth, Planets and Space.
"Our results clarify the unexpected role of the geomagnetic field surrounding the Earth in protecting the atmosphere from high energy electrons," says Katoh.
The ionosphere is a wide region between roughly 60 and more than 600 kilometers above the Earth's surface. It contains electrically charged particles that are a mixture of ions and free electrons generated by the interaction of the atmosphere with radiation from the sun.
Polar regions of the ionosphere are subjected to a particularly steady and energetic stream of incoming electrons in a process called electron precipitation. These 'relativistic' electrons move at close to the speed of light, where the effects of Einstein's relativity theory become ever more significant. They collide with gas molecules and contribute to many phenomena in the ionosphere, including colourful auroral displays. The processes are heavily influenced by the effects of the geomagnetic field on the charged particles involved.
The Tohoku team, with colleagues in Germany and other institutions in Japan, developed a sophisticated software code that focused particular attention on simulating the effects of a relatively unstudied 'mirror force' on the electron precipitation. This is caused by the magnetic force acting on charged particles under the influence of the geomagnetic field.
The simulations demonstrated how the mirror force causes relativistic electrons to bounce back upwards, to an extent dependent on the angles at which the electrons arrive. The predicted effects mean that electrons collide with other charged particles higher in the ionosphere than previously suspected.
Illustrating one example of the significance of this work, Katoh comments: "Precipitating electrons that manage to pass through the mirror force can reach the middle and lower atmosphere, contributing to chemical reactions related to variations in ozone levels." Decreased ozone levels at the poles caused by atmospheric pollution reduce the protection ozone offers living organisms from ultraviolet radiation.
Katoh emphasizes the key theoretical advance of the research is in revealing the surprising significance of the geomagnetic field and the mirror force in protecting the lower atmosphere from the effects of electron precipitation activities by keeping them further away.
"We have now started a project to combine the simulation studies used in this work with real observations of the polar ionosphere to build even deeper understanding of these crucial geophysical processes," says Katoh.
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Study highlights the young age of permanently shadowed lunar areas
Most of the moon's permanently shadowed areas arose less than 2.2 billion years ago and some trapped ice during the recent past, according to research led by Planetary Science Institute Senior Scientist Norbert Schorghofer.
"These findings change the prediction for where we would expect to find water ice on the moon, and it dramatically changes estimates for how much water ice there is on the moon. Ancient water ice reservoirs are no longer expected," said Schorghofer, lead author of "Past Extent of Lunar Permanently Shadowed Areas," which appears in Science Advances.
Lunar water ice is a component integral to missions to the moon, both to maintain human life and for producing fuel for spacecraft. Permanently shadowed regions (PSRs) are thought to have trapped ices and are a main focus of lunar exploration.
The moon steadily migrates away from Earth, and it feels tidal forces from both the Earth and the sun. It was known for decades that the moon experienced a major spin axis reorientation at some point in the deep past, but there wasn't enough data to really know when. It was only last year that a group in France came up with a coherent history for the evolution of the Earth-moon distance.
"When I heard about their result, I immediately realized it has profound implications for the search of water ice on the moon. I dropped everything I was doing and began to work out the specifics, with the help of my co-author Raluca Rufu," Schorghofer said. "We calculated the lunar spin axis orientation and the extent of PSRs based on recent advances for the time evolution of the Earth-moon distance."
Early in its history, the moon (which is 4.5 billion years old) was bombarded by comets and volcanism released water vapor from its interior, but continuously shadowed areas started to appear only 3.4 billion years ago. By that time these processes had started to die down, so most of the water that was delivered to the moon or outgassed from its interior could not have been trapped in the polar regions. Any ice in the polar regions today must have a more recent origin.
"We have been able to quantify how young the lunar PSRs really are," Schorghofer said. "The average age of PSRs is 1.8 billion years, at most. There are no ancient reservoirs of water ice on the moon."
The impact site of the Lunar Crater Observation and Sensing Satellite, a robotic spacecraft that detected water in 2009, lies within a PSR that is less than 1 billion years old, and therefore all the volatiles discovered there—which include water and carbon dioxide—must be young, he said. In a way this is very encouraging, because even the young PSRs contain ice. Older PSRs should contain even more ice.
This work might also explain why the polar regions of planet Mercury have much more ice than the moon's. Mercury's PSRs are much older and could have captured water early on.
More information: Norbert Schörghofer et al, Past extent of lunar permanently shadowed areas, Science Advances (2023). DOI: 10.1126/sciadv.adh4302
Journal information: Science Advances
Provided by Planetary Science Institute | Chemistry and Material Sciences |
We've discovered how diamonds make their way to the surface and it may tell us where to find them
"A diamond is forever." That iconic slogan, coined for a highly successful advertising campaign in the 1940s, sold the gemstones as a symbol of eternal commitment and unity.
But our new research, carried out by researchers in a variety of countries and published in Nature, suggests that diamonds may be a sign of break up too—of Earth's tectonic plates, that is. It may even provide clues to where is best to go looking for them.
Diamonds, being the hardest naturally-occurring stones, require intense pressures and temperatures to form. These conditions are only achieved deep within the Earth. So how do they get from deep within the Earth, up to the surface?
Diamonds are carried up in molten rocks, or magmas, called kimberlites. Until now, we didn't know what process caused kimberlites to suddenly shoot through the Earth's crust having spent millions, or even billions, of years stowed away under the continents.
Supercontinent cycles
Most geologists agree that the explosive eruptions that unleash diamonds happen in sync with the supercontinent cycle: a recurring pattern of landmass formation and fragmentation that has defined billions of years of Earth's history.
However, the exact mechanisms underlying this relationship are debated. Two main theories have emerged.
One proposes that kimberlite magmas exploit the "wounds" created when the Earth's crust is stretched or when the slabs of solid rock covering the Earth—known as tectonic plates—split up. The other theory involves mantle plumes, colossal upwellings of molten rock from the core-mantle boundary, located about 2,900km beneath the Earth's surface.
Both ideas, however, are not without their problems. Firstly, the main part of the tectonic plate, known as the lithosphere, is incredibly strong and stable. This makes it difficult for fractures to penetrate, enabling magmas to flush through.
In addition, many kimberlites don't display the chemical "flavors" we'd expect to find in rocks derived from mantle plumes.
In contrast, kimberlite formation is thought to involve exceedingly low degrees of mantle rock melting, often less than 1%. So, another mechanism is needed. Our study offers a possible resolution to this longstanding conundrum.
We deployed statistical analysis, including machine learning—an application of artificial intelligence (AI)—to forensically examine the link between continental breakup and kimberlite volcanism. The results of our global study showed the eruptions of most kimberlite volcanoes occurred 20 to 30 million years after the tectonic breakup of Earth's continents.
Furthermore, our regional study targeting the three continents where most kimberlites are found—Africa, South America and North America—supported this finding. It also added a major clue: kimberlite eruptions tend to gradually migrate from the continental edges to the interiors over time at a rate that is uniform across the continents.
This begs the question: what geological process could explain these patterns? To address this question, we employed multiple computer models to capture the complex behavior of continents as they experience stretching, alongside the convective movements within the underlying mantle.
Domino effect
We propose that a domino effect can explain how breakup of the continents eventually leads to formation of kimberlite magma. During rifting, a small region of the continental root—areas of thick rock located under some continents—is disrupted and sinks into the underlying mantle.
Here, we get sinking of colder material and upwelling of hot mantle, causing a process called edge-driven convection. Our models show that this convection triggers a chain of similar flow patterns that migrate beneath the nearby continent.
Our models show that while sweeping along the continental root, these disruptive flows remove a substantial amount of rock, tens of kilometers thick, from the base of the continental plate.
Various other results from our computer models then advance to show that this process can bring together the necessary ingredients in the right amounts to trigger just enough melting to generate gas-rich kimberlites. Once formed, and with great buoyancy provided by carbon dioxide and water, the magma can rise rapidly to the surface carrying its precious cargo.
Finding new diamond deposits
This model doesn't contradict the spatial association between kimberlites and mantle plumes. On the contrary, the breakup of tectonic plates may or may not result from the warming, thinning and weakening of the plate caused by plumes.
However, our research clearly shows that the spatial, time-based and chemical patterns observed in most kimberlite-rich regions can't be adequately explained solely by the presence of plumes.
The processes triggering the eruptions that bring diamonds to the surface appear to be highly systematic. They start on the edges of continents and migrate towards the interior at a relatively uniform rate.
This information could be used to identify the possible locations and timings of past volcanic eruptions tied to this process, offering insights that could enable the discovery of diamond deposits and other rare elements needed for the green energy transition.
If we are to look for new deposits, it's worth bearing in mind that there are currently efforts by campaign groups to try to eliminate from world markets those diamonds that are used to fund wars (conflict diamonds) or those coming from mines with poor conditions for workers.
Diamonds may or may not be forever, but our work shows that new ones have been repeatedly created over long periods in the history of our planet.
More information: Thomas M. Gernon et al, Rift-induced disruption of cratonic keels drives kimberlite volcanism, Nature (2023). DOI: 10.1038/s41586-023-06193-3
Journal information: Nature
Provided by The Conversation | Chemistry and Material Sciences |
A galactic archaeology project has revealed the Milky Way’s neighboring galaxy, Andromeda, has a violent and dramatic history.
An international team of astrophysicists looked at the chemical compositions of stars in Andromeda, which is the closest large galaxy to our own. The goal wasto reconstruct its past. Sure enough, after examining the abundance of elements in Andromeda and considering the fact this galaxy possesses both planetary nebulas — gas and dust blown away from dying low-mass stars — and red giant stars, the researchers concluded that it experienced dramatic and forceful formation.
In fact, the team thinks the creation of the Andromeda galaxy was more turbulent than the origins of the Milky Way. They theorize that Andromeda initially experienced a burst of intense star formation that created the galaxy's foundation, with a secondary period of star birth happening between 2 billion and 4.5 billion years ago.
"Although in many ways Andromeda is similar to our own Milky Way — it's a similarly-sized, spiral disc galaxy — our new research confirms that its history is far more intense and dramatic, with bursts of activity forming stars in abundance, and two distinct eras of star formation," team leader and University of Hertfordshire professor of astrophysics Chiaki Kobayashi said in a statement.
The idea is the second starburst period was triggered when the gas-rich Andromeda collided and merged with another galaxy, also replete with gas, in an event that astronomers call a "wet merger." The influx of gas in such a merger acts as the fuel to kick-start yet more bouts of star formation.
Andromeda isn’t finished clashing with other galaxies
Scientists have long thought that Andromeda experienced collisions and mergers with other galaxies in its past, thanks to the positions and motions of its individual stars, the stars started out in another galaxy.
Further, by looking at the chemical compositions of these stars, the team found two distinct signatures in the disc components of Andromeda. One family of stars appeared to have ten times more oxygen than iron, while the other group appeared to have similar amounts of both elements. This bit adds a new dimension to the understanding of this galaxy’s past, revealing more about the nature of the suggested collision and its effect on Andromeda’s stellar population.
"This is a fantastic example of how galactic archaeology can provide fresh new insights into the history of our universe," Kobayashi added. "By analyzing the chemical abundance in different ages of stars in Andromeda, we can bring to life its history and better understand its origins."
Thus, Andromeda likely has a history of violence — and its future looks to be equally turbulent, with our own galaxy set to become part of its neighbor’s chaotic existence. This is because the Milky Way and Andromeda are currently on a collision course, set to slam into each other in around 4.5 billion years. This titanic collision will give both galaxies a severe makeover, wiping out the distinctive arms of both spiral galaxies.
The stellar population of the Milky Way and Andromeda, which is currently about 2.5 billion light years away from us, will not slam into each other but will survive to be thrown into new orbits around a new galactic center. Our own star, the sun, and the entire solar system are likely to be pushed away from the new galactic core, moving toward the outskirts of the resultant new galaxy.
The team’s findings add to Kobayashi’s continuing investigation of the origins of the chemical elements throughout the cosmos.
"Oxygen is one of the so-called alpha-elements produced by massive stars. The others are neon, magnesium, silicon, sulfur, argon, and calcium," she explained. "Oxygen and argon have been measured with planetary nebulae, but Andromeda is so far away that the James Webb Space Telescope (JWST) is required to measure other elements, including iron.
"In coming years, JWST and ground-based large telescopes will keep looking at Andromeda — giving further weight to the new findings."
The team’s work was published Oct. 10 in The Astrophysical Journal Letters. | Chemistry and Material Sciences |
Salts and organics observed on Ganymede's surface by NASA's Juno
Data collected by NASA's Juno mission indicates a briny past may be bubbling to the surface on Jupiter's largest moon.
NASA's Juno mission has observed mineral salts and organic compounds on the surface of Jupiter's moon Ganymede. Data for this discovery was collected by the Jovian InfraRed Auroral Mapper (JIRAM) spectrometer aboard the spacecraft during a close flyby of the icy moon.
The findings, which could help scientists better understand the origin of Ganymede and the composition of its deep ocean, were published on Oct. 30 in the journal Nature Astronomy.
Larger than the planet Mercury, Ganymede is the biggest of Jupiter's moons and has long been of great interest to scientists due to the vast internal ocean of water hidden beneath its icy crust. Previous spectroscopic observations by NASA's Galileo spacecraft and Hubble Space Telescope as well as the European Southern Observatory's Very Large Telescope hinted at the presence of salts and organics, but the spatial resolution of those observations was too low to make a determination.
On June 7, 2021, Juno flew over Ganymede at a minimum altitude of 650 miles (1,046 kilometers). Shortly after the time of closest approach, the JIRAM instrument acquired infrared images and infrared spectra (essentially the chemical fingerprints of materials, based on how they reflect light) of the moon's surface.
Built by the Italian Space Agency, Agenzia Spaziale Italiana, JIRAM was designed to capture the infrared light (invisible to the naked eye) that emerges from deep inside Jupiter, probing the weather layer down to 30 to 45 miles (50 to 70 kilometers) below the gas giant's cloud tops. The instrument has also been used to offer insights into the terrain of moons Io, Europa, Ganymede, and Callisto (known collectively as the Galilean moons for their discoverer, Galileo).
The JIRAM data of Ganymede obtained during the flyby achieved an unprecedented spatial resolution for infrared spectroscopy—better than 0.62 miles (1 kilometer) per pixel. With it, Juno scientists were able to detect and analyze the unique spectral features of non-water-ice materials, including hydrated sodium chloride, ammonium chloride, sodium bicarbonate, and possibly aliphatic aldehydes.
"The presence of ammoniated salts suggests that Ganymede may have accumulated materials cold enough to condense ammonia during its formation," said Federico Tosi, a Juno co-investigator from Italy's National Institute for Astrophysics in Rome and lead author of the paper. "The carbonate salts could be remnants of carbon dioxide-rich ices."
Exploring Other Jovian Worlds
Previous modeling of Ganymede's magnetic field determined the moon's equatorial region, up to a latitude of about 40 degrees, is shielded from the energetic electron and heavy ion bombardment created by Jupiter's hellish magnetic field. The presence of such particle fluxes is well known to negatively impact salts and organics.
During the June 2021 flyby, JIRAM covered a narrow range of latitudes (10 degrees north to 30 degrees north) and a broader range of longitudes (minus 35 degrees east to 40 degrees east) in the Jupiter-facing hemisphere.
"We found the greatest abundance of salts and organics in the dark and bright terrains at latitudes protected by the magnetic field," said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio. "This suggests we are seeing the remnants of a deep ocean brine that reached the surface of this frozen world."
Ganymede is not the only Jovian world Juno has flown by. The moon Europa, thought to harbor an ocean under its icy crust, also came under Juno's gaze, first in October 2021 and then in September 2022. Now Io is receiving the flyby treatment.
The next close approach to that volcano-festooned world is scheduled for Dec. 30, when the spacecraft will come within 932 miles (1,500 kilometers) of Io's surface.
More information: Federico Tosi et al, Salts and organics on Ganymede's surface observed by the JIRAM spectrometer onboard Juno, Nature Astronomy (2023). DOI: 10.1038/s41550-023-02107-5
Journal information: Nature Astronomy
Provided by NASA | Chemistry and Material Sciences |
Scientists may have finally figured out why Earth's precious metals appear close to the surface, despite being so dense they should have sunk to the core. Turns out, they got stuck in gooey, half-melted rock after giant space rocks — some, perhaps, as large as the moon — smashed into Earth.
The abundance of precious metals near the surface has long puzzled researchers. Your platinum engagement ring, your grandmother's antique gold locket, the palladium that makes your car's catalytic converter work: None of them should exist.
Chemically speaking, all of these metals appear in too-large abundances on Earth, leading researchers to believe that they likely landed here during impacts with giant space rocks soon after Earth's formation. Even so, they should have sunk into Earth's core after crash-landing.
Now, in a new study, researchers have a solution to this conundrum: Despite their density, these metals can percolate through the mantle and become trapped in solidifying rock, keeping them close enough that they can eventually make their way back to Earth's surface. They may even be the reason for mysterious blobs called low-velocity shear zones that are found very deep in the mantle.
"As a result of these impacts, we can produce these large-scale regions that are slightly denser than surrounding material," study co-author Simone Marchi, a researcher at the Southwest Research Institute in Boulder, Colorado, told Live Science.
Gold, platinum, palladium, other platinum-group metals and the transition metal rhenium are all what scientists call "highly siderophile elements." This means they bind easily to iron. If, as scientists believe, these metals were carried to Earth via asteroids and planetoids in the chaos of the young solar system, they should have smashed through the crust and into the mantle, then sunk like a pebble hitting a pond until they reached the iron-rich core.
That didn't happen. To find out why, Marchi and his co-author, geophysicist Jun Korenaga of Yale University, created simulations of these ancient impacts on the early Earth. They first discovered that getting these metals to stay away from the core was even harder than they'd expected.
"In the past, people had been glossing over this idea, [thinking] there has to be a way," Marchi said. "People didn’t really realize that the problem was so severe."
However, their simulations also revealed a solution to this problem. When an enormous space rock — perhaps close to the size of the moon — hit the early Earth, the collision would have obliterated the impactor and created an ocean of melty magma permeating deep into the mantle.
Under this magma ocean, though, would be a boundary area of half-melted, half-solid rock. The metals from the impactor would gradually percolate into this half-molten region, spreading them around. Instead of very dense pure metal that would sink directly toward the core, this region of metal-infused mantle would be only slightly denser than its surroundings. As it slowly sank into higher-pressure regions, it would solidify, trapping small fragments of metal before they could reach the core. Marchi and Korenaga reported their findings Oct. 9 in the journal Proceedings of the National Academy of Sciences.
From there, billions of years of churning and convection in the mantle brings the trapped metals to the crust, within reach of human mining operations. Voila — the materials needed for jewelry and electronics are now conveniently located.
It's possible these metal-rich blobs of mantle are still visible today in images of the mantle that scientists reconstruct from earthquake waves. Large low-velocity shear provinces, or LLSVPs, are areas of the mantle where shear waves from earthquakes move oddly slowly. It's evident there is some difference in the mantle rock in these regions, Marchi said, but scientists aren't sure what.
One possibility is that the difference is in the density, and that LLSVPs are the remnants of the ancient impacts that brought gold, platinum, and other metals to Earth.
One next step, Marchi said, might be to simulate similar impacts on a young Mars or Venus. "Those planets are very different from Earth," he said. "So it might be interesting and important to see how this process would work for these other terrestrial planets."
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Stephanie Pappas is a contributing writer for Live Science, covering topics ranging from geoscience to archaeology to the human brain and behavior. She was previously a senior writer for Live Science but is now a freelancer based in Denver, Colorado, and regularly contributes to Scientific American and The Monitor, the monthly magazine of the American Psychological Association. Stephanie received a bachelor's degree in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz. | Chemistry and Material Sciences |
Scientists have made an exciting and potentially ground-breaking discovery in the search for alien life, after detecting signs of a gas produced only by living organisms on a distant water planet.
K2-18 b, which is more than eight times the size of Earth and 120 light-years away from us, sits within the habitable zone of its cool dwarf star in the Leo constellation.
It is thought to be a 'Hycean' world — a relatively new class of exoplanet possessing key ingredients for alien species because of their hydrogen-rich atmospheres and oceans of water.
But it is the presence of something else that has got astronomers even more excited.
A gas 'uniquely associated with life' when found on Earth has been discovered in the atmosphere of K2-18 b, which is known as a 'super Earth' because it is bigger than our planet but smaller than Neptune.
Many of the prime Hycean candidates previously identified by researchers are bigger and hotter than Earth. However, they still have the characteristics to host large oceans that could support microbial life. This is similar to the forms of life that are found in some of Earth's most extreme aquatic environments. The planets also allow for a far wider habitable zone, or 'Goldilocks zone', compared to Earth-like planets. This means that they could still support life even though they lie outside the range where a planet similar to Earth would need to be in order to be habitable. The vast majority are planets between the sizes of Earth and Neptune and are often referred to as 'super Earths' or 'mini-Neptunes'. They can be predominantly rocky or ice giants with hydrogen-rich atmospheres. Most mini-Neptunes are over 1.6 times the size of Earth: smaller than Neptune but too big to have rocky interiors. Hycean planets can be up to 2.6 times larger than Earth and have atmospheric temperatures up to nearly 200 degrees Celsius (392F).
The compound dimethyl sulphide (DMS) – a complex molecule made up of carbon, hydrogen and sulphur atoms – was detected alongside two carbon-carrying gases, leaving researchers feeling a 'a mix of shock and excitement and disbelief'.
'On Earth, this is only produced by life,' NASA said.
'The bulk of the DMS in Earth's atmosphere is emitted from phytoplankton in marine environments.'
Despite the excitement, scientists have stressed that more observations by the James Webb Space Telescope will be needed to confirm the presence of DMS.
If the discovery is validated it would make K2-18b among the most likely worlds where alien life could exist, alongside the likes of Mars and the icy moons of Jupiter and Saturn in our own solar system.
The super Earth was also found to have large amounts of carbon dioxide and methane in its atmosphere, the presence of which could suggest it is habitable or possibly even inhabited already.
This certainly points to K2-18b being a 'Hycean' world, but because both gases can be produced by inorganic process they don't offer proof of alien life on their own.
Lead author of the research, Nikku Madhusudhan, said even the prospect of DMS existing on a faraway exoplanet was 'mind-boggling'.
The University of Cambridge professor added: 'Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations.
'Upcoming Webb observations should be able to confirm if DMS is indeed present in the atmosphere of K2-18 b at significant levels.'
NASA's $10 billion (£7.4 billion) observatory is able to analyse the chemical make-up of a distant planet by capturing the light from its host star after it has passed through the planet's atmosphere on its way to Earth.
Gases in the atmosphere absorb some of the starlight but each leave tell-tale signatures in the spectrum of light that astronomers can then unpick.
As well as being known as a super Earth, K2-18b is also classified as a 'sub-Neptune' planet.
These worlds are not found in our solar system but are defined as any planet that has a smaller radius than the ice giant that is furthest from our sun.
Sub-Neptunes are poorly understood because of their distance from us, so the nature of their atmospheres is a matter of debate among astronomers.
'Although this kind of planet does not exist in our solar system, sub-Neptunes are the most common type of planet known so far in the galaxy,' said researcher Subhajit Sarkar of Cardiff University.
'We have obtained the most detailed spectrum of a habitable-zone sub-Neptune to date, and this allowed us to work out the molecules that exist in its atmosphere.'
K2-18b's large size – with a radius 2.6 times the radius of Earth – means that the planet's interior likely contains a large mantle of high-pressure ice, like Neptune, but with a thinner hydrogen-rich atmosphere and an ocean surface.
Although Hycean worlds are predicted to be covered in water, researchers say it is also possible that the ocean is too hot to be habitable or be liquid.
Since the first exoplanet was discovered 30 years ago, thousands of others have been spotted outside of our solar system.
The majority are planets between the sizes of Earth and Neptune, often referred to as super Earths, mini-Neptunes or sub-Neptunes.
They can be predominantly rocky or ice giants with hydrogen-rich atmospheres, or something in between.
Earlier studies of such planets found that the pressure and temperature beneath their hydrogen-rich atmospheres would be too high to support life.
But in 2021, research found that in certain conditions the worlds could support life.
Alongside confirming whether DMS is present on K2-18b, researchers will now look for other biomarkers such as methyl chloride that are uniquely created by life.
If they are, it would generate great excitement and thrust the world to the front of the queue in the hunt for alien species.
The new study will appear in The Astrophysical Journal Letters. | Chemistry and Material Sciences |
We’ve all been there: You’re getting some peanut butter, or looking to nosh a nice pickle, when you find your wrist strength is insufficient to get at the jar’s delicious contents. That’s more or less NASA’s vexing issue with the OSIRIS-REx asteroid samples—though, of course, that canister’s contents aren’t for eating.
That’s right. NASA was able to launch a $1.16 billion mission to an asteroid 200 million miles from Earth, retrieve crumbly bits of space rock, and bring them all the way back to our humble habitable world. And now it can’t open the jar. Specifically, two fasteners on TAGSAM (Touch-and-Go Sample Acquisition Mechanism) are refusing to yield to the currently available tools. Scientists hope the samples asteroid Bennu could hold clues to the formation of the solar system and the origins of life, so they’re understandably eager to get things moving.
Luckily, the outside of the sample canister itself was covered in an abundance of asteroid material, meaning some science has already begun. In a press conference last month, OSIRIS-REx sample analyst Daniel Glavin described the asteroid bits as “an astrobiologist’s dream.” They’ve already identified carbon and water molecules.
Gizmodo reached out to several astrobiologists to discuss what exactly they hope to learn from a full analysis of the ancient asteroid material. Here’s what they had to say.
“The OSIRIS-REx samples could help us to find out, if besides the supposed delivery of water on the primordial Earth by comets, this could also be realized by asteroids,” said Jean-Pierre de Vera, an astrobiologist at the German Aerospace Center and President of the European Astrobiology Network Association (EANA), in an email to Gizmodo. “The question still remains on the amount of organics in these rocks which could be delivered on Earth and might have served as the first building blocks of life.”
Whenever meteorites are found on Earth, they offer scientists an opportunity to investigate the origins of the solar system. Many of these rocky bits are carbonaceous chondrites, a class of ancient carbon-bearing meteorites that contain building blocks for life and show signs of aqueous alteration—changes to their structure due to liquid water. As such, they offer an intimate window into how our solar system formed and gave rise to a world like Earth—rich with plate tectonics, covered in oceans, and crowded with living things.
But meteorites that land on Earth are immediately contaminated by, well, Earth. Thanks to the OSIRIS-REx team’s painstaking effort, scientists finally have access to asteroid samples untainted by the vast amount of organic material and alteration that comes with burning up in our planet’s atmosphere and hitting the surface, be it land or sea.
“For the first time we will be able to measure the abundances of all 20 protein-forming amino acids from an asteroid sample untouched by life on Earth,” said Sawsan Wehbi, an astrobiologist at the University of Arizona, in an email to Gizmodo. “My goal is to compare the amino acids we find on Bennu to Earth’s early life. I’m hoping to answer this question: Did early life use the building blocks that were delivered from outer space?”
Whether the samples suggest that ingredients for life processes came from space or may have come from Earth itself, Wehbi said that “I think what we find will fundamentally change our perspective on how we think about life in a cosmological context.”
Bennu is named for an Ancient Egyptian deity associated with rebirth that is the living symbol of the god Osiris, who was himself brought back to life in Egyptian myth. It is a primitive asteroid, dating to the first 10-million-or-so years of the solar system’s existence. As such, scientists believe the asteroid could hold secrets of what the earliest stages of solar system formation could look like, as well as what primordial organic components—to lean on an old cliché, the “building blocks for life”—might exist on the rocky body.
But it’s not quite as simple as that. Bennu underwent some changes in its early existence, which means that scientists will be able to see more than just “building blocks”—they’ll be able to see the game plan an evolving Bennu was following.
“This is sort of a fossil snapshot of some of the most primitive material in the solar system,” said Michael Wong, an astrobiologist at Carnegie Science, in a phone call with Gizmodo. “But a little bit of time elapsed between its formation and where it essentially froze out and stopped evolving as a planetary body.”
“Trying to understand how much chemical complexification has occurred in that brief snapshot of time between when Bennu formed and when Bennu froze and stopped evolving is really interesting to me because it shows you the power of a little bit of rock, a little bit of ice and a little bit of organic matter,” Wong added.
Whatever the chemical cocktail, Bennu may clue us into the ingredients. But just as important as the ingredients are the actual cooking instructions, and the asteroid’s brief period of evolution may help us there too.
“The process of the origin of life is still such a mystery to us and I don’t think the answer is in the exact identities of the molecules,” Wong said. That’s why the ‘building blocks’ term kind of irks me. It’s more about the processes that those molecules are excited to do together. And it may be that the processes of life can arise in very different suites of building blocks.”
Today, Bennu asteroid samples became available for public viewing at the Smithsonian’s National Museum of Natural History in Washington, D.C. So even if analysis of the rocks takes a while to be published, you can ruminate on the origins of life on Earth as soon as you like. | Chemistry and Material Sciences |
A scientist recently claimed that NASA may have inadvertently discovered life on Mars almost 50 years ago and then accidentally killed it before realizing what it was. But other experts are split on whether the new claims are a far-fetched fantasy or an intriguing possible explanation for some puzzling past experiments.
After landing on the Red Planet in 1976, NASA's Viking landers may have sampled tiny, dry-resistant life-forms hiding inside Martian rocks, Dirk Schulze-Makuch, an astrobiologist at Technical University Berlin, suggested in a June 27 article for Big Think.
If these extreme life-forms did and continue to exist, the experiments carried out by the landers may have killed them before they were identified, because the tests would have "overwhelmed these potential microbes," Schulze-Makuch wrote.
This is "a suggestion that some people surely will find provocative," Schulze-Makuch said. But similar microbes do live on Earth and could hypothetically live on the Red Planet, so they can't be discounted, he added.
However, other scientists believe the Viking results are far less ambiguous than Schulze-Makuch and others make them out to be.
Viking experiments
Each of the Viking landers — Viking 1 and Viking 2 — carried out four experiments on Mars: the gas chromatograph mass spectrometer (GCMS) experiment, which looked for organic, or carbon-containing, compounds in Martian soil; the labeled release experiment, which tested for metabolism by adding radioactively traced nutrients to the soil; the pyrolytic release experiment, which tested for carbon fixation by potential photosynthetic organisms; and the gas exchange experiment, which tested for metabolism by monitoring how gases that are known to be key to life (such as oxygen, carbon dioxide and nitrogen) changed surrounding isolated soil samples.
The results of the Viking experiments were confusing, and have continued to perplex some scientists ever since. The labeled release and pyrolytic release experiments produced some results that supported the idea of life on Mars: In both experiments, small changes in the concentrations of some gases hinted that some sort of metabolism was taking place.
The GCMS also found some traces of chlorinated organic compounds, but at the time, mission scientists believed the compounds were contamination from cleaning products used on Earth. (Subsequent landers and rovers have since proved that these organic compounds occur naturally on Mars.)
However, the gas exchange experiment, which was deemed the most important of the four, produced a negative result, leading most scientists to eventually conclude that the Viking experiments did not detect Martian life.
And in 2007, NASA's Phoenix lander, the successor to the Viking landers, found traces of perchlorate — a chemical that's used in fireworks, road flares and explosives, and naturally occurs inside some rocks — on Mars.
The general scientific consensus is that the presence of perchlorate and its byproducts can adequately explain the gases detected in the original Viking results, which has essentially "resolved the Viking dilemma," Chris McKay, an astrobiologist at NASA's Ames Research Center in California, told Live Science in an email.
But Schulze-Makuch believes most of the experiments may have produced skewed results because they used too much water. (The labeled release, pyrolytic release and gas exchange experiments all involved adding water to the soil.)
Too much of a good thing
"Since Earth is a water planet, it seemed reasonable that adding water might coax life to show itself in the extremely dry Martian environment," Schulze-Makuch wrote. "In hindsight, it is possible that approach was too much of a good thing."
In very dry Earth environments, such as the Atacama Desert in Chile, there are extreme microbes that can thrive by hiding in hygroscopic rocks, which are extremely salty and draw in tiny amounts of water from the air surrounding them. These rocks are present on Mars, which does have some level of humidity that could hypothetically sustain such microbes. If these microbes also contained hydrogen peroxide, a chemical that is compatible with some life-forms on Earth, it would help them to further draw in moisture and also may have produced some of the gases detected in the labeled release experiment, Schulze-Makuch proposed.
But too much water can be deadly to these tiny organisms. In a 2018 study published in the journal Scientific Reports, researchers found that extreme floods in the Atacama Desert had killed up to 85% of indigenous microbes that could not adapt to wetter conditions.
Therefore, adding water to any potential microbes in the Viking soil samples may have been equivalent to stranding humans in the middle of an ocean: Both need water to survive, but in the wrong concentrations, it can be deadly to them, Schulze-Makuch wrote.
Alberto Fairén, an astrobiologist at Cornell University and co-author of the 2018 study, told Live Science in an email that he "totally agrees" that adding water to the Viking experiments could have killed potential hygroscopic microbes and given rise to Viking's contradictory results.
Controversial claim
This is not the first time that scientists have proposed that the Viking experiments may have inadvertently killed Martian microbes. In 2018, another group of researchers proposed that when soil samples were heated up, an unexpected chemical reaction could have burned and killed any microbes living in the samples. This group claims that this could also explain some of the puzzling results from the experiments.
However, as McKay suggested, scientists who continue to chip away at the landers' results are wasting their efforts. "I disagree with their logic," he said. "There is no need to invoke a strange new type of life to explain the Viking results."
This article was provided by LiveScience. | Chemistry and Material Sciences |
In October 2020, NASA's OSIRIS-REx spacecraft approached the asteroid Bennu. The probe, which had been orbiting its target for nearly two years, lowered a robotic arm and scooped up about 4.4 pounds (2 kilograms) of dusty, rocky material from the asteroid's surface. This material is the first sample of an asteroid collected by a U.S. mission, and it might help scientists answer some puzzling questions: How old are asteroids like Bennu? And how long do they last?
To understand how long asteroids last, it's crucial to know when and how they formed. The asteroids in our solar system coalesced out of the protoplanetary disk, a thick collection of dust and rocky material that swirled around our sun 4.5 billion years ago.
"The dust began to coagulate," said Harold Connolly, an astronomer at Rowan University in New Jersey and a mission sample scientist for OSIRIS-REx. Over time, these dust bunnies collected more and more material, collided with one another and stuck together. Some of them snowballed into whole planets, like Earth. Others became moons, comets and asteroids.
Most of the asteroids in the solar system now reside in the asteroid belt, which stretches between Mars and Jupiter, though occasionally some get ejected from the belt and become near-Earth asteroids. The largest intact asteroids are roughly the same age as the solar system: 4.5 billion years old. But some asteroids can be considered younger, since they consist of smaller pieces that broke off from these larger bodies.
How do asteroids die?
Asteroids can break up and eventually get destroyed in a few different ways. One is by spinning. Asteroids are usually irregularly shaped — unlike planets, which have enough gravity to pull themselves into a rough sphere — and so they tend to list to one side. If they start to spin after a collision or from being pushed by solar radiation, the force can send chunks of asteroid flying off into space. "You get a little difference in torque here and there, and eventually it falls apart," Connolly said.
Asteroids can also fragment from thermal stress, which is caused when their materials expand and contract in the sun's heat for millions of years, or when they experience sudden water loss as ice inside the asteroid is converted into gas by our star's warmth.
Sometimes, asteroids break up from collisions with other rocky celestial objects, "kind of like a cosmic billiards game," Connolly told Live Science. Based on the probability of breakup, "a 1 kilometer [0.6 mile] thing can survive about 440 million years, [and] a 10 kilometer [6.2 miles] object around 4 billion years" in the asteroid belt, Kevin Walsh, an astronomer at the Southwest Research Institute in Colorado, told Live Science in an email.
Scientists are still working to determine how long the largest asteroids can last, but it's possible that some may endure as long as the rocky inner planets of the solar system do — between 8 billion and 10 billion years. (In approximately 5 billion years, when the sun is around 10 billion years old, our star is expected to burn out and swallow up its neighbors, including planets and asteroids.)
Once an asteroid fragments into small enough pieces, its tiny bits no longer count as an asteroid — a chunk of space debris smaller than 3.2 feet (1 meter) is technically reclassified as a meteoroid, according to NASA. At this point, those meteoroid fragments may collide with a larger body, leaving an impact crater. Or they may cross paths with a planet that has an atmosphere, such as Earth, and become meteors streaking across the sky.
The pieces may also come back together and form what's known as a rubble pile asteroid. These composite bodies get "a second life, in a smaller fragmented version of the initial asteroid," Fred Jourdan, a geochronologist at Curtin University in Australia, told Live Science.
The various bits and pieces are held together with nothing more than their own gravity acting as glue. "It is literally a big pile of rocks with a lot of empty space," Walsh said.
That may seem like a tenuous connection, but these asteroids are tougher than they sound: The space between their pieces acts like shock absorbers against collisions. "Their particular structure makes them almost indestructible," Jourdan said, unless they crash into a planet or fall into the sun. Most near-Earth asteroids, including Bennu, are rubble pile asteroids.
When the samples from Bennu reach Earth this fall, their structure will give astronomers an even better idea of when the rubble pile's components broke off from their parent bodies and how they came back together. "It's going to be a lot of fun," Connolly said. | Chemistry and Material Sciences |
Mars has a heavy heart after all.
The Red Planet has a dense core of liquid iron surrounded by a relatively thin layer of molten rock, researchers report. The finding resolves a recent conundrum that came about when seismic measurements on Mars seemed to suggest that the planet had a surprisingly large, light core rich in low-density elements (SN: 4/24/23).
The new view, described in two studies in the Oct. 26 Nature, shows the planet is made of materials common in the solar system at the time Mars formed. A lighter core would have required a mix of elements that wouldn’t have matched the proportions in the dust and debris that eventually became the solar system.
The researchers deduced the structure of Mars’ interior by studying seismic waves detected with NASA’s InSight lander (SN: 2/24/20). It measured Marsquakes and reverberations from meteorite impacts on the planet for a little over four years.
Waves reflecting from the molten rock layer were initially interpreted as bouncing from the outer edge of a core with a radius of about 1,800 kilometers and a density of 6,200 kilograms per cubic meter. The new research added data from seismic waves that dip into that molten layer to reveal the planet’s true heart.
The core has a roughly 10 percent smaller radius and a higher density than previously reported, with one group finding a density of 6,650 kilograms per cubic meter, and the other finding 6,500 kilograms per cubic meter.
A better understanding of Mars has implications far beyond the Red Planet. Mars and Earth were very similar when they first formed, says planetary scientist Henri Samuel of CNRS in Paris, and a coauthor of one of the new studies. “However, at some point these two planets diverged and Mars is now not habitable while the Earth is. Therefore, understanding how this divergence has occurred can tell us a lot [about] our own planet.” | Chemistry and Material Sciences |
An Archive of the Stars Is Born
Last month, a capsule aboard NASA’s OSIRIS-REx spacecraft finished a seven-year, 4 billion-mile journey from Earth to the asteroid Bennu and back, when it plummeted in a fiery descent to the Utah desert. Inside lay cradled about a half-pound of rubble captured from Bennu—the United States’ first successful mission to return material from an asteroid, and only the third in the world. Soon, small samples will be parceled out to more than 200 scientists at institutions around the globe, who will perform myriad chemical analyses in years to come. These studies may among other things help unravel the mysteries of how the Solar System, and our own planet, were born and evolved.
Like other NASA-curated extraterrestrial materials including meteorites, Moon rocks and cosmic dust, the Bennu samples will generate huge amounts of data. But in recent years, NASA has recognized a big problem: for a long time, there was no central home for all this data, with the results of analyses scattered across the globe at labs, universities and institutes that did the testing. Much of this data has not been easily accessible, and in some cases, has been lost. So the agency decided to create such a home, at the Astromaterials Data System, based at Columbia University’s Lamont-Doherty Earth Observatory.
Astromat, for short, has been tasked by NASA with tracking down, cataloging, digitizing, preserving and making easily accessible and searchable geochemical data from all past, current and future NASA missions, along with some other material. This includes the 1969-1972 Apollo missions to the moon; the Stardust and Genesis missions, which returned particles of the solar wind in 2004, and castoffs from the tail of a comet in 2006, respectively; tiny space particles glommed onto Earth-orbiting craft or special high-flying planes; some 22,000 meteorites collected in Antarctica; and some data from Japan’s 2010 Hayabusa mission, the first to return asteroid material to Earth. Future projects include NASA’s Artemis mission, aimed at collecting more material from the Moon within the next decade, and the planned return of samples from Mars, in the 2040s.
“This will preserve the data for future generations, and create new opportunities to study it and build new insights,” said mineralogist Kerstin Lehnert, who directs the project as head of the Lamont Geoinformatics Research Group. “It’s also about democratizing science. Before this, only a small, insular community had access to a lot of this data. Now, everything will be available to anyone with a computer and access to the Internet.”
The project is something of an outgrowth of Earthchem, a vast database of geochemical analyses of materials from the Earth itself that the group has run since 2006. The extraterrestrial project began in 2014, when they worked with NASA to build a database of analyses acquired from the Apollo missions. Starting in 2019, the system was upgraded so it could begin archiving data derived from all of NASA’s materials. Data from most post-Apollo missions was made available this year. In August, NASA budgeted $10 million to run the system over the next five years, with the data to be stored on the NASA Mission Cloud Platform, based at the Goddard Space Flight Center in Maryland. The grant also supports engagement with the astromaterials community to encourage data sharing.
The system currently contains the results of nearly 1.3 million separate chemical analyses. This number will grow quickly with the OSIRIS-REx mission, and the recent release to researchers of a new batch of yet-untouched Moon material that NASA had kept stockpiled. With scientists now able to view and compare all the data from thousands of separate studies, new knowledge is emerging from old information. This year, a group of meteorite specialists and data scientists used machine learning to pick through data, which enabled them to understand the origins of some previously uncategorizable meteorites.
Lehnert said that finding data and converting it to uniform, usable form has been a long process. Initially, the 10-person team had to sift through the scientific literature and figure out what findings had been published; there was no central record. The most recent studies made the data available in digital supplements, but earlier ones from times before this technology became standard did not. For these, the team had to contact study authors for records. Furthermore, many analyses remained unpublished, mentioned only in abstracts presented at scientific conferences, or not presented at all; this required even more legwork.
The further back they went, the harder it was to recover data stored on floppy disks or other outmoded media in antique computer languages, along with piles of computer printouts, typescripts or plain old hand-written tables. Some data was simply lost as researchers retired or died. In part, the team tracked down analyses by visiting an archive in the Space Flight Center’s basement, where NASA documented every grain of material it had handed out—all in overwhelming masses of paper binders and file folders packed floor to ceiling, with some of the contents already deteriorating.
In the 50-plus years since NASA began collecting material from space, technologies to analyze ever more minute samples in ever more sophisticated ways has greatly advanced, said Lehnert. This means that old data from the archive can be synthesized with newly advanced analyses. Importantly, she added, the agency has been systematically holding back pristine material for future scientists to examine using new techniques. This will include 70 percent of the matter from asteroid Bennu. “Fifty years from now, they will have instrumental improvements that haven’t even been thought of yet,” she said. “It will allow us to make fantastic new discoveries.” | Chemistry and Material Sciences |
Astronomers have turned to deep learning to simulate cosmic explosions that occur when massive stars die, in order to improve their understanding of galactic formation and evolution.
More accurate modeling of tricky-to-simulate aspects of supernovas could shed light on how the chemical elements needed for life are dispersed through the cosmos, researchers say.
The new development is the work of a team led by University of Tokyo astronomer Keiya Hirashima, who was inspired by first applying deep learning — which helps computers recognize patterns across various datasets — to weather for an event called Hackathon.
"Weather is a very complex phenomenon, but ultimately, it boils down to fluid dynamics calculations," Hirashima said in a statement. "So, I wondered if we could modify deep learning models used for weather forecasting and apply them to another fluid system, but one that exists on a vastly larger scale and which we lack direct access to — my field of research, supernova explosions."
How supernovas tie generations of stars together
During their lives, stars forge chemical elements within their cores via nuclear fusion, which smashes together atoms of lighter elements to create heavier elements, with the mass difference released as energy that allows the star to shine. The more massive a star, the heavier the elements it can forge — but all stellar bodies have their limits.
When a star can no longer forge subsequently heavier elements, nuclear fusion stops, and as a result, so does the outward pressure that for millions or billions of years has protected the star against the inward crushing force of its own gravity. As the star's core collapses, the outer layers are flung outward in a massive explosion called a supernova. This spreads the cornucopia of elements the star has crafted during its life into deep space.
This material eventually finds its way into the next generation of stars and the planets orbiting them. Eventually, this star stuff is incorporated into any lifeforms that happen to evolve on those worlds — for instance, humans. That means supernovas are vital to deciphering the origin story of us.
Supernovas are so powerful that they also have a massive influence on the galaxies around them, meaning they are key players in facets of galactic evolution other than chemical enrichment. Thus, knowing how supernovas behave is key to knowing how galaxies change over time.
"The problem is the time it takes to calculate the way supernovae explode. Currently, many models of galaxies over long time spans simplify things by pretending supernovae explode in a perfectly spherical fashion, as this is relatively easy to calculate," Hirashima said. "However, in reality, they are quite asymmetric. Some regions of the shell of material that forms the boundary of the explosion are more complex than others."
The application of deep learning helped the scientists determine which parts of the explosion require more attention during a simulation and which require less. This ensured the best accuracy and also reduced the overall time needed for the calculations involved.
"This way of dividing a problem is called Hamiltonian splitting," Hirashima added. "Our new model, 3D-MIM, can reduce the number of computational steps in the calculation of 100,000 years of supernova evolution by 99%. So, I think we'll really help reduce a bottleneck, too."
That may sound straightforward, but deep learning requires deep training, and to train the system, the team had to run hundreds of simulations, which took millions of hours of computer time. The titanic effort was worth it, with the team now hoping the method used to create 3D-MIM can be applied to other astrophysical phenomena that influence galactic evolution. This includes the birth of large star-forming patches of galaxies called starburst regions.
The team has applied 3D-MIM to the end of stars' lives and could also now apply the same model to the beginning of their lives, thus better modeling stellar birth, too. | Chemistry and Material Sciences |
Earlier this month operators at Webb identified a planet that may contain both a protective atmosphere and a surface covered entirely in oceans—also known as a Hycean world.
One of the main functions of the James Webb Space Telescope is to advance the search for life in the universe by being able to study exoplanets as no other observatory can, and using Webb’s spectrographs, scientists were able to determine that this Hycean world is the perfect place to search.
K2-18b lies 120 light years away from Earth in the constellation Leo, where it orbits the habitable zone of a red dwarf star called K2-18. Believed to be 8.6 times larger than Earth, the abundance of methane and carbon dioxide, and shortage of ammonia detected on the planet supports the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere.
Life emerged under such conditions on Earth, and finding them elsewhere is our best bet to determining if we are not alone in the galaxy.
Promisingly, these initial Webb observations also provided a possible detection of a molecule called dimethyl sulfide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments.
The DMS finding needs to be further validated, say the researchers, who add that because of the light and glare of the host star, it’s extremely difficult to get detailed observations of an exoplanet.
The method used involves waiting until the orbit of the planet around the star takes it between the star and the telescope. The corresponding eclipse signifies the planet is there to be seen, and when it is, Webb can use its NIRISS (Near-Infrared Imager and Slitless Spectrograph) and NIRSpec (Near-Infrared Spectrograph) instruments to image the planet and determine within the wavelengths of light and color which molecules are there on the planet.
However with such a short window of opportunity, even Webb’s exceptional power remains limited.
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“This result was only possible because of the extended wavelength range and unprecedented sensitivity of Webb, which enabled robust detection of spectral features with just two transits,” said Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper.
“For comparison, one transit observation with Webb provided comparable precision to eight observations with Hubble conducted over a few years and in a relatively narrow wavelength range.”
The planet is classified as a “sub-Neptune” meaning one which shares its characteristics but that is smaller than our neighbor. Such planets are believed in some circles to be the most common type of rocky exoplanet.
Analyses from other sub-Neptunes however have shown that they often preclude the possibility to host life, at least as we know it. Their mantles of high-pressure ice and thin atmospheres have almost always led to the ocean either being too hot or simply an ocean of water vapor.
Make A SPLASH On Social Media With This News Of An Ocean World… | Chemistry and Material Sciences |
The Indian Space Research Organisation’s (ISRO) Moon lander Vikram and robotic rover Pragyan have now been told to go to sleep. ISRO hopes to awaken them at lunar dawn on 22 September.
But in their two-week sojourn around the Moon’s south pole, they provided insights that have planetary scientists abuzz. Here are some of the first remarkable findings.
A thin soup of ions and electrons swirls near the lunar pole
A probe onboard Vikram made the first measurements of the density and temperature of Moon’s ionosphere. ISRO reports a “relatively sparse” mix of ions and electrons in the 100-kilometre-thick layer of electrically charged plasma that surrounds the Moon’s surface near the south pole.
Initial measurements of the plasma indicate a density of about 5 million to 30 million electrons per cubic metre. And the density seems to vary as the lunar day progresses, an ISRO scientist analysing the Chandrayaan-3 mission's data told Nature. The peak density of a similar layer in Earth’s upper atmosphere is one million electrons per cubic centimetre.
The density of the ionosphere would affect lunar communication and navigation systems if humans were to inhabit the Moon — the higher the electron density, the longer radio signals take to travel through the ionosphere. The sparse plasma means that potential delays would be “minimal”, the scientist says, and would not pose a problem for transmission.
Temperature variations with depth
Understanding lunar soil, including its temperature and conductivity, will be important when considering settlement on the Moon. The soil “is an important in situ resource for construction”, says Anil Bhardwaj, director of ISRO’s Physical Research Laboratory in Ahmedabad.
The lander is fitted with a temperature probe containing 10 sensors and able to reach 10 centimetres below the surface of the Moon. Its preliminary data show that during the day, the temperature 8 cm down is around 60 ºC lower than at the surface.
Planetary scientist Paul Hayne at the University of Colorado Boulder, says that a steep decline in temperature is expected during the lunar daytime, because the heat does not conduct downward from the warm sunlit surface. “This is similar to the effect one experiences when visiting a beach on a hot day — dig down just a few centimetres and the sand is much cooler,” he says.
Measurements so far have found that the temperature at the surface is significantly warmer than recorded by NASA’s 2009 Lunar Reconnaissance Orbiter, adds Hayne.
The temperatures “are far too warm for water ice to be stable”, says Hayne, explaining that water converts from solid to gas at a very low temperature in the vacuum of space — at about −160 ºC. Chandrayaan-3’s data indicate temperatures warmer than −10 ºC at all depths sampled. Further down "we expect temperatures to flatten out at close to the average surface temperature of about −80 ºC”, says Hayne.
A suspected moonquake
Among many vibrations recorded by the lander’s seismograph, one in particular caught the attention of scientists. The instrument “seems to have recorded a very small seismic event that decayed to background in about 4 seconds”, says planetary geochemist Marc Norman at the Australian National University in Canberra. ISRO scientists suspect it was a small moonquake or the impact of a tiny meteorite.
Such perturbations are expected on the Moon. “Small impacts and local tectonic adjustments related to tidal forces are common on the Moon, but we really need a global seismic network on the Moon and longer-term observations to understand the significance of any particular event,” says Norman.
Sulfur confirmed
Testing by the rover unambiguously confirms the presence of sulfur in the lunar surface near the south pole, ISRO reports. It also found aluminium, silicon, calcium and iron, among other elements.
“Sulfur, being volatile, is not generally expected,” explains Bhardwaj. Confirmation of its presence is really important, say scientists. Sulfur is a key element of molten rock, and researchers think that the primitive Moon was covered with a thick layer of hot molten rock, which crystallized to form the Moon’s surface. Measurements of sulfur concentrations can provide insight into that process, says the ISRO scientist. However, it’s also possible that the sulfur came from asteroids that bombard the Moon’s surface. The ISRO scientist says they hope to add their findings to those of the US Apollo missions to better understand the Moon’s geochemistry. | Chemistry and Material Sciences |
A small capsule carrying pristine specimens from an asteroid parachuted to landing in the Utah desert Sunday, capping a seven-year voyage through the Solar System to bring home samples for eager scientists seeking clues about the origins of life.
NASA's OSIRIS-REx mission brought back the largest unspoiled sample of material ever returned to Earth from beyond the Moon, probably on the order of about 250 grams, or roughly 8 ounces, according to estimates. The spacecraft collected the samples from asteroid Bennu, a loosely-bound rocky world about the size of a small mountain, during a touch-and-go landing in October 2020.
It's the third asteroid sampling mission in history, and the first for the United States, following two Japanese spacecraft that returned a smaller quantity of asteroid specimens to Earth in 2010 and 2020.
OSIRIS-REx was tinged with suspense and drama from start to finish. The project's original lead scientist died in 2011, months after NASA selected his mission concept for funding. In 2016, the spacecraft was stacked on top of its United Launch Alliance Atlas V rocket awaiting liftoff from Cape Canaveral, Florida, when a SpaceX Falcon 9 rocket exploded during a ground test barely a mile away. That sent thick plumes of black smoke over the Atlas V launch pad and briefly knocked offline an air conditioning system needed to keep OSIRIS-REx safe before launch.
Then, in 2020 when OSIRIS-REx collected its sample from Bennu, the spacecraft overfilled its collection chamber. The asteroid was made of much looser material than scientists predicted, so diffuse that the spacecraft could have kept plowing into Bennu had it not performed a pre-planned back-away maneuver.
At the end of its 4-billion-mile celestial journey, the OSIRIS-REx mothership spacecraft released a 32-inch-wide (81-centimeter) sample return capsule early Sunday as it darted toward Earth. More than four hours later, the capsule landed at the US Air Force's Utah Test and Training Range southwest of Salt Lake City at 8:52 am local time (10:52 am EDT or 14:52 UTC).
Scientists working on NASA's $1 billion OSIRIS-REx mission watched anxiously as the capsule came back to Earth, braving temperatures of more than 5,000 degrees Fahrenheit after slamming into the atmosphere at 27,650 mph (12.3 kilometers per second).
Radar sensors and infrared tracking cameras glimpsed the capsule as aerodynamic forces rapidly decelerated the vehicle, subjecting it to 32 times the force of Earth's gravity before an orange and white main parachute opened at an altitude of about 20,000 feet (6,100 meters).
This was about four times higher than predicted, with the chute deployment triggered by a sensor on-board the capsule measuring its deceleration. It wasn't immediately clear whether a drogue parachute meant to stabilize the capsule actually opened before the main chute, as was designed.
In any event, the main parachute did its job and delivered the capsule to the desert surface for a relatively gentle landing at about 10 to 11 mph (17 kilometers per hour). Within minutes, a safety official from the military test range approached the blackened capsule with a safety engineer from Lockheed Martin, which built the OSIRIS-REx spacecraft for NASA.
The ground team then wrapped the capsule inside Teflon bags and put it into a safety net under a helicopter, which carried it to a nearby clean room facility at the US Army's Dugway Proving Ground. Technicians there quickly unwrapped the capsule and started disassembling it for transport by cargo plane Monday to NASA's Johnson Space Center in Houston, where scientists inside a specially-built super-clean curation facility will open the lid of the capsule's inner chamber Tuesday.
OSIRIS-REx is an acronym that stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer. That's a lot to unpack, but it's sufficient to say the mission is all about bringing asteroid material back to Earth for detailed analyses in research laboratories, which boast capabilities far beyond even the most sophisticated science instrument on a spacecraft.
NASA plans to announce some preliminary findings from the asteroid sample October 11, but more detailed results will take longer. Scientists hope to release the first peer-reviewed research papers analyzing the asteroid specimens by the end of the year, with more results trickling out in 2024. Some of the material will be sent to labs in Canada and Japan, in recognition for those countries' partnership on OSIRIS-REx. A large portion of the specimens will be set aside for future researchers, who may have the benefit of more advanced lab technology.
"Grandfather rocks"
Scientists are eager to find out what OSIRIS-REx captured back in 2020, but observations from the spacecraft's on-board instruments give them some important indicators.
Measurements from OSIRIS-REx, and from telescopes before the mission ever launched, showed Bennu is rich in carbon-based minerals. These are the building blocks of life, and scientists theorize asteroids like Bennu delivered the seeds of life to Earth billions of years ago.
In the chaotic early history of the Solar System, soon after the Sun flashed to life 4.5 billion years ago, a disk of gas and dust around the newborn star started aggregating together—first into grains of dust, then into snowflake-like particles that gradually came together to form asteroids and planets. Scientists think Bennu is a leftover relic from that era.
"The biggest question, the one that drives my scientific investigations, is the origin of life. What is life? How did it originate? And why was it on Earth that it occurred?" said Dante Lauretta, principal investigator on the OSIRIS-REx mission from the University of Arizona. "We believe that we’re bringing back... maybe representatives of the seeds of life that these asteroids delivered at the beginning of our planet, that led to this amazing biosphere, biological evolution, and to us being here today to look back at that amazing history.
“We’re literally looking at geologic materials that formed before the Earth even existed," Lauretta said. "I call these the grandfather rocks, the ones that really represent our origins and where we came from.”
OSIRIS-REx launched from Cape Canaveral aboard an Atlas V rocket on September 8, 2016. It arrived at Bennu at the end of 2018, setting up for the touch-and-go landing two years later. As the spacecraft descended to Bennu, it stuck a robotic arm and a sampling head out in front to grab clumps of rock from the asteroid's surface. The spacecraft sent out a burst of gas to funnel bits of Bennu into a sample collection chamber.
It didn't take long for scientists to realize that Bennu threw them a curveball. The asteroid material at the sampling site was less dense than researchers predicted—about one-sixth the density of a typical rock on Earth—and the touch-and-go landing launched a spray of particles around the spacecraft.
Lauretta compared the dynamics of the sampling run as akin to dropping yourself into a ball pit at a children's playground. "It literally is a droplet made out of rock, gravel, and boulders that are barely held together by their own microgravity.”
So much material went into the sampling system that its lid was wedged open, and smaller pieces of rock started floating out.
That prompted ground teams to accelerate their plan to seal the sampling system inside the return capsule, ensuring no more specimens were lost to space. The capsule is designed like a nesting doll, with a carbon-based ablative heat shield on the outside to protect it from the blistering temperatures of re-entry back into Earth's atmosphere. Inside the heat shield is the sample canister itself, which envelops the sampling head detached from the end of the OSIRIS-REx robot arm.
If it really brought back 250 grams of asteroid material, that is about four times the mission's required sample mass. Scientists won't know the precise mass of the asteroid sample until they transport the canister to a dedicated laboratory in Houston and open it up.
Scientists were thrilled with the successful recovery of OSIRIS-REx samples Sunday, but one more potential snag is on the horizon. The federal government could enter a shutdown if Congress does not pass a new budget and President Biden doesn't sign it by midnight on October 1. With the intense political wrangling in Washington, this appears increasingly likely.
In the event of a government shutdown next month, some of the steps needed to prepare the asteroid sample for analysis will "possibly be delayed," said Lori Glaze, head of NASA's planetary science division.
“We will make sure, first and foremost, that this sample is safe and not at risk," she said. "We have time for that after it returns to Johnson Space Center on September 25. The sample has waited for more than 4 billion years for humans to study it, and if it takes us a little longer, I think we'll be OK.”
Seeds of life
Bennu is classified as a near-Earth asteroid because its orbit around the Sun regularly brings it close to our planet. That made Bennu an attractive target because it's part of the population of asteroids that could threaten Earth, and one that was relatively easy for OSIRIS-REx to reach, in terms of the amount of energy needed to get there and get back home.
Researchers have, for many years, studied carbonaceous meteorites that fell to Earth after breaking off larger asteroids. Those meteorites were scorched as they fell into the atmosphere, and then exposed to Earth's environment for long periods of time until their recovery. The samples from Bennu are unspoiled.
“We’ve been studying meteorites that we think look like Bennu, so I fully expect to find amino acids, the building blocks of proteins, sugars, an energy source for life, nucleobases, parts of the genetic code," said Danny Glavin, a senior scientist for sample return at NASA. "So we’ll see what Bennu tells us. One thing I’ve learned from this mission is (there have been) so many surprises. Sample analysis, probably, won’t be an exception. We're going to be surprised.
“One of the challenges with all meteorites is they get contaminated," Glavin said. "You’re looking for the building blocks of life, and the contamination really makes it hard to tease out what formed in space. That’s why this is so special, these Bennu samples (with) pristine materials. We’re going to be able to trust the organic results from these samples.”
Regardless of the precise composition of the Bennu sample, the material is almost certainly primitive and similar to charcoal in color, appearing much as it did soon after the formation of the Solar System.
“One of the key objectives of OSIRIS-REx is to characterize any organic molecules that may have been delivered to the early Earth by these carbon-rich bodies," Lauretta said. "We expect that we'll find what we call monomers, or very simple molecules, for example, amino acids, which many people may be familiar with, because they make up our proteins. If you take protein supplements, you can often see the list of amino acids that are included in that."
"What would be really exciting is if we saw any evidence that those amino acids had started to link together to form a chain, which we call peptides," he said. "That would give us some indication that towards the origin of life, protein evolution may have occurred. I want to say that’s a hope. It’s probably a long shot, but it would be a spectacular science result if we were to discover something like that.”
Next stop: Apophis
After releasing its sample return capsule, the OSIRIS-REx mothership fired thrusters to steer away from its collision course with Earth. The spacecraft soared a few hundred miles above the planet, heading back into the Solar System to continue with an extended mission to explore a different asteroid.
This next target, named Apophis, is an elongated asteroid with an average diameter of about 1,100 feet (340 meters). It became one of the Solar System's most famous—infamous?—asteroids soon after its discovery in 2004. At that time, preliminary tracking of the asteroid indicated there was a small chance it could impact Earth on April 13, 2029. Since then, more refined data on the orbit of Apophis have eliminated any chance it will strike Earth for at least the next 100 years.
Apophis is a stony asteroid, different in composition from Bennu. This is the most common type of asteroid that could threaten Earth, so scientists want to learn about Apophis' bulk structure and surface strength. Data collected at Apophis could inform predictions of how much damage a future asteroid impact threat could cause if it impacted Earth.
This new extended mission, called OSIRIS-Apophis Explorer (OSIRIS-APEX), will take the spacecraft on several more loops around the Sun. Soon after Apophis passes less than 20,000 miles (32,000 kilometers) from Earth in 2029, the OSIRIS-APEX spacecraft will enter orbit around the asteroid for more than a year of close-up observations.
The spacecraft's time at asteroid Apophis will include another touch-and-go landing, where it will use its thrusters to stir up material and dig into the surface. "This will allow us to observe subsurface material, which will provide otherwise inaccessible insight into space weathering and the surface strength of stony asteroids," researchers at the University of Arizona wrote on the mission's website.
Repurposing the OSIRIS-REx spacecraft for this extended mission is much less expensive than building a new mission to visit Apophis. | Chemistry and Material Sciences |
A NASA capsule carrying the largest sample ever collected from an asteroid has returned to Earth.
The capsule, which landed in the Utah desert, contained around 250g of rocks and dust collected from asteroid Bennu as part of NASA's Osiris-Rex mission.
Experts say the carbon-rich, near-Earth asteroid serves as a time capsule from the earliest history of the solar system.
Read more: NASA probe returns with rock samples - watch and follow live
It is anticipated the sample will provide important clues that could help us to understand the origin of organics and water that may have led to life on Earth.
Because the sample has been collected directly from the asteroid, there will be almost zero contamination.
It glowed red hot as it hit the upper atmosphere and plunged towards the Earth, with temperatures inside expected to peak at 2,800C.
Parachutes then deployed near the very end of its descent to safely bring the sample to the ground in the Utah desert.
It is the US space agency's first mission to collect a sample from an asteroid and the first by any agency since 2020.
A quarter of the sample will be given to a group of more than 200 people, from 38 globally distributed institutions, including a team of scientists from the University of Manchester and the Natural History Museum.
Asteroid Bennu is a 4.5-billion-year-old remnant of the early solar system and is classified as a "near-Earth object" because it passes relatively close to our planet every six years, though the odds of an impact are considered remote.
In 2021, scientists with the Osiris-Rex team said the asteroid could possibly drift into Earth's orbit and hit the planet by September 2182, though there was a one in 2,700 (0.037%) chance that could happen.
NASA launched the robotic spacecraft Osiris-Rex on 8 September 2016 and it arrived at asteroid Bennu in December 2018. The celestial object is 500m (1,600ft) across - slightly wider than the Empire State Building is tall. After mapping Bennu for nearly two years Osiris-Rex collected a sample from the surface on 20 October 2020 before beginning its return to Earth on 10 May 2021. Scientists believe studying the carbon-rich asteroid can help shed light on how planets formed and evolved. They say Bennu serves as a time capsule from the earliest history of the solar system. The sample is anticipated to provide important clues that could help our understanding of the origin of organics and water that may have led to life on Earth. After depositing its sample on Earth the Osiris-Rex spacecraft is expected to sail on to explore another near-Earth asteroid named Apophis.
Study 'crucial for understanding formation of planets like Earth'
Ashley King, UKRI future leaders fellow, Natural History Museum, said: "Osiris-Rex spent over two years studying asteroid Bennu, finding evidence for organics and minerals chemically altered by water.
"These are crucial ingredients for understanding the formation of planets like Earth, so we're delighted to be among the first researchers to study samples returned from Bennu.
"We think the Bennu samples might be similar in composition to the recent Winchcombe meteorite fall, but largely uncontaminated by the terrestrial environment and even more pristine."
Dr Sarah Crowther, research fellow in the Department of Earth and Environmental Sciences at the University of Manchester, said: "It is a real honour to be selected to be part of the Osiris-Rex sample analysis team, working with some of the best scientists around the world.
"We're excited to receive samples in the coming weeks and months, and to begin analysing them and see what secrets asteroid Bennu holds.
"A lot of our research focuses on meteorites and we can learn a lot about the history of the solar system from them.
"Meteorites get hot coming through Earth's atmosphere and can sit on Earth for many years before they are found, so the local environment and weather can alter or even erase important information about their composition and history.
"Sample return missions like Osiris-Rex are vitally important because the returned samples are pristine, we know exactly which asteroid they come from and can be certain that they are never exposed to the atmosphere so that important information is retained." | Chemistry and Material Sciences |
Hexagon-tiled rock newly uncovered on Mars suggests that the Red Planet underwent a repeated cycle of wet and dry spells for up to millions of years that could have supported the emergence of life, a new study finds.
Although Mars is now cold and dry, researchers have for decades found evidence suggesting that the planet's surface was once covered with rivers, streams, ponds, lakes and perhaps even seas and oceans. Since there is life virtually everywhere on Earth where there is water, these ancient signs of water on the Red Planet raise the possibility that Mars was once home to life — and might host it still.
However, previous research suggested that dry spells may have also proven helpful to the evolution of life. Organic compounds that may have formed in water during wet times could have concentrated together in dry times, supporting chemical reactions that could have led to the emergence of life on Mars.
"On Earth, people have run experiments that have shown that if you subject a rock to cycles of wet and dry spells, simple organic molecules can combine and form larger molecules, such as proteins, and even RNA and DNA," study lead author William Rapin, a research scientist at the French National Center for Scientific Research in Toulouse, France, told Space.com.
Now, using NASA's Curiosity rover, scientists have discovered signs that sites on early Mars underwent repeated cycling between wet and dry times. "We now have for the first time vestiges of times that could have been conducive to the origin of life," Rapin said.
In the new study, researchers focused on 3.6-billion-year-old rocks in Gale Crater, where Curiosity landed in August 2012. "We've seen mud cracks before, but the one at this location typically had T-shaped junctions," Rapin said. "This happens when the mud dried once and was fossilized in that state."
In contrast, the scientists found mud cracks shaped like hexagons, which originated from Y-shaped junctions. "That was really exciting to us — it was an unexpected type of rock, something we hadn't seen on Mars before," Rapin said.
The researchers suggested these are fossilized cracks from ancient mud in a lakebed that regularly went through cycles of wet and dry times, possibly in a seasonal manner. "This formation had some depth, which tells us this cycling was sustained for a prolonged period, up to millions of years," Rapin said.
Previous research may not have detected such cracks because these are delicate features prone to erosion. "Here, they are exceptionally preserved," Rapin said.
Curiosity found sulfate salts at this formation. "Now we can look elsewhere on Mars at sites with these chemical traces from the same time to find signs of these climates and environments," Rapin said.
All in all, "so far, research has focused on the question of whether life arose on Mars, and now we can also look for traces of how might life have arisen on Mars," Rapin said.
The scientists detailed their findings online Wednesday (Aug. 9) in the journal Nature. | Chemistry and Material Sciences |
Nasa's James Webb Space Telescope may have discovered tentative evidence of a sign of life on a faraway planet.
It may have detected a molecule called dimethyl sulphide (DMS). On Earth, at least, this is only produced by life.
The researchers stress that the detection on the planet 120 light years away is "not robust" and more data is needed to confirm its presence.
Researchers have also detected methane and CO2 in the planet's atmosphere.
Detection of these gases could mean the planet, named K2-18b, has a water ocean.
Prof Nikku Madhusudhan, of the University of Cambridge, who led the research, told BBC News that his entire team were ''shocked'' when they saw the results.
"On Earth, DMS is only produced by life. The bulk of it in Earth's atmosphere is emitted from phytoplankton in marine environments," he said.
Caution
But Prof Madhusudhan described the detection of DMS as tentative and said that more data would be needed to confirm its presence. Those results are expected in a year.
''If confirmed, it would be a huge deal and I feel a responsibility to get this right if we are making such a big claim.''
It is the first time astronomers have detected the possibility of DMS in a planet orbiting a distant star. But they are treating the results with caution, noting that a claim made in 2020 about the presence of another molecule, called phosphine, that could be produced by living organisms in the clouds of Venus was disputed a year later.
Even so, Dr Robert Massey, who is independent of the research and deputy director of the Royal Astronomical Society in London, said he was excited by the results.
''We are slowly moving towards the point where we will be able to answer that big question as to whether we are alone in the Universe or not," he said.
''I'm optimistic that we will one day find signs of life. Perhaps it will be this, perhaps in 10 or even 50 years we will have evidence that is so compelling that it is the best explanation.''
JWST is able to analyse the light that passes through the faraway planet's atmosphere. That light contains the chemical signature of molecules in its atmosphere. The details can be deciphered by splitting the light into its constituent frequencies - rather like a prism creating a rainbow spectrum. If parts of the resulting spectrum are missing, it has been absorbed by chemicals in the planet's atmosphere, enabling researchers to discover its composition.
The feat is all the more remarkable because the planet is more than 1.1 million billion km away, so the amount of light reaching the space telescope is tiny.
As well as DMS, the spectral analysis detected an abundance of the gases methane and carbon dioxide with a good degree of confidence.
The proportions of CO2 and methane are consistent with there being a water ocean underneath a hydrogen-rich atmosphere. Nasa's Hubble telescope had detected the presence of water vapour previously, which is why the planet, which has been named K2-18b, was one of the first to be investigated by the vastly more powerful JWST, but the possibility of an ocean is a big step forward.
Recipe for life
The ability of a planet to support life depends on its temperature, the presence of carbon and probably liquid water. Observations from JWST seem to suggest that that K2-18b ticks all those boxes. But just because a planet has the potential to support life it doesn't mean that it does, which is why the possible presence of DMS is so tantalising.
What makes the planet even more intriguing is that it is not like the Earth-like, so called rocky planets, discovered orbiting distant stars that are candidates for life. K2-18b is nearly nine times the size of Earth.
Exoplanets - which are planets orbiting other stars - which have sizes between those of Earth and Neptune, are unlike anything in our solar system. This means that these 'sub-Neptunes' are poorly understood, as is the nature their atmospheres, according to Dr Subhajit Sarkar of Cardiff University, who is another member of the analysis team.
"Although this kind of planet does not exist in our solar system, sub-Neptunes are the most common type of planet known so far in the galaxy," he said.
"We have obtained the most detailed spectrum of a habitable-zone sub-Neptune to date, and this allowed us to work out the molecules that exist in its atmosphere."
Follow Pallab on X, formerly known as Twitter | Chemistry and Material Sciences |
Scientists have recently unveiled compelling new data about the Psyche asteroid, a celestial object laden with precious metals and valued at an astounding $10,000 quadrillion. NASA’s Psyche Mission launches in October 2023 with the goal of sorting fact from fiction.
This vast wealth theorized by astronomers and mission scientists arises from Psyche’s distinct composition. Most other asteroids contain rocky or icy materials, but metals largely compose Psyche.
Psyche, a 124-mile-wide space rock, dwells within the asteroid belt, a ring of over a million rocks orbiting the sun between Mars and Jupiter.
Some researchers suggest that Psyche might have been the core of a planet in its early development. NASA aims to explore this theory through a mission set to launch this year in October 2023.
To aid NASA’s mission, researchers at the California Institute of Technology (Caltech) have created a temperature map of Psyche’s surface. Traditional infrared imaging of asteroids yields a single pixel of data.
However, using the Atacama Large Millimeter/submillimeter Array (ALMA) located in Chile, the team was able to generate a 50-pixel resolution image of Psyche. This offered a more detailed view of its surface.
The higher resolution enabled the team to conclude that Psyche’s surface is at least 30% metal.
The presence of metallic grains scattered throughout the surface rocks suggests this composition.NASA may use this finding to guide their planned observations.
Psyche, also known as Psyche 16, was first discovered in 1852. Researchers believe that Psyche is the remnants of a protoplanet, destroyed by violent collisions during the formation of the solar system. It stands out among celestial bodies due to its suspected composition of mostly iron and nickel, which gives it enormous potential mining value.
Before NASA’s scheduled mission, the Caltech team closely analyzed the millimeter-wavelength emissions from Psyche. This study allowed them to generate the first-ever temperature map of Psyche, offering unprecedented insights into the asteroid’s surface properties.
“The findings are a step toward resolving the mystery of the origin of this unusual object, which has been thought by some to be a chunk of the core of an ill-fated protoplanet,” the study authors explain.
Psyche is the largest known M-Type asteroid. Researchers believe this category of asteroids to be rich in metal and potentially containing fragments of protoplanet cores. The precious metals theory aligns with our understanding of the early solar system as a violent environment where planetary bodies constantly collided and settled into their current orbits.
“Low thermal inertia is typically associated with layers of dust, while high thermal inertia may indicate rocks on the surface,” says Saverio Cambioni, a Caltech researcher. “However, discerning one type of landscape from the other is difficult.”
Researchers Katherine de Kleer, Saverio Cambioni, and Michael Shepard from Bloomsburg University in Pennsylvania utilized ALMA’s 66 radio telescopes to map Psyche’s thermal emissions. With each pixel representing an 18-mile by 18-mile area, the map provides much higher resolution data than typically achievable for these asteroid belt rocks.
The scientists’ analysis of this data revealed that Psyche’s thermal inertia is higher than that of a typical asteroid. This suggests it has a remarkably dense or conductive surface.
Additionally, the researchers found that Psyche’s thermal emission – the amount of heat it radiates – is 60% of what would be expected from a surface with standard thermal inertia. This finding indicates that metal makes up at least 30% of Psyche’s surface.
Further analysis suggested that metallic grains pepper the surface rocks of Psyche, based on the light it emitted. As de Kleer points out, “We’ve known for many years that objects in this class are not, in fact, solid metal, but what they are and how they formed is still an enigma.”
These findings have given rise to alternative theories about Psyche’s surface composition. One theory posits that it might be a very old asteroid formed closer to the sun, rather than the core of a fragmented protoplanet.
Building upon their success with Psyche, the team plans to apply these techniques to other large objects in the asteroid belt. This research was facilitated by a related project led by Michael Shepard at Bloomsburg University. Shepard’s project combined data from several telescopes to determine Psyche’s size, shape, and orientation.
Italian astronomer Annibale de Gasparis named the asteroid Psyche after the Greek goddess of the soul. It’s the primary target of NASA’s Psyche mission, which will launch in October and arrive at the asteroid in 2026.
Over 21 months, the spacecraft will use a variety of instruments to study Psyche’s properties and determine whether it is indeed a planetary core or simply a large metal asteroid. The full findings of this research have been published in the Planetary Science Journal.
The Psyche Mission is an unprecedented NASA expedition. This bold mission is setting its sights on asteroid 16 Psyche, a massive celestial body made up almost entirely of metal.
The mission holds a unique place in the annals of space exploration, as it aims to study a planetary body unlike any other that we have investigated thus far. 16 Psyche resides in the main asteroid belt between Mars and Jupiter. It offers potential insights into the violent collisions that created Earth and other terrestrial planets.
The Psyche Mission, targeting the unique metal asteroid 16 Psyche, has four primary scientific objectives:
The mission aims to understand if 16 Psyche is indeed the exposed core of an early planet. This knowledge would help clarify the processes that went into the formation of terrestrial planets in our solar system.
By determining the age of 16 Psyche, scientists can glean insights into the age of the early solar system. This could potentially refine our understanding of solar system evolution.
The mission seeks to map and characterize the morphology of 16 Psyche. This study will give us detailed knowledge about Psyche’s surface features and structure.
By studying the elemental composition of 16 Psyche, the mission can identify the asteroid’s building blocks. This data could provide valuable insights into the constituents of early planetary bodies.
Together, these objectives strive to deepen our understanding of the formative processes of planetary bodies and the history of our solar system.
The Psyche spacecraft and its associated instruments represent a blend of innovative technology and tried-and-true systems proven in the harsh environment of space. Here are the key components of the spacecraft and the onboard scientific instruments:
The spacecraft itself features a high-gain antenna for communication with Earth, enabling the transfer of data collected during the mission. It also includes two solar arrays for power generation, essential for operating in the far reaches of the solar system.
Scientists designed this instrument to capture high-resolution images of 16 Psyche’s surface. It uses a variety of filters to discern the asteroid’s geology and composition.
These images will be critical in achieving the mission’s goals of understanding Psyche’s topography and elemental makeup.
The GRNS will measure the composition of 16 Psyche. It provides data about the distribution of various elements on the asteroid’s surface, which will offer clues to the asteroid’s origins and formation.
This instrument will measure the remnant magnetic field of 16 Psyche. By studying Psyche’s magnetic field, scientists can learn more about the asteroid’s history, its core formation, and potentially, the processes involved in the creation of planet cores.
This system isn’t a scientific instrument in the traditional sense, but it serves a scientific purpose. It will be used to measure Psyche’s gravity field and, in turn, provide insight into its internal structure.
Each of these instruments has a crucial role to play in the Psyche Mission, allowing scientists to gather the data needed to meet the mission’s objectives.
The Psyche Mission’s timeline is meticulously planned to navigate the complexities of space travel and rendezvous with the asteroid 16 Psyche. Here is a detailed look at the timeline:
NASA announced the Psyche Mission as part of its Discovery Program, which funds relatively low-cost, focused scientific investigations of the solar system.
The Psyche spacecraft, now fully assembled, includes solar panels, which fold during transport and launch. When the solar panels are unfolded, the spacecraft spans about 81 feet long (24.76 meters).
This is about the size of a singles tennis court. The body of the spacecraft is about 10 feet long (3.1 meters) and almost 8 feet (2.4 meters) wide.
At the launch site the team conducts an entire re-check of the spacecraft before integrating into the launch vehicle. The launch period for the Psyche spacecraft is October 5-25, 2023. Once in space, the spacecraft travels using solar-electric propulsion.
The Psyche spacecraft is scheduled to perform a gravity assist maneuver using Mars in 2024. This gravity assist will increase the spacecraft’s speed, saving on fuel and shortening the travel time to 16 Psyche.
The spacecraft is projected to reach the asteroid 16 Psyche in 2026. Upon arrival, it will commence a 21-month observation period.
During this period, the spacecraft will orbit 16 Psyche at varying distances, mapping and studying the asteroid’s properties. The collected data will contribute to our understanding of this unique metal world and the formative history of the solar system.
This timeline provides a roadmap of the Psyche Mission. It marks significant milestones, from the project’s announcement to the spacecraft’s anticipated arrival at 16 Psyche. Each step contributes to the overall mission’s goal of understanding the nature and history of 16 Psyche. Also, by extension, the early solar system.
The Psyche Mission holds significant implications for our understanding of the solar system and the potential for future space exploration and resource utilization. Its importance can be highlighted in the following ways:
The mission’s primary goal is to determine whether 16 Psyche is the exposed metallic core of an early planet. If this is true, studying 16 Psyche will provide us with unprecedented insights into the violent history of collisions and accretion that led to the formation of terrestrial planets.
By investigating the age and composition of 16 Psyche, the mission aims to glean crucial insights into the early solar system. This data could help refine our understanding of the processes that have led to the solar system’s current state.
The exploration of 16 Psyche can help us understand the cores of other planets, including Earth, which we can’t observe directly. The insights gleaned can potentially revolutionize our knowledge of planetary interiors.
16 Psyche, given its composition, may harbor valuable metals. The knowledge gained from the Psyche mission could open new avenues for asteroid mining. This would provide resources for both on Earth and in-space manufacturing.
In summary, the Psyche Mission’s significance extends from enhancing our understanding of our solar system’s past to potentially paving the way for future space resource utilization. It’s a bold step in our continuing quest to understand our place in the cosmos.
In a journey poised to revolutionize our understanding of planetary formation, the Psyche Mission epitomizes our bold quest for knowledge and exploration. This pioneering endeavor could hold the keys to untold secrets of our solar system.
As we await the first intimate observations of 16 Psyche, we look forward to a future where the depths of space become less of a mystery and more of a testament to our scientific and exploratory prowess.
— | Chemistry and Material Sciences |
Mysterious ultra-high energy source investigated by astronomers
Astronomers from the University of Maryland and the Michigan Technological University, have inspected a mysterious ultra-high energy gamma-ray source known as LHAASO J2108+5157. Results of the study, published August 31 on the pre-print server arXiv, could help us unveil the true nature of this source.
Sources emitting gamma radiation with photon energies between 100 GeV and 100 TeV are called very-high energy (VHE) gamma-ray sources, while those with photon energies above 0.1 PeV are known as ultra-high energy (UHE) gamma-ray sources. The nature of these sources is still not well understood; therefore, astronomers are constantly searching for new objects of this type to characterize them, which could shed more light on their properties in general.
A team of astronomers led by University of Maryland's Sajan Kumar decided to take a closer look at one such UHE gamma-ray source designated LHAASO J2108+5157. It is a point-like source with an extension less than 0.39 degrees, known to be associated with the molecular cloud [MML2017]4607—located some 10,700 light years away.
Previous observation of LHAASO J2108+5157 detected no X-ray counterparts and it turned out that the closest X-ray source is the eclipsing binary RX J2107.3+5202 with the separation of about 0.3 degrees. Given that no powerful pulsars or supernova remnants have been detected so far in the vicinity of LHAASO J2108+5157, it is difficult to determine the origin of its gamma-ray emission as it can be explained either by hadronic and leptonic models.
Therefore, Kumar's team observed LHAASO J2108+5157 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) and the High-Altitude Water Cherenkov Observatory (HAWC) in order to shed more light on the emitted UHE gamma-rays.
The observations found no significant emission close to the position of LHAASO J2108+5158. The astronomers also performed spectral analysis on the circular region with the radius of 0.09 degrees around the position of LHAASO J2108+5157, measuring differential flux upper limits at 1.0, 3.98, and 15.38 TeV energy—consistent with previous studies.
The obtained upper limits exclude the hadronic model and suggest a leptonic origin of emission from few TeV to hundreds of TeV energy. However, the researchers noted that a new molecular cloud has been recently identified in the vicinity of LHAASO J2108+5157, what sheds more light on the origin of the observed gamma-ray emission.
"The morphology of this new cloud highly correlates with the LHAASO J2108+5157 gamma-ray emission up to 2 GeV from Fermi-LAT and emission detected by LHAASO. This makes it more likely that the gamma rays are produced through the hadronic channel with molecular cloud as the main target for the cosmic ray particles accelerated by unidentified PeVatrons," the astronomers concluded.
They added that future observations by CTA and analysis in the X-ray band are required in order to fully understand the nature of LHAASO J2108+5157.
More information: Sajan Kumar et al, VERITAS and HAWC observations of unidentified source LHAASO J2108+5157, arXiv (2023). DOI: 10.48550/arxiv.2309.00089
Journal information: arXiv
© 2023 Science X Network | Chemistry and Material Sciences |
Neptune, the eighth and final planet from the sun, is known for its trails of wispy white clouds made up of crystals of frozen methane.
Strong winds whip these clouds across the ice giant at speeds of more than 1,200 mph – the fastest recorded anywhere in the solar system.
But a new study shows they have now all but vanished, in a development that briefly baffled scientists.
Experts have since discovered that the clouds disappear and reappear according to where the sun is in its 11-year cycle.
They discovered this after studying images from the Hubble Space Telescope dating back to 1994.
A new study describing the findings – led by astronomers at the University of California, Berkeley – has been published in the journal Icarus.
'I was surprised by how quickly clouds disappeared on Neptune,' said Imke de Pater, emeritus professor of astronomy at UC Berkeley.
'We essentially saw cloud activity drop within a few months.'
Neptune, the fourth largest planet in our solar system, is an ice giant – a huge planet made up of a thick soup of water, methane and ammonia, which scientists refer to as 'ices'.
Above this, in its upper atmosphere, are the planets distinctive swirling clouds, which reflect all the colours of the spectrum in the sun's light, making them white.
It was in 1989 that NASA's Voyager 2 spacecraft provided the first close-up images of these bright clouds – reminiscent of cirrus clouds on Earth – high in Neptune's atmosphere.
Wrapped in teal- and cobalt-colored bands of clouds, the planet looked like a blue-hued sibling to Jupiter and Saturn, the blue indicating the presence of its methane.
To monitor the evolution of Neptune's clouds, researchers analysed images from Hubble.
They also studied data from California's Lick Observatory between 2018 and 2019 and the Keck Observatory in Hawaii from 1994 to 2022.
They found an abundance of clouds normally seen at the icy giant's mid-latitudes started to fade in 2019 – and since then they haven't gone back to how they were.
From late 2019 onwards, only the south pole showed cloud activity.
'Even now, four years later, the most recent images we took this past June still show the clouds haven't returned to their former levels,' said Erandi Chavez at Harvard's Center for Astrophysics in Cambridge, Massachusetts.
'This is extremely exciting and unexpected, especially since Neptune's previous period of low cloud activity was not nearly as dramatic and prolonged.'
Data also revealed a connection between Neptune's disappearing clouds and the solar cycle – the period when the sun's magnetic field flips every 11 years, causing levels of solar radiation to fluctuate.
This was surprising because Neptune is the farthest planet from the sun and doesn't receive much sunlight – around only 1/900th of the sunlight we get on Earth.
The team found that two years after the solar cycle's peak, an increasing number of clouds appear on Neptune.
It's thought the sun's UV rays, when strong enough, may be triggering a photochemical reaction that produces Neptune's clouds.
The team further found a positive correlation between the number of clouds and the ice giant's brightness from the sunlight reflecting off it.
When the the planet's reflectivity reached its lowest level ever observed in 2020, most of the clouds went away.
The study heavily suggests Neptune's global cloudy weather is driven by solar activity and not the planet's four seasons, which each last approximately 40 years.
'Our data provide the strongest evidence to date that the discrete cloud coverage appears correlated with the solar cycle,' the team say in their paper.
Further observations of Neptune are also needed to see how long the current near-absence of clouds will last, they add.
This may help deepen understanding not only of Neptune but also of exoplanets – planets outside of our solar system.
This is because exoplanets are thought to have Neptune-like qualities, such a rocky core surrounded by a thick atmosphere of hydrogen and helium. | Chemistry and Material Sciences |
By analyzing tiny lunar crystals gathered by Apollo 17 astronauts in 1972, researchers recalculated the age of the Earth’s Moon. Although previous assessments estimated the Moon as 4.425 billion years old, the new study discovered it is actually 4.46 billion years old — 40 million years older than previously thought.
Led by researchers at the Field Museum and the University of Glasgow, the study was made possible by Northwestern University’s atom-probe tomography facility, which “nailed down” the age of the oldest crystal in the sample. By revealing the age of these telltale zircon crystals — found hidden within dust collected from the Moon — researchers were able to piece together the timeline of the Moon’s formation.
The study was published Oct. 23 in the journal Geochemical Perspectives Letters.
“This study is a testament to immense technological progress we have made since 1972 when the last manned Moon mission returned to Earth,” said Northwestern’s Dieter Isheim, who co-authored the study. “These samples were brought to Earth half-a-century ago, but only today do we have the necessary tools to perform microanalysis at the requisite level, including atom-probe tomography.”
The atom-by-atom analysis enabled researchers to count how many atoms in the zircon crystals have undergone radioactive decay. When an atom undergoes decay, it sheds protons and neutrons to transform into different elements. Uranium, for example, decays into lead. Because scientists have established how long it takes for this process to unfold, they can assess the age of a sample by looking at the proportion of uranium and lead atoms.
“Radiometric dating works a little bit like an hourglass,” said the Field Museum’s Philipp Heck, the study’s senior author. “In an hourglass, sand flows from one glass bulb to another, with the passage of time indicated by the accumulation of sand in the lower bulb. Radiometric dating works similarly by counting the number of parent atoms and the number of daughter atoms they have transformed to. The passage of time can then be calculated because the transformation rate is known.” | Chemistry and Material Sciences |
NASA/JPL-Caltech
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An artist's conception of the Psyche spacecraft approaching an asteroid that's largely composed of metal.
NASA/JPL-Caltech
An artist's conception of the Psyche spacecraft approaching an asteroid that's largely composed of metal.
NASA/JPL-Caltech
NASA is about to launch a spacecraft on a nearly six-year journey to a strange asteroid that, unlike most space rocks, seems largely to be made of metal.
"This will be our first time visiting a world that has a metal surface," says Lindy Elkins-Tanton of Arizona State University, the principal investigator for this mission, who notes that previous NASA efforts have looked at worlds made of rock or ice or gas.
If the spacecraft does reach its target – an asteroid named Psyche — it could help scientists understand how violent collisions and events in the solar system's early years led to the formation of planets that have metal-rich cores, including Earth.
Psyche was discovered back in 1852. It's about the size of Massachusetts and likely shaped like a potato, says Elkins-Tanton. Because it's unusually dense, researchers believe around 30 to 60 percent of it is metal.
"We do not know what Psyche looks like," says Elkins-Tanton, but the spacecraft should send images back once it arrives at the asteroid in August of 2029. The probe, which is named after Psyche, will blast off from Kennedy Space Center in Florida on a SpaceX rocket, and its first opportunity to launch comes Thursday morning at 10:16 a.m. EDT.
Researchers believe the asteroid might have craters that are ringed with iron spikes, says Elkins-Tanton, because an impact might send up streams of molten metal that then solidify. The asteroid might also have huge metal cliffs, and the remnants of greenish-yellow lava flows.
NASA/JPL-Caltech/ASU
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This artist's conception shows what a metal-rich asteroid like Psyche might look like, but scientists really aren't sure what they'll see.
NASA/JPL-Caltech/ASU
This artist's conception shows what a metal-rich asteroid like Psyche might look like, but scientists really aren't sure what they'll see.
NASA/JPL-Caltech/ASU
For now, all planetary scientists can do is imagine, because telescopes see the asteroid as just a point of light. At its closest approach to Earth, Psyche is over 150 million miles away, in the outer part of the main asteroid belt that lies between Mars and Jupiter.
Since asteroids are leftovers from when the planets formed, Elkins-Tanton says Psyche is like an exposed version of what lurks at the center of rocky planets.
"We're trying to understand about the metal core of the Earth," she says, noting that Mars and Venus and Mercury also have metal cores. "We are never, ever going to go to those cores — way too hot, way too deep — so this is our one way to see a core."
There are other metallic asteroids that represent this kind of planetary building block, she says, "but Psyche is by far the largest, and the one that is most likely to tell us the most about cores."
The planet Mercury has an unusually high amount of iron beneath a rocky shell, and there are some planets outside the solar system, around distant stars, that also seem to mostly be made of metal, says Ben Weiss of MIT, the deputy principal investigator for the mission.
So even though Psyche's metal-rich nature makes it an unusual asteroid, he says, "it's also kind of representative of a diverse range of bodies that we think are maybe metal worlds."
Unlike NASA's recent OSIRIS-REx mission, this effort will not return a sample of the asteroid.
"Because we don't know what its surface looks like, we're not ready to land. We're not ready to sample," says Elkins-Tanton. "We have to have some sense of what this object is like before we can take that next step." | Chemistry and Material Sciences |
Study sheds new light on strange lava worlds
Lava worlds, massive exoplanets home to sparkling skies and roiling volcanic seas called magma oceans, are distinctly unlike the planets in our solar system.
To date, nearly 50% of all rocky exoplanets yet discovered have been found capable of maintaining magma on their surfaces, likely because these planets are so close to their host stars they orbit in fewer than 10 days. Being so close causes the planet to be bombarded by harsh weather and forces surface temperatures to the extreme, making it all but completely inhospitable to life as we know it today.
Now, in a new study, scientists have shown that these sweeping molten oceans have a large influence on the observed properties of hot rocky Super-Earths, such as their size and evolutionary path.
Their research, published recently in The Astrophysical Journal, found that due to lava's extremely compressible nature, oceans of magma can cause lava-rich planets without atmospheres to be modestly denser than similarly sized solid planets as well as impact the structure of their mantles, the thick inner layer that surrounds a planet's core.
Even so, since these objects are notoriously under-studied, it can be a difficult task to characterize the fundamental workings of lava planets, said Kiersten Boley, lead author of the study and a graduate student in astronomy at The Ohio State University.
"Lava worlds are very odd, very interesting things and because of the way we detect exoplanets, we're more biased to finding them," said Boley, whose research revolves around understanding what essential ingredients makes exoplanets unique and how tweaking those elements, or in the case of lava worlds, their temperatures, can completely change them.
One of the most well-known of these mysterious burning worlds is 55 Cancri e, an exoplanet about 41 light-years away that scientists describe as home to both sparkling skies and roiling lava seas.
While there are objects in our solar system, such as Jupiter's moon Io, that are extremely volcanically active, there aren't true lava planets in our stretch of the cosmos that scientists can get up close and personal to study. However, investigating how the composition of magma oceans contributes to the evolution of other planets, such as for how long they stay molten and for what reasons they eventually cool down, can offer clues into Earth's own fiery history, said Boley.
"When planets initially form, particularly for rocky terrestrial planets, they go through a magma ocean stage as they're cooling down," said Boley. "So lava worlds can give us some insight into what may have happened in the evolution of nearly any terrestrial planet."
Using the exoplanet interior modeler software Exoplex and data collected from previous studies to construct a module that included information on several types of magma compositions, researchers simulated several evolutionary scenarios of an Earth-like planet with surface temperatures from between 2600 and 3860 degrees Fahrenheit—the melting point at which the planet's solid mantle would turn to liquid.
From the models they created, the team was able to discern that mantles of magma ocean planets can take on one of three forms: the first in which the entire mantle is completely molten, the second where a magma ocean lies on the surface, and a third sandwich-esque model that consists of a magma ocean at the surface, a solid rock layer in the middle and another layer of molten magma that lies closest to the planet's core.
The results suggest that the second and third forms are slightly more common than planets that are completely molten. Depending on the composition of magma oceans, some atmosphere-free exoplanets are better than others at trapping volatile elements—compounds such as oxygen and carbon necessary to the formation of early atmospheres—for billions of years.
For example, the study notes that a basal magma class planet that is 4 times more massive than Earth can trap more than 130 times the mass of water than in Earth's oceans today, and about 1,000 times the amount of carbon currently present in the planet's surface and crust.
"When we're talking about the evolution of a planet and its potential to have different elements that you would need to support life, being able to trap a lot of volatile elements within their mantles could have greater implications for habitability," said Boley.
Lava planets are a long way from becoming habitable enough to support life, but it's important to understand the processes that help these worlds to get there. Nevertheless, this study makes clear that measuring their density isn't exactly the best way to characterize these worlds when comparing them to solid exoplanets as a magma ocean neither significantly increases nor decreases its planet's density, said Boley.
Instead, their research reveals that scientists should focus on other terrestrial parameters such as fluctuations in a planet's surface gravity to test their theories about how hot lava worlds operate, especially if future researchers plan on using their data to aid in larger planetary studies.
"This work, which is a combination of earth sciences and astronomy, basically opens up exciting new questions about lava worlds," said Boley.
More information: Kiersten M. Boley et al, Fizzy Super-Earths: Impacts of Magma Composition on the Bulk Density and Structure of Lava Worlds, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/acea85
Exoplex: github.com/amloren1/ExoPlex
Journal information: Astrophysical Journal
Provided by The Ohio State University | Chemistry and Material Sciences |
On the morning of Oct. 12, if everything goes to plan, NASA will be sending a high-tech spacecraft called Psyche on a 2.2 billion mile journey to an intriguing asteroid by the same name. Well, to be clear, the asteroid is known as 16 Psyche.
The goal of the Psyche mission is to study this space rock in great detail because not only is it believed to be very metal-rich, but it's also speculated to really be the leftover iron core of what once was a whole planet. And potentially, Earth's core is made of similar stuff — which means 16 Psyche could be offering us a direct tunnel to the center of our world, a place we cannot otherwise reach.
But before this mission starts falling into place, scientists are using other mechanisms to study the 140-mile-wide space rock. This way, we might know what's in store for NASA's craft upon arrival in 2029. In fact, one team from the Southwest Research Institute recently announced some results they gleaned about the asteroid. These are results they collected by tapping into two powerful infrared instruments: The presently trailblazing James Webb Space Telescope (JWST) and the now-retired Stratospheric Observatory for Infrared Astronomy (SOFIA). Infrared sensors, unlike standard optical sensors, are able to observe data in the infrared region of the electromagnetic spectrum. Light associated with this region is, in essence, invisible to the human eye. We can only see a teeny portion of the spectrum known as, naturally, the visible region. But this is why infrared astronomy is so important — it can help reveal pieces of the universe normally hidden to us and our regular old telescopes.
However, though data from these tools offered a significant-enough lens into 16 Psyche, perhaps the most thought-provoking finding was that they both reached a limit.
"All of the observations using different techniques keep showing us results that don't make sense in context with each other," Anicia Arredondo, a postdoctoral researcher at the SwRI and first author of a paper on the findings, said in a statement. "That's why it's so important that we have a mission going there now.”
"With this analysis and the previous studies of Psyche, we have reached the limit of what astronomical observations can teach us about this fascinating asteroid," Maggie McAdam, a NASA Ames research scientist and principal investigator of the new study, said in a separate statement.
But they did find something. Sort of.
To begin, the team observed 16 Psyche in early 2022 with SOFIA — a flying observatory that's essentially a Boeing 747 aircraft carrying a reflective telescope.
SOFIA, which stopped operations that same year due to its high operating costs, was able to scan the asteroid in the infrared range as the space rock rotated. In doing so, the telescope gathered information that the scientists say they can use to understand whether Psyche is the remnant core of a differentiated asteroid — an asteroid that underwent major chemical or physical changes — or a protoplanet.
"If so," Arredondo said, "multiple impacts would have stripped all the outer layers off, leaving only a metal core. But those impacts could also lead to variability. However, observations indicate that Psyche is metal — no big surprise — and we don’t see a lot of variation with rotation, at least at the mid-infrared wavelengths."
In a nutshell, the reason the team realized Psyche is most likely metal is that SOFIA's spectral data (a graph of different forms of light emitted by the asteroid) didn't have any spikes. It also didn't have a feature known as the 10-micron plateau. These are things that suggest the presence of rock, the team says, such as ground resembling a "fluffy" regolith.
The JWST, on the other hand, helped the team determine whether water exists on the asteroid. "Observations across the 3- and 6-micron wavelength ranges tell us whether hydration is present in the form of hydroxyl or actual water," Stephanie Jarmack, a research scientist at SwRI and member of the study team, said in the statement — hydroxyl referring to a molecule that consists of one oxygen atom and one hydrogen atom.
"If we don’t find it," Jarmack continued, "that wouldn’t be surprising, considering Psyche is thought to be a mostly metallic world." But now, the team says, we'll have to wait until Psyche gets to Psyche in 2029 and starts employing its own technologies meant to study the elusive space rock.
For instance, the 6,056-pound (2,747 kilograms) explorer carries a multispectral imager that can photograph the asteroid in visible light wavelengths and near-infrared wavelengths; it has a gamma-ray and neutron spectrometer that can help reveal chemical elements that make up the rock's surface; and a magnetometer that will look for proof of an ancient magnetic field on the subject. And that's not even all of it.
"We need to physically visit Psyche to study it up close and learn more about what appears to be a very unique planetary body," McAdam said. | Chemistry and Material Sciences |
Data from a meteorite impact on Mars that was recorded by NASA’s InSight lander in 2021 is now helping to clear up some confusion about the red planet’s interior makeup. A pair of studies published today in the journal Nature separately determined that Mars’ iron-rich core is smaller and denser than previous measurements suggested, and it’s surrounded by molten rock.
The now defunct InSight lander, which arrived on Mars in November 2018, spent four years recording seismic waves produced by marsquakes so scientists could get a better understanding of what’s going on beneath the planet’s surface. But, estimates of the Martian core based on InSight’s initial readings from nearby quakes didn’t quite add up. At the time, scientists found the core’s radius to be somewhere between 1118 and 1149 miles — much larger than expected — and that it contained a perplexingly high amount of lighter elements complementing its heavy liquid iron.
The numbers for those light elements were “bordering on the impossible,” said Dongyang Huang of ETH Zurich, a co-author of one of the studies. “We have been wondering about this result ever since.” Then, a breakthrough came when a meteorite struck Mars in September 2021 all the way across the planet from where InSight is positioned, generating seismic waves that ETH Zurich doctoral student Cecilia Duran said “allowed us to illuminate the core.”
Based on those measurements, the two teams have found that Mars’ core more likely has a radius of about 1013-1060 miles. This, the ETH Zurich team notes, is about half the radius of Mars itself. A smaller core would also be more dense, meaning the previously inexplicable abundance of light elements may actually exist in smaller, more reasonable amounts. This is all surrounded by a layer of molten silicates about 90 miles thick, the teams found, which skewed the initial estimates. And, it’s unlike anything found in Earth’s interior.
According to Vedran Lekic from University of Maryland, a co-author of the second paper, the layer serves as somewhat of a “heating blanket” for the core that “concentrates radioactive elements.” Studying it could help scientists uncover answers about Mars’ formation and its lack of an active magnetic field. | Chemistry and Material Sciences |
The OSIRIS-REx canister still contains the bulk of the asteroid sample inside, but pieces of the ancient space rock found on the outside have already shown evidence of organic matter embedded within tiny bits of debris.
On Wednesday, NASA revealed the first look at samples returned from asteroid Bennu through its OSIRIS-REx mission. Scientists performed an early analysis of the asteroid sample and found an abundance of carbon and water molecules, supporting the theory that the building blocks of life may have made their way to Earth via asteroids.
“This is the biggest carbon-rich asteroid sample returned to Earth,” NASA Administrator Bill Nelson said during the event at the Johnson Space Center in Houston. “Carbon and water molecules are exactly the kinds of material that we wanted to find, crucial elements in the formation of our own planet and they’re going to help us determine the origin of elements that could have led to life.”
The samples were dropped off to Earth in late September, with the OSIRIS-REx return capsule performing a parachute-assisted landing in the Utah desert after traveling through space for nearly three years. A curation team has been carefully disassembling the TAGSAM (Touch-and-Go Sample Acquisition Mechanism) head to get to the bulk of the sample.
Although they haven’t even opened the sample canister yet, extra bits of the asteroid were found outside TAGSAM—an articulated arm on the spacecraft with a round sampler head at the end used to grab the sample. The entire sample far exceeded NASA’s goal of collecting 60 grams from the surface of Bennu. What’s been revealed so far from the bonus sample is “a combination of fine dust, as well as some of what we call intermediate sized particles,” Nicole Lunning, OSIRIS-REx Lead Curator, said on Wednesday.
In order to fully preserve the asteroid debris on the outside, it’s taking the team more time to open the canister. “The only problem is a great problem and that’s we’ve found a lot more sample than we’re anticipating before even getting into the TAGSAM,” Francis McCubbin, curator at NASA’s JSC, said at the event. “Because we need to very meticulously and carefully collect every grain, it’s taking us a little longer to get inside, but the view so far is amazing.”
Over the past two weeks, the team has been analyzing some of the bonus sample using an electron microscope, infrared measurements, X-ray diffraction, and chemical element analysis. The collected sample so far is 4.7% carbon by weight, making it the highest abundance of carbon ever measured in an extraterrestrial sample, according to Daniel Glavin, OSIRIS-REx sample analyst. It also contains abundant water in the form of hydrated clay minerals.
“We picked the right asteroid,” Glavin said. “And not only that, we also picked the right sample—this is an astrobiologist’s dream.”
Bennu is a small, near-Earth asteroid that makes a close pass to Earth every six years or so. Scientists believe Bennu might have broken off from a much larger carbon-rich asteroid about 700 million to 2 billion years ago and drifted much closer to Earth since then. Analyzing bits of the asteroid in a lab will help scientists piece together clues on the origins of the solar system. Bennu is also a near-Earth potentially hazardous asteroid, therefore studying it closely can help us learn more about its potential threats to our planet.
The OSIRIS-REx mission launched in September 2016 and reached asteroid Bennu in December 2018. After nearly two years of observations, the spacecraft landed on Bennu and snagged a sample from its surface in October 2020. On May 10, 2021, OSIRIS-REx said goodbye to Bennu and began its journey back home to drop off its precious cargo.
Once the samples touched down on Earth, the work on the ground was only just beginning. The sample analysis team is made up of 230 scientists around the world, and returned pieces of the asteroid will be allocated to different teams to perform in-depth analysis of Bennu’s composition. NASA will keep at least 70% of the sample at Johnson Space Center for future research to take place decades from now, hoping to take advantage of advanced technology in the coming years.
Some of the asteroid bits will also be made available for public display at the Smithsonian Institution, Space Center Houston, and the University of Arizona. | Chemistry and Material Sciences |
Osiris-Rex: NASA reveals evidence of water and carbon in sample delivered to Earth from an asteroid
On September 24 this year, a NASA capsule parachuted down to Earth carrying a precious cache of material grabbed from an asteroid. The space agency has now revealed images and a preliminary analysis of the space rocks it found after lifting the lid off that capsule.
The mission to the asteroid was called Osiris-Rex, and in 2020, it collected a sample of material from the asteroid Bennu. Afterward, it traveled back to Earth and released the capsule containing the rocks into our atmosphere three weeks ago.
The fine black dust and small coal-like rocks shimmering in the capsule are beautiful—and somewhat unassuming. But this handful of space rock has the potential to answer questions about not only how the Earth was created, but also how water arrived here and how life got started.
At the NASA press conference on October 11 held to reveal details about the sample, Dr. Francis McCubbin hinted that, with careful storage and preparation, the material could be analyzed and used in experiments for years to come.
"Scientists that aren't even born yet, (will be able to) answer questions about the universe using technology that has not even been invented," said the astromaterials curator at NASA's Johnson Space Center, Houston, where the Bennu sample is being stored.
Why collect asteroid samples?
Sometimes material from space comes to Earth without our help, arriving as meteorites. NASA has hundreds of meteorite samples in its collection, which are believed to have come from asteroids. Useful analysis can be carried out on these samples.
However, it's often not possible to track down which asteroids these meteorites came from. This limits the potential of the resulting science. Meteorites are also contaminated by their journey through the atmosphere and onto the Earth. The Osiris-Rex sample, in contrast, is "pristine." We can be sure any discoveries made from this sample tell us about Bennu.
Some of the finer dust in the Bennu sample would never have been able to form a meteorite and fall to Earth. Going and retrieving it is the only way we would ever have seen this type of material.
This is not the first asteroid sample delivered to Earth. Two Japanese space agency (Jaxa) missions, Hayabusa 1 and 2, made deliveries of asteroid material in 2010 and 2020. However, this is the first US mission to do so. It also returned with significantly more material than the Hayabusa missions.
Osiris-Rex delivered an estimated 250g of material, compared to Hayabusa 2's 5g. This means the sample can be distributed to scientists around the world and put on display in museums for the public to enjoy. It also means that some larger rock fragments were included, which gives a unique opportunity to examine how different minerals are arranged in bigger chunks of the asteroid. This unlocks even more scientific potential.
What have they found?
Bennu is what is known as a "carbonaceous," or C-Type, asteroid. These contain a large proportion of carbon and "volatiles"—compounds that can be readily vaporized, like water. These asteroids are believed to be relics from the formation of the solar system, and so can help explain how the planets, including Earth, came to be.
Analysis of the main portion of the sample has taken longer than expected to get started, but it's a nice problem to have. The sample collection technique was so successful that the sample was "spilling out" of the container within the return capsule. Because every grain is precious, all of this bonus material must be meticulously collected before the sample canister itself can be opened and preparation of the main body of the sample can begin.
Still, there have already been some exciting results from the initial analysis. Water has been found locked inside clay minerals from Bennu, which is an incredibly important discovery. One proposed mechanism for how water came to be on Earth and the other inner planets is that water was trapped inside clay minerals like these, which then formed into rocks that eventually formed planets during the birth of the solar system.
There's abundant carbon in the sample—nearly 5% by weight—and sulfur. Both elements are essential for life. Carbon is the key ingredient in the organic compounds that make biology possible. Sulfur is an important component of amino acids, which form proteins.
Asteroids like Bennu are thought to have "seeded" Earth with prebiotic compounds: the building blocks of life. Magnetite (an iron oxide) found in the sample has been linked to chemical reactions crucial for the evolution of life. As Dr. Daniel Glavin, Osiris-Rex sample analyst, summarized: "We picked the right asteroid. And not only that, we brought back the right sample."
What next?
As well as helping answer the big questions of how we and our planet came to be here, finding water on asteroids is also destined to be a part of our future. Water can be broken down into hydrogen and oxygen, which can then be used as rocket fuel. While still some way off, spaceship refueling stations are moving out of the realms of science fiction and into reality.
There's only so much fuel you can take with you on a rocket. Far better to take just what you need to get off the planet and then fuel up in space for the rest of your journey.
Water can also be used for life support in future bases on the moon and Mars. So it's crucial to understand where we can access water in space, and how to extract it. The water on asteroids is one potential source.
Asteroids, once known best for their likely part in the demise of dinosaurs, are enjoying some positive time in the spotlight, showcasing their part in humanity's past, present and future.
Provided by The Conversation | Chemistry and Material Sciences |
Jupiter’s orbit is swarming with nearly 100 moons, but none are as hardcore as the volcanic world Io. That’s why it’s going to take an iconic collaboration to truly probe the odd satellite in order to unravel its many mysteries.
The Southwest Research Institute (SwRI) will use the Hubble and James Webb telescopes to simultaneously observe Io from a distance as the Juno spacecraft swings by Jupiter’s moon for a series of flybys over the next year.
“The timing of this project is critical,” Kurt Retherford, principal investigator of the campaign at SwRI, said in a statement. “The combination of Juno’s intensive in situ measurements with our remote-sensing observations will undoubtedly advance our understanding of Io’s role in driving coupled phenomena in the Jupiter system.”
Io is the most volcanically active body in the Solar System, with hundreds of volcanoes and lakes of molten silicate lava on its surface. The moon is wedged between Jupiter’s immense gravitational force, as well as the gravitational tug of its sister moons Europa and Ganymede. As a result, the moon is constantly being stretched and squeezed, which contributes to its volcanic activity.
As the innermost of Jupiter’s large moons, Io is the main source of most of the charged particles in the planet’s magnetosphere, creating a donut-shaped cloud of ions and electrons that surround Jupiter. The cloud, known as Io Plasma Torus, is formed when atmospheric gases escaping from Io are ionized.
“We hope to gain new insights into Io’s dramatic volcanism, plasma-moon interactions and the neutral gas and plasma populations that propagate through Jupiter’s vast magnetosphere and trigger intense Jovian auroral emissions,” Retherford said.
NASA’s Juno spacecraft, which has been studying the Jovian system since 2016, observed Io during previous flybys in May and July. The next time Juno approaches the volcanic world will be on December 30, as well as February 1, 2024, and then again on September 20, 2024. During those upcoming flybys, scientists will have the opportunity to gather data provided by Juno combined with remote observations by Hubble and Webb.
“The combination of Juno’s intensive [on site] measurements with our remote-sensing observations will undoubtedly advance our understanding of Io’s role in driving coupled phenomena in the Jupiter system,” Retherford said. | Chemistry and Material Sciences |
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Astronomers using the James Webb Space Telescope have for the first time detected tiny quartz crystals containing silica — a common mineral on Earth — within the atmosphere of a blazing hot exoplanet.
It’s likely that the nanoparticles of silica, which on Earth appears in beach sands and is used to produce glass, swirl from the clouds of the exoplanet, known as WASP-17b, according to the researchers.
First discovered in 2009, WASP-17b is a gas giant planet located 1,300 light-years from Earth. It has a volume more than seven times that of Jupiter, making it one of the largest exoplanets known to astronomers.
The researchers detected the the quartz nanoparticles in high-altitude clouds using Webb’s Mid-Infrared Instrument, according to new research published Monday in The Astrophysical Journal Letters.
“We were thrilled,” said lead study author David Grant, a researcher at the University of Bristol, in a statement. “We knew from Hubble observations that there must be aerosols — tiny particles making up clouds or haze — in WASP-17 b’s atmosphere, but we didn’t expect them to be made of quartz.”
Minerals rich in silicon and oxygen, called silicates, are plentiful on Earth, the moon and other rocky bodies in the solar system. Silicates are also incredibly common in the Milky Way galaxy. But so far, the silicate grains detected in exoplanet atmospheres have been magnesium-based, not quartz, which is made of pure silica.
“We fully expected to see magnesium silicates,” said study coauthor Hannah Wakeford, senior lecturer in astrophysics at University of Bristol, in a statement.
“But what we’re seeing instead are likely the building blocks of those, the tiny ‘seed’ particles needed to form the larger silicate grains we detect in cooler exoplanets and brown dwarfs.”
The finding could enable researchers to understand the materials used to form planetary environments much different from what we know on Earth.
What the quartz crystals reveal about WASP-17b
Wasp-17b takes 3.7 Earth days to complete one orbit around its star. Astronomers focused their observations on the exoplanet as it crossed in front of its star and starlight filtered through its atmosphere.
After 10 hours of observation time, the team discovered a signature suggesting the presence of quartz nanoparticles.
The quartz crystals are likely hexagonal in shape, like the much larger geodes we know on Earth, but each one is only one-millionth of a centimeter — so small that 10,000 of the grains could fit side by side across a human hair, according to the research. And the particles originate in the atmosphere.
“WASP-17 b is extremely hot — around 2,700 degrees Fahrenheit (1,500 degrees Celsius) — and the pressure where the quartz crystals form high in the atmosphere is only about one-thousandth of what we experience on Earth’s surface,” Grant said. “In these conditions, solid crystals can form directly from gas, without going through a liquid phase first.”
The planet is tidally locked to its star, meaning one side always faces the star and experiences searing temperatures, while the permanent “night” side of the planet is cooler. While the clouds can drift around the planet, they likely vaporize on the hot day side, which could send the quartz particles swirling.
“The winds could be moving these tiny glassy particles around at thousands of miles per hour,” Grant said.
Webb’s sensitive detections are allowing researchers to have a better understanding of the atmospheres, environmental conditions and weather on planets outside of our solar system.
Hot gas giants, also called Hot Jupiters, like WASP-17b are largely composed of hydrogen and helium, along with some water vapor and carbon dioxide. Detecting silica in the planet’s atmosphere helps scientists to have a broader sense of WASP-17b’s composition.
“If we only consider the oxygen that is in these gases, and neglect to include all of the oxygen locked up in minerals like quartz, we will significantly underestimate the total abundance,” Wakeford said. “These beautiful silica crystals tell us about the inventory of different materials and how they all come together to shape the environment of this planet.” | Chemistry and Material Sciences |
Astronomers announced the discovery of the first-ever 'boomerang meteorite' - a rock that originated from Earth, was ejected into space and later returned.
The meteorite, NWA 13188, was uncovered in the Sahara Desert, and scientists at Aix-Marseille University in France conducted a new analysis, finding it has characteristics of our planet.
The object has composition found in Earth's crust and volcanic rock, but also elements that only appear when exposed to energetic cosmic rays in space.
Researchers believe the rock was propelled into space by an asteroid impact around 10,000 years ago.
Meteorite hunters uncovered the rock in question in 2018 in Morocco, which led scientists to name it Northwest Africa (NWA).
The analysis, led by Jérôme Gattacceca, determined the rock has an 'overall basaltic andesite composition' found in volcanic rock across the globe.
It is also dominated by plagioclase, an aluminum-bearing mineral and pyroxene, a dark-colored for-forming mineral, which scientists said has raised the debate that the 'space rock' is not a meteorite at all.
However, some elements have been altered into light forms, which is only possible if the rock interacts with cosmic rays in space.
One clue the rock ventured back to Earth from space is the measured concentrations of these altered elements, known as isotopes, are too high to be accounted for by Earth-bound processes.
Gattacceca and his team found detectable isotopic imprints like beryllium-3, helium-10 and neon-21 in NWA 13188, Space.com reports.
Researchers also identified a fusion crust coating on the rock, which forms when meteorites soar through Earth's atmosphere and travel to the ground.
'Therefore, we consider NWA 13188 to be a meteorite, launched from the Earth and later re-accreted to its surface,' Gattacceca shared in a statement.
'This scenario matches the latest definition of meteorites: 'Material launched from a celestial body that achieves an independent orbit around the Sun or some other celestial body, and which eventually is re-accreted by the original body, should be considered a meteorite.
''The difficulty, of course, would be in proving that this had happened, but a terrestrial rock exposed to cosmic rays and with a well-developed fusion crust should be considered a possible terrestrial meteorite.'' | Chemistry and Material Sciences |
Researchers report on the atmosphere of hot Jupiter HD 189733b
Scientists from the Institute of Laser Physics of the Siberian Branch of the Russian Foundation for Basic Research have modeled the atmosphere of the well-known "hot Jupiter" HD 189733b and have learned what hindered a stable finding of hydrogen in the atmosphere of the planet. They also defined the physico-chemical properties of this planetary system. They presented on this topic at the symposium of Asian Pacific Geophysical Society in August 2023, and the work is published in The Astrophysical Journal.
Exoplanets are planets beyond the solar system. The most studied of them are from the family of so-called hot Jupiters. They can be compared with Jupiterian exoplanets as far as size and weight is concerned, but orbit their stars 10 times nearer than Mercury orbits the sun.
Such close distance and high temperatures cause atmosphere to escape from planets with ultrasonic speed, and the movement of the atmosphere, and also its content, can be studied with the help of method of transit spectroscopy. This method consists of registration of absorptions of stellar radiation by the planet's atmosphere and enables definition of which elements are present in the atmosphere, allowing researchers to make conclusions about speed and density of various elements.
HD 189733b has attracted researchers and observation time of telescopes for less than a decade. The planet became popular due its blue color, caused by glass (silicate) rains—particles of silicates raised into the atmosphere. One of the most interesting mysteries of this planet was "disappearing" transit in the hydrogen line Lyα—measurements of absorptions in this diapason of wavelength turned out to be rather inconsistent.
A bit clearer is the situation with the IK-line of metastable helium 1083 nm—transit in its locality was observed twice, but with different amplitude. Such changes suggest substantially different regimes of the outflow of planetary matter of HD 189733b, and computer modeling is the most available way of investigating possible causes of changes.
One of the most advanced instruments for modeling of complex of features in the atmosphere of exoplanets and interpretation of transit absorptions in the world was created and developed by scientists from the Institute of Laser Physics of the Siberian Branch of the Russian Foundation for Basic Research.
Having applied it to HD 189733b, scientists found that the most probable cause of unstable absorptions in the hydrogen line Lyα is high activity of the host star, which appears in an increase of radiation flux in the ultraviolet area (FXUV, erg∙cm-2с-1Å-1 for 1 АЕ) and the speed of loss of mass of stellar material. It was discovered that changes in those factors can cause not only variable detections of transit absorption in the hydrogen line due to formation of energetically neutral atoms in strong stellar wind, but also different absorptions in the line of metastable helium.
More information: M. S. Rumenskikh et al, Global 3D Simulation of the Upper Atmosphere of HD189733b and Absorption in Metastable He i and Lyα Lines, The Astrophysical Journal (2022). DOI: 10.3847/1538-4357/ac441d
Journal information: Astrophysical Journal
Provided by Russian Foundation for Basic Research | Chemistry and Material Sciences |
India's Chandrayaan-3 mission successfully landed near the moon's south pole on Wednesday (Aug. 23). The Indian Space Research Organization (IRSO) mission not only made history because it saw the nation become the fourth to successfully land on the moon — after the Soviet Union, the U.S. and China — but also because it named India the first to land at the southern lunar pole.
But IRSO's mission, which has since deployed a robotic rover to begin exploring the lunar south pole, isn't exactly alone in its goals.
Around 2025, as part of its Artemis 3 mission, NASA plans to have humans step foot on the moon for the first time in 50 years. That journey is also set to include the first woman and person of color to make the trip. But even before that, the U.S. space agency's Volatiles Investigating Polar Exploration Rover (VIPER) is expected to explore the southern pole in 2024 during a 100-day-long mission.
And China, with its burgeoning space industry, isn't going to be left out of this lunar south pole action. The country's space agency plans to send the Chang'e 7 mission there in 2026 along with a new moon rover.
So why is all this interest in the lunar south pole heating up? Well, ironically, it's primarily due to something very cool.
The lunar south pole's most precious commodity
Interest in the lunar south pole as a landing site is mainly driven by the fact that scientists know the region hosts water in the form of ice. Water is, of course, essential for life as we know it — but it also has other uses. For instance, it can act as a coolant for equipment and even provide rocket fuel. The latter could be especially useful for a staging mission to Mars launched from the moon someday.
What this means is, as space agencies start thinking about sustainability in space as well as the next era of crewed space missions, the ability to harvest water in-situ on the moon for drinking, cooling machinery, or even breaking down into hydrogen and oxygen to provide breathable air or fuel is of immense value.
Additionally, water on the moon is of pure scientific value. It can be used as a record of geological activity on the moon, such as lunar volcanoes, and even act as an asteroid strike tracker.
While water has been detected across the surface of the moon, the majority of water ice signals come from the poles.
At the lunar south pole, only elevated peaks are lit by the sun. This is because the sun is always positioned around the horizon due to the moon's tilt. More low-lying areas are permanently shrouded in shadow, and are quite literally referred to as permanently shadowed regions (PSRs).
Temperatures in PSRs can drop to as low as -418 degrees Fahrenheit (-250 degrees Celsius), which is so frigid its colder than Pluto — but this means it's also an ideal spot to maintain water ice.
Any water molecules that enter a PSR region are immediately frozen. They're also trapped because it is simply too cold for them to evaporate. This water content then falls to the surface, where it gets mixed with lunar soil. That process results in the growth of large "pockets" of water and soil at the moon's south pole.
ISRO was integral in first detecting such lunar water to begin with when, in 2008, its Chandrayaan-1 spacecraft carried a NASA-provided science instrument called the Moon Mineralogical Mapper (M3) to lunar orbit. This determined the existence of water ice inside craters at the moon's south pole.
The following year, in 2009, NASA's Lunar Reconnaissance Orbiter (LRO) purposefully slammed a dark crater at the lunar south pole with the Lunar Crater Observation and Sensing Satellite (LCROSS). This created a plume of debris that LCROSS jetted through, enabling it to detect water ice that had been hidden in darkness.
There was a small concern, however, that the molecule hydroxyl (OH) was confused to be the water molecule (H2O). This fear was allayed in 2020 when it was revealed that data from NASA's Stratospheric Observatory For Infrared Astronomy (SOFIA) telescope confirmed the first unambiguous detection of water at the lunar south pole.
Based upon SOFIA data, scientists estimated there could be as much as 12 ounces of water for every one cubic meter (just over 35 cubic feet) of lunar soil at the southern pole of the moon.
According to the Planetary Society, when considering Chandrayaan-1 and LRO data, the two lunar poles harbor over 600 million tons of water ice. That's enough to fill around 240,000 Olympic-sized swimming pools.
And this, experts say, is a low-end estimate.
Thus, with such an incredibly valuable resource located around the lunar south pole, it is a wonder space agencies haven't already swarmed to get some space probes there well before ISRO's Chandrayaan-3 mission soft-landed this week.
As it turns out, there is a very good reason for this.
Why haven't we landed at the lunar pole before?
Landing near the lunar south pole is not easy, and part of the reason for this is tied to what makes landing there so desirable in the first place. The shadowy nature of the lunar south pole that helps preserve water ice means a soft landing there is tricky.
Most lunar descent vehicles rely on cameras to guide their final approach to the lunar surface, ensuring to avoid obstacles and hazards such as boulders or craters.
Landing is is risky even on well-lit regions of the moon. Just one chance encounter between a boulder big enough to tip a spacecraft and a lander would end in disaster for the mission.
Therefore, the risk increases substantially in the shadowy lunar south pole.
Such risk, in fact, is also magnified by the fact that the lunar south pole lacks large expanses of flat terrain as are found at the moon's equator, for instance. Terrain at both lunar poles is known to be heavily cratered as well as more likely to be sloped and rocky.
Moreover, the south pole of the moon can't even be seen from Earth.
This means scientists' knowledge of it comes entirely from spacecraft orbiting the moon like the LRO, which has collected precise information about the region and its terrain.
Any lunar craft that seeks to land at the south pole must also be able to withstand the incredibly cold temperatures found there. Further, the lack of sunlight creating those temperatures delivers another issue, too: A lunar rover that strays into one of the many PSRs at the south pole of the moon will be out of contact with the sun, meaning it can't rely on solar power to operate and must instead have a nuclear power source.
As if all of that wasn't enough, PSRs are also out of the line of sight of Earth, meaning relaying messages to and from mission control in the shadowy regions is challenging to say the least.
Future missions like will take the mapping of the terrain of the lunar south pole to a whole new level, with the VIPER mission in particular hunting for resources that could be mined and exploited by the crew of the Artemis program.
Additionally, orbiters around the moon are scoping out the orb's perilous polar regions for suitable landing zones to limit, if not eliminate altogether, the risks of setting down without threatening mission failure.
And, to paint a picture of these are risks, there is at least one space-faring nation that has recently become all too aware of the turmoil that may happen at the lunar south pole.
Just days before the landing of Chandrayaan-3, Russia had planned to make its glorious return to the moon's surface after 47 years with Luna-25, which launched on Aug. 10. But on Aug. 19, Roscosmos announced via its Telegram feed that it had lost contact with the mission.
Luna-25 spacecraft had crashed into the moon's surface during landing preparations.
If it had been successful, Luna-25 would have hunted through the soil of the lunar south pole looking for water ice. “It’s hugely disappointing,” Open University planetary scientist Simeon Barber told Nature.
“It highlights that landing on the moon is not easy.” | Chemistry and Material Sciences |
weic2321 — Science Release
Webb discovers methane, carbon dioxide in atmosphere of K2-18 b
11 September 2023
A new investigation by an international team of astronomers using data from the NASA/ESA/CSA James Webb Space Telescope into K2-18 b, an exoplanet 8.6 times as massive as Earth, has revealed the presence of carbon-bearing molecules including methane and carbon dioxide. The discovery adds to recent studies suggesting that K2-18 b could be a Hycean exoplanet, one which has the potential to possess a hydrogen-rich atmosphere and a water ocean-covered surface.
The first insight into the atmospheric properties of this habitable-zone exoplanet came from observations with the NASA/ESA Hubble Space Telescope, which prompted further studies that have since changed our understanding of the system.
K2-18 b orbits the cool dwarf star K2-18 in the habitable zone and lies 120 light-years from Earth in the constellation Leo. Exoplanets such as K2-18 b, which have sizes between those of Earth and Neptune, are unlike anything in our Solar System. This lack of equivalent nearby planets means that these ‘sub-Neptunes’ are poorly understood, and the nature of their atmospheres is a matter of active debate among astronomers. Exoplanets such as K2-18 b, which have sizes between those of Earth and Neptune, are unlike anything in our Solar System. This lack of analogous nearby planets means that these ‘sub-Neptunes’ are poorly understood and the nature of their atmospheres is a matter of active debate between astronomers. The suggestion that the sub-Neptune K2-18 b could be a Hycean exoplanet is intriguing, as some astronomers believe that these worlds are promising environments to search for evidence for life on exoplanets.
"Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere," explained Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper announcing these results. "Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations."
The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be an ocean underneath a hydrogen-rich atmosphere on K2-18 b. These initial Webb observations also provided a possible detection of a molecule called dimethyl sulphide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments.
The inference of DMS is less robust and requires further validation. "Upcoming Webb observations should be able to confirm if DMS is indeed present in the atmosphere of K2-18 b at significant levels,” explained Madhusudhan.
While K2-18 b lies in the habitable zone and is now known to harbour carbon-bearing molecules, this does not necessarily mean that the planet can support life. The planet's large size — with a radius 2.6 times the radius of Earth — means that the planet’s interior likely contains a large mantle of high-pressure ice, like Neptune, but with a thinner hydrogen-rich atmosphere and an ocean surface. Hycean worlds are predicted to have oceans of water. However, it is also possible that the ocean is too hot to be habitable or be liquid.
"Although this kind of planet does not exist in our solar system, sub-Neptunes are the most common type of planet known so far in the galaxy," explained team member Subhajit Sarkar of Cardiff University. "We have obtained the most detailed spectrum of a habitable-zone sub-Neptune to date, and this allowed us to work out the molecules that exist in its atmosphere.”
Characterising the atmospheres of exoplanets like K2-18 b — meaning identifying their gases and physical conditions — is a very active area in astronomy. However, these planets are outshone — literally — by the glare of their much larger parent stars, which makes exploring exoplanet atmospheres particularly challenging.
The team sidestepped this challenge by analysing light from K2-18 b's parent star as it passed through the exoplanet's atmosphere. K2-18 b is a transiting exoplanet, meaning that we can detect a drop in brightness as it passes across the face of its host star. This is how the exoplanet was first discovered. This means that during transits a tiny fraction of starlight will pass through the exoplanet's atmosphere before reaching telescopes like Webb. The starlight's passage through the exoplanet atmosphere leaves traces that astronomers can piece together to determine the gases of the exoplanet's atmosphere.
"This result was only possible because of the extended wavelength range and unprecedented sensitivity of Webb, which enabled robust detection of spectral features with just two transits," continued Madhusudhan. "For comparison, one transit observation with Webb provided comparable precision to eight observations with Hubble conducted over a few years and in a relatively narrow wavelength range."
"These results are the product of just two observations of K2-18 b, with many more on the way,” explained team member Savvas Constantinou of the University of Cambridge. “This means our work here is but an early demonstration of what Webb can observe in habitable-zone exoplanets.”
The team now intends to conduct follow-up research with the telescope's Mid-InfraRed Instrument (MIRI) spectrograph that they hope will further validate their findings and provide new insights into the environmental conditions on K2-18 b.
"Our ultimate goal is the identification of life on a habitable exoplanet, which would transform our understanding of our place in the Universe," concluded Madhusudhan. "Our findings are a promising step towards a deeper understanding of Hycean worlds in this quest."
The team’s results are accepted for publication in The Astrophysical Journal Letters.
Notes
[1] The Habitable Zone is the region around a star where the conditions could potentially be suitable to sustain life on a planet within this region, for example allowing the presence of liquid water on its surface.
More information
Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona.
Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).
The international team of astronomers in this study consists of N. Madhusudhan, S.Sarkar, S. Constantinou, M. Holmberg, A. Piette, and J. Moses.
Image Credit: NASA, CSA, ESA, J. Olmstead (STScI), N. Madhusudhan (Cambridge University)
Links
- ESA Webb Seeing Farther Interactive Brochure
- Release on STScI website
- Release on ESA website
- Release on NASA website
- Release on University of Cambridge website
- Science paper
Contacts
Nikku (Madhu) Madhusudhan
Institute of Astronomy, University of Cambridge
Email: [email protected]
Bethany Downer
ESA/Webb Chief Science Communications Officer
Email: [email protected]
Ninja Menning
ESA Newsroom and Media Relations Office
Email: [email protected]
About the Release
|Release No.:||weic2321| | Chemistry and Material Sciences |
The breakup of supercontinents may trigger explosive eruptions that send fountains of diamonds shooting up to Earth's surface.
Diamonds form deep in Earth's crust, approximately 93 miles (150 kilometers) down. They are brought up to the surface very quickly in eruptions called kimberlites. These kimberlites travel at between 11 and 83 mph (18 to 133 km/h), and some eruptions may have created Mount Vesuvius-like explosions of gases and dust, said Thomas Gernon, a professor of Earth and climate science at the University of Southampton in England.
Researchers noticed that kimberlites occur most often during times when the tectonic plates are rearranging themselves in big ways, Gernon said, such as during the breakup of the supercontinent Pangaea. Oddly, though, kimberlites often erupt in the middle of continents, not at the edges of breakups — and this interior crust is thick, tough and hard to disrupt.
"The diamonds have been sat at the base of the continents for hundreds of millions or even billions of years," Gernon said. "There must be some stimulus that just drives them suddenly, because these eruptions themselves are really powerful, really explosive."
Gernon and his colleagues began by looking for correlations between the ages of kimberlites and the degree of plate fragmentation occurring at those times. They found that over the last 500 million years, there is a pattern where the plates start to pull apart, then 22 million to 30 million years later, kimberlite eruptions peak. (This pattern held over the last 1 billion years as well but with more uncertainty given the difficulties of tracing geologic cycles that far back.)
For example, the researchers found that kimberlite eruptions picked up in what is now Africa and South America starting about 25 million years after the breakup of the southern supercontinent Gondwana, about 180 million years ago. Today's North America also saw a spike in kimberlites after Pangaea began to rift apart around 250 million years ago. Interestingly, these kimberlite eruptions seemed to start at the edges of the rifts and then marched steadily toward the center of the land masses.
To figure out what was driving these patterns, the researchers used multiple computer models of the deep crust and upper mantle. They found that when tectonic plates pull apart, the base of the continental crust thins — just as the crust up top stretches out and forms valleys. Hot rock rises, comes into contact with this now-disrupted boundary, cools and sinks again, creating local areas of circulation.
These unstable regions can trigger instability in neighboring regions, gradually migrating thousands of miles toward the center of the continent. This finding matches the real-life pattern seen with kimberlite eruptions starting near rift zones and then moving to continental interiors, the researchers reported July 26 in the journal Nature.
But how do these instabilities cause explosive eruptions from deep in the crust? It's all in the mixing of just the right materials, Gernon said. The instabilities are enough to allow rock from the upper mantle and lower crust to flow against each other.
This churns together rock with lots of water and carbon dioxide trapped within it, along with many key kimberlite minerals — including diamonds. The result is like shaking a bottle of champagne, Gernon said: eruptions with a lot of explosive potential and buoyancy to drive them to the surface.
The findings could be useful in searching for undiscovered diamond deposits, Gernon said. They might also help explain why there are other types of volcanic eruptions that sometimes occur long after a supercontinent breakup in regions that should be largely stable.
"It’s a fundamental and highly organized physical process," Gernon said, "so it's likely not just kimberlites responding to it, but it could be a whole array of Earth system processes that are responding to this as well."
This story was originally published on Live Science. | Chemistry and Material Sciences |
For nearly twenty years, scientists have tracked puzzling signals from a massive planet known as '55 Cancri e.'
The fiery 'hell planet' — a so-called super-Earth nearly 40 light years away — can reach temperatures above 4,400 degrees Fahrenheit on its daylight side.
Soon, with help from the James Webb Space Telescope (JWST), researchers hope to fully decode those signals, proving whether or not the planet completely generates and sheds its own atmosphere under the intense heat of its parent star.
As the planet passes that star, Copernicus, scientists have recorded small eclipses and halos of Copernicus's own starlight as that light skims through 55 Cancri e's hellish atmosphere toward Earth.
A new theory of 55 Cancri e's evaporating and regenerating atmosphere, published this September, was developed after revisiting the records of those eclipses.
The researcher's new prediction: 'a thin, transient, secondary atmosphere' on 55 Cancri e, one that is belched out constantly by its ever-present volcanic activity.
After 55 Cancri e was discovered in 2004, scientists determined that it was likely to have volcanoes, flowing lava and high-speed winds carrying storms of 'raining' rock.
Even on its cooler night side, temperatures on 55 Cancri e hover at the blistering heat of molten rock, about 2,060 F.
The planet is 'likely so hot,' according to Lily Zhao of the Flatiron Institute's Center for Computational Astrophysics in New York, 'that nothing we're aware of would be able to survive on the surface.'
The new study used visible and infrared light collected from three separate space-based telescopes to model the gaseous make-up of this seemingly ever-changing atmosphere surrounding 55 Cancri e.
In essence, the hell planet's volcanoes are believed to regularly gush out hot gas, a process naturally called 'outgassing,' engulfing the whole planet in new layers of atmosphere.
But soon after, like clockwork, its sun's harsh radiation and solar winds strip 55 Cancri e of much of its extremely hot, new atmosphere.
But according to the new study's author, astrophysicist Kevin Heng of Ludwig Maximilian University in Germany, this churn of new atmosphere does not ever leave the planet entirely 'bald rock,' as past theories suggest.
'Despite this variability,' Heng wrote, 'its transit depth [the area of eclipsing planet to its eclipsed star] remains somewhat constant in time and is inconsistent with opaque material.'
In other words, even at its most 'bald' some atmosphere appears to remain, but only in visible via an infrared heat signature.
Heng detected evidence from three orbital telescopes, including the Spitzer Space Telescope and the CHEOPS space telescope, to suggest the possibility of a thin, ever-replenishing 'secondary atmosphere.'
'As the outgassed atmosphere escapes and is replenished,' Heng wrote, 'it rapidly adjusts to radiative equilibrium and the temperature fluctuations cause the infrared eclipse depths to vary.'
Heng's research — which has been accepted by the journal Astrophysical Journal Letters, but not yet peer reviewed — tested for the presence of various possible gases in 55 Cancri e's atmosphere to help confirm his hypothesis.
He found that carbon monoxide and carbon dioxide were more likely than methane.
'Atmospheres of pure methane are ruled out because they produce insufficient Rayleigh scattering,' Heng wrote.
Rayleigh scattering is the time-tested rules for how an atmosphere bends, dampens and generally reacts with light, named after the 19th-century British physicist Lord Rayleigh, who first formulated the principle.
According to past theories about the veritable hell world, when there is no blanket of gas surrounding 55 Cancri e, the planet only emits Infrared light.
Those scientists had previously predicted that when the atmosphere is present, then both the fluctuating visible light and infrared light would contribute to the transmitted signal.
But Heng's theory focused on the infrared light evidence to explore 'a proof of concept' mathematical model by which some thin, amount of atmosphere might always remain.
Astrophysicists, Heng included, are hoping that NASA's JWST can help them even more closely measure the changes in infrared and visible light coming off the 'hell planet' as it passes between Copernicus at the center of its solar system and telescopes here, closer to Earth.
The 'hell planet' is so close to its host star that it completes each new orbit in less than 20 hours, which may also contribute its unstable environment, but also means many transits and many eclipses from which to collect data.
'Upcoming observations by the James Webb Space Telescope,' Heng wrote in his new paper, 'will potentially allow the atmospheric temperature and surface pressure, as well as the surface temperature, to be measured.' | Chemistry and Material Sciences |
J. Robert Oppenheimer, now the protagonist of a much-anticipated film hitting theaters on July 21, is today most known for his scientific leadership of the U.S. Manhattan Project, the World War II–era crash program to build the first-ever atomic bombs. But just a few years earlier, Oppenheimer had found himself pondering very different “weapons” of mass destruction: black holes—although it would be decades before that name arose.
“It was influential; it was visionary,” says Feryal Özel, an astrophysicist at the Georgia Institute of Technology, of Oppenheimer’s work on black holes and neutron stars, the superdense corpses of expired massive stars. “He has a lasting impact.” Özel is a founding member of the Event Horizon Telescope Collaboration, which released the first-ever image of a black hole in 2019—80 years after Oppenheimer co-authored a paper theorizing that such objects could exist.
Özel isn’t the only leading modern physicist to admire Oppenheimer’s work on black holes. “It stands up completely; there are no flaws,” says Kip Thorne, an emeritus professor of physics at the California Institute of Technology. Thorne won the Nobel Prize in Physics in 2017 for his work with the Laser Interferometer Gravitational-Wave Observatory (LIGO), which in 2015 detected gravitational waves from two colliding black holes. “It went so far beyond anything that anybody else had ever done,” Thorne says of Oppenheimer’s “tour de force” paper exploring black holes, which runs only five pages long. “It is amazing what is contained there.”
Oppenheimer’s brief foray into astrophysics began with a 1938 paper about neutron stars, which continued in a 1939 installment that further incorporated the principles of Einstein’s general theory of relativity. He then published a third paper on black holes on September 1, 1939—but at the time, it was scarcely noticed because this was the very day Germany invaded Poland, launching World War II. Oppenheimer never wrote on the topic again.
Even if it hadn’t been overshadowed by war, Oppenheimer’s work on neutron stars and black holes “was not understood to be terribly significant at the time,” says Cathryn Carson, a historian of science at the University of California, Berkeley.
Each paper was written with a different member of the swarm of graduate students and postdoctoral scholars that Oppenheimer carefully cultivated. These protégés facilitated his ability to jump between research topics—and ultimately, according to Thorne and others, represent one of his most important contributions to physics.
Oppenheimer’s climactic third paper, written with his student Hartland Snyder, explores the implications of general relativity on the universe’s most massive stars. Although the physicists needed to include some assumptions to simplify the question, they determined that a large enough star would gravitationally collapse indefinitely—and within a finite amount of time, meaning that the objects we now know as black holes could exist.
“Eventually there should emerge what we would now call a singularity at the origin, a point of infinite density where, in some sense, spacetime itself rips, and there should become what we would now call an event horizon,” says David Kaiser, a physicist and historian of science at the Massachusetts Institute of Technology. “This is all in that paper—not in the modern vocabulary, but the mathematics is absolutely recognizable to us today.”
In the decades since Oppenheimer and Snyder’s black hole bombshell, scientists have confirmed that the same principles hold even without the simplifying assumptions initially put in place. Thorne says that the paper is particularly staggering, given contemporary work from an even more famous physicist—the one who developed general relativity in the first place.
“[Albert] Einstein published almost simultaneously a paper in which he argued that you cannot have a star or any object shrink to the size of what we now call the gravitational radius or the size of a black hole,” Thorne says. “Einstein was completely wrong.”
But despite the merit of Oppenheimer and Snyder’s work on black holes, the topic simmered on physicists’ back burner for decades—and today is perhaps best known as a sobering example of how brilliant ideas can be overlooked, says Manuel Ortega-Rodríguez, a theoretical physicist at the University of Costa Rica.
“It struck me as really, really interesting and fascinating and scary that such an idea was there for like 25 years, and nobody paid attention,” he says. “That means that today we could have an equally revolutionary idea right now that the community is ignoring.” | Chemistry and Material Sciences |
Chandrayaan-3 Makes First-Ever Measurements Of Near-Surface Lunar Plasma Environment
The initial assessment of the first-ever measurements of the near-surface lunar plasma environment over the south pole region by RAMBHA-LP payload onboard Chandrayaan-3 lander indicates that plasma there is relatively sparse.
The initial assessment of the first-ever measurements of the near-surface lunar plasma environment over the south pole region by RAMBHA-LP payload onboard Chandrayaan-3 lander indicates that plasma there is relatively sparse, the Indian Space Research Organisation said on Thursday.
Meanwhile, the ILSA payload on Chandrayaan 3 lander to study lunar seismic activity has not only recorded the movements of rover and other payloads, but also has recorded an event, appearing to be a natural one, on August 26.
“The source of this event is under investigation,” ISRO said.
"Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere - Langmuir Probe (RAMBHA-LP) payload onboard Chandrayaan-3 Lander has made first-ever measurements of the near-surface Lunar plasma environment over the south polar region. The initial assessment indicates that the plasma near the lunar surface is relatively sparse,” ISRO said in a social media post.
These quantitative measurements potentially assist in mitigating the noise that Lunar plasma introduces into radio wave communication. Also, they could contribute to the enhanced designs for upcoming lunar visitors, ISRO said.
ISRO also released a video of the Chandrayaan-3 rover rotating in search of a safe route. The rotation was captured by a Lander Imager Camera.
"It feels as though a child is playfully frolicking in the yards of Chandamama, while the mother watches affectionately. Isn't it?," the ISRO social media post read.
Another instrument onboard the rover 'Pragyan' has confirmed the presence of Sulphur (S) in the Lunar region, through a different technique, ISRO said.
The Alpha Particle X-ray Spectroscope (APXS) has detected S, as well as other minor elements.
"This finding by Ch-3 compels scientists to develop fresh explanations for the source of Sulphur (S) in the area: intrinsic?, volcanic?, meteoritic?....?," read the post.
ISRO released a video showing an automated hinge mechanism rotating the 18 cm tall APXS, aligning the detector head to be approximately 5 cm in proximity to the lunar surface.
APXS instrument is best suited for in-situ analysis of the elemental composition of soil and rocks on the surface of planetary bodies having little atmosphere, such as the Moon, an ISRO statement said.
It carries radioactive sources that emit alpha particles and X-rays onto the surface sample. The atoms present in the sample in turn emit characteristic X-ray lines corresponding to the elements present. By measuring the energies and intensities of these characteristic X-rays, researchers can find the elements present and their abundances.
APXS observations have discovered the presence of interesting minor elements, including Sulfur, apart from the major expected elements such as Aluminum, Silicon, Calcium and Iron.
The Laser Induced Breakdown Spectroscope (LIBS) instrument onboard the rover has already confirmed the presence of Sulphur. Detailed scientific analysis of these observations are in progress. | Chemistry and Material Sciences |
It is a remarkable age that we live in — a time when astronomers have the ability to capture direct footage of space explosions that happened long before you and I existed. Such is the case for a cosmic time-lapse video scientists released on Thursday (Sept. 28).
Constructed from about 20 years of Hubble Space Telescope data, the video zooms-in on the bubbling remnants of a supernova, or explosive star death, that happened a staggering 20,000 years or so ago. In particular, the time-lapse focuses on a small sliver of what's known as the Cygnus Loop, a nebula that represents the entirety of one stellar detonation's aftermath.
Nebulas like this one are giant clouds of dust and gas in space, built from the guts of a star that once dramatically died in a supernova eruption. Because they contain all that old star matter, some of these space clouds are known to turn into key components of our universe called "stellar nurseries." As the name suggests, that's where old star parts can come together to form new stars.
Returning to the Cygnus Loop, however, this nebula was first discovered in 1784, but proved to be so spectacular that scientists have continued to gaze into it ever since.
And over time, they've managed to glean some intriguing information from the marvel, such as the fact that it looks kind of like a 120-light-year-wide cotton ball with a bright blobby center and glowing cobweb shell. If you could see the Cygnus Loop from Earth with the unaided eye, according to a Hubble press release on the new time-lapse, it would have a diameter equivalent to six full moons sitting right next to one another.
But, as always, there was more left to learn. And the team's new time-lapse of a Cygnus Loop slice has yielded some striking details.
What does this footage show us?
"Hubble is the only way that we can actually watch what's happening at the edge of the bubble with such clarity," Ravi Sankrit, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland, said in a statement.
For one, as Sankrit explains, the team was able to notice density differences in the shock wave associated with the supernova as it propagates through space. As for what a shock wave is, exactly? Well, basically, when a star explodes, not only does it release an enormous amount of material, but that material is also shot out with an immense amount of force. At risk of simplification, this results in titanic waves of energy that can propagate across breathtaking distances as they heat the area surrounding the exploded star vicinity to breathtaking temperatures — and continuously push the stellar material outward at breathtaking speeds.
And that material also tends to take the shape of threads, or filaments. With regard to the Cygnus Loop's filaments, the team says the section they looked at with the time-lapse data holds what are known as gossamer filaments, which resemble "wrinkles in a bedsheet stretched across two light-years."
"You're seeing ripples in the sheet that is being seen edge-on, so it looks like twisted ribbons of light," William Blair of the Johns Hopkins University, Baltimore, Maryland, said in the statement. "Those wiggles arise as the shock wave encounters more or less dense material in the interstellar medium."
"When we pointed Hubble at the Cygnus Loop we knew that this was the leading edge of a shock front, which we wanted to study," Blair continued. "When we got the initial picture and saw this incredible, delicate ribbon of light, well, that was a bonus. We didn't know it was going to resolve that kind of structure."
But maybe most fascinatingly, it would appear that none of those filaments have slowed down at all or changed shape over the past 20 years thanks to the Loop's shock wave. To put the speed of these waves into perspective, the Loop's wave is forcing filaments to zoom into interstellar space fast enough that we'd travel from Earth to the moon in less than half an hour if we could match the velocity.
Yet, the team says, this is on the slow end. | Chemistry and Material Sciences |
Finding out more about the mysteries of life’s origins on Earth is important, especially as we try to find life beyond our solar system. A new bit of research could change everything, finally bridging how Earth went from being a lifeless marble to the teeming planet that we know today.
See, the journey to figure out how life began on Earth is somewhat experimental, mostly because we just don’t know how it happened. As such, researchers tend to take one of two approaches to it – a top-down view that looks at the origins of life on Earth based on modern animals and plants and a bottom-up approach that starts before life appears on the planet.
Both try to trace the evolutionary lines that have led our planet to become the teeming and ever-changing place that it is today, but neither ever really answered the question of how exactly the first particles of life came into existence. That big mystery of life’s origins could have finally been uncovered.
According to a new paper published in Proceedings of the National Academy of Sciences, the same electron transport chains that power metabolism could be the connective tissue between the bottom-up and top-down approaches that scientists use to research the origins of life on Earth. These chains are the basic points used to transport enzymes, which makes them a perfect bridge in the evolutionary timeline of Earth’s first lifeforms.
“Understanding how these most basic biological systems first took shape will not only give us greater insight into how life works at the most fundamental level, but what life actually is in the first place and how we might look for it beyond Earth,” says Aaron Goldman, an Associate Professor of Biology at Oberlin College, in a statement on the research.
If true, the research gives us additional insight that could help us better understand how life formed on other planets, which NASA can no doubt use as it searches through the bowels of the cosmos for signs of life beyond our own. | Chemistry and Material Sciences |
ESA astronomers will get 8pc of the available observing time on XRISM, a US-Japan mission that European astronomers have contributed hardware and advice to.
The European Space Agency (ESA) has confirmed that the latest x-ray mission it is a part of is ready to launch on 26 August to study some of the most energetic objects in the universe.
The X-Ray Imaging and Spectroscopy Mission, or XRISM, is the result of a collaboration between NASA and Japan’s national space agency, JAXA (Japan Aerospace Exploration Agency), with “significant participation” from the ESA.
X-rays are released during some of the most violent and energetic events in space, including the super-hot gas that envelops galaxy clusters – the building blocks of the universe.
XRISM has been designed to detect x-ray light from this gas to help astronomers measure the total mass of these systems, revealing data about the formation and evolution of the universe.
“X-ray astronomy enables us to study the most energetic phenomena in the universe,” explains Matteo Guainazzi, an ESA project scientist for XRISM.
“It holds the key to answering important questions in modern astrophysics: how the largest structures in the universe evolve, how the matter we are ultimately composed of was distributed through the cosmos and how galaxies are shaped by massive black holes at their centres.”
Guainazzi said XRISM will be a “valuable bridge” between the ESA’s other x-ray missions, such as XMM-Newton, which has been in space for 24 years, and Athena, due to launch in the late 2030s.
The ESA said XRISM’s observations of galaxy clusters will also provide insight into how the universe produced and distributed the chemical elements, because the hot gas within clusters is a remnant of the birth and death of stars over the history of the universe.
By studying x-rays emitted by this gas, XRISM will aim to discover which ‘metals’ – elements heavier than hydrogen and helium – it contains and map how the universe became enriched with them.
In return for providing hardware and scientific advice, the ESA will be allocated 8pc of XRISM’s available observing time. This will enable European scientists to propose celestial sources to observe in x-ray light and hopefully make breakthroughs in astronomy.
“ESA and the European community have a history of involvement in JAXA’s high-energy space telescopes,” explains Matteo. “Continuing this partnership through XRISM comes with enormous benefits to both space agencies.”
XRISM is scheduled to launch on a H-IIA rocket from the Tanegashima Space Center in Japan on 26 August. It will be livestreamed on JAXA’s YouTube channel.
10 things you need to know direct to your inbox every weekday. Sign up for the Daily Brief, Silicon Republic’s digest of essential sci-tech news. | Chemistry and Material Sciences |
While the James Webb Space Telescope observed the atmosphere of an alien world 120 light-years away, it picked up hints of a substance only made by living things — at least, that is, on Earth.
This molecule, known as dimethyl sulfide, is primarily produced by phytoplankton, microscopic plant-like organisms in salty seas as well as freshwater.
The detection by Webb, a powerful infrared telescope in space run by NASA and the European and Canadian space agencies, is part of a new investigation into K2-18 b, an exoplanet almost nine times Earth's mass in the constellation Leo. The study also found an abundance of carbon-bearing molecules, such as methane and carbon dioxide. This discovery bolsters previous work suggesting the distant world has a hydrogen-rich atmosphere hanging over an ocean.
Such planets believed to exist in the universe are called Hycean, combining the words "hydrogen" and "ocean."
"This (dimethyl sulfide) molecule is unique to life on Earth: There is no other way this molecule is produced on Earth," said astronomer Nikku Madhusudhan in a University of Cambridge video. "So it has been predicted to be a very good biosignature in exoplanets and habitable exoplanets, including Hycean worlds."
But hold your horses.
Scientists involved in the research caution that the evidence supporting the presence of dimethyl sulfide — DMS, for short — is tenuous and "requires further validation," according to a Space Telescope Science Institute statement. Follow-up Webb observations should be able to confirm it, said Madhusudhan, the lead author on the research, which will be published in The Astrophysical Journal Letters.
Researchers use Webb to conduct atmospheric studies of exoplanets. Discoveries of water and methane, for example — important ingredients for life as we know it — could be signs of potential habitability or biological activity.
"This molecule is unique to life on Earth: There is no other way this molecule is produced on Earth."
The method this team employed is called transmission spectroscopy. When planets cross in front of their host star, starlight is filtered through their atmospheres. Molecules within the atmosphere absorb certain light wavelengths, or colors, so by splitting the star’s light into its basic parts — a rainbow — astronomers can detect which light segments are missing to discern the molecular makeup of an atmosphere.
Madhusudhan said this study marks the first time exoplanet hunters have ever found methane and hydrocarbons. That, coupled with the absence of molecules like ammonia and carbon monoxide, is an intriguing cocktail for an atmosphere.
"Of all the possible ways to explain it, the most plausible way is that there is an ocean underneath," he said.
K2-18 b orbits a cool dwarf star in its so-called "habitable zone," the region around a host star where it's not too hot or cold for liquid water to exist on the surface of a planet. In our solar system, that sweet spot encompasses Venus, Earth, and Mars.
Although K2-18 b lies in the Goldilocks space, that fact alone doesn't mean the planet can support life. The researchers don't know what the temperature of the water would be, so whether it's habitable remains a mystery.
"But it's got all the indications of being so," said Madhusudhan. "We need more observations to establish that more firmly." | Chemistry and Material Sciences |
Diamonds contain evidence of the mantle rocks that helped buoy and grow the ancient supercontinent Gondwana from below, according to new research from a team of scientists led by Suzette Timmerman -- formerly of the University of Alberta and now at the University of Bern -- and including Carnegie's Steven Shirey, Michael Walter, and Andrew Steele. Their findings, published in Nature, demonstrate that superdeep diamonds can provide a window through space and time into the supercontinent growth and formation process.
For billions of years, Earth's landmasses have been ripped apart and smashed back together by plate tectonics, periodically forming giant supercontinents. This formation process results from large-scale convection of the planet's mantle. But the records of these events are poorly preserved, because the oceanic crust is young and continually sinks beneath the planet's surface by a process called subduction, while the continental crust only provides a limited view of Earth's deep workings.
Surprisingly, the research team was able to show that superdeep diamonds that formed between 300 and 700 kilometers below Earth's surface can reveal how material was added to the base of a once-mighty supercontinent.
"These diamonds allow us to see how deep plate tectonic processes relate to the supercontinent cycle," Shirey said.
The supercontinent Gondwana is thought to have formed between 800 and 550 million years ago in Neoproterozoic times. Starting over the present-day location of the South Pole, it incorporated the landmasses that make up present day South America, Africa, the Middle East, India, and Australia.
"By revealing the geological processes that contributed to Gondwana's growth, scientists can better understand the forces that shaped Earth's history and phenomenon of continental stability, which is -- of course -- fundamental to the eventual success of life on our planet," added Walter.
About 40 to 250 kilometers beneath the surface, geologic formations called mantle keels act as the foundation of the continental crust. The material that forms these keels thickened, stabilized, and cooled under the continental blocks to form strong, buoyant structures that can resist the relentless destructive forces of Earth's tectonic activity.
Remnants of the mantle rocks that helped form the keel can be found in tiny silicate and sulfide inclusions hidden inside these superdeep diamonds. Typically flaws in normal gem diamonds, these inclusions are the best friends of a geoscientist. They were identified, isolated, studied crystallographically, and then radiometrically dated to determine their geologic ages.
This work was carried out by researchers at the University of Alberta and the Carnegie Institution for Science, as well as by other teams of diamond specialists at the Vrije Universiteit Amsterdam, University of Bristol, and the University of Padua. It required many steps, including shipping the diamonds around the world several times, and deployed some of the most precise mass spectrometers and X-ray diffractometers available.
"The study of such rare samples with a variety of measurement techniques required major teamwork. But even more remarkable is how careful analyses of such minute amounts of material can shed light on the evolution of Earth's largest continental landmasses," Timmerman explained.
"The age of these inclusions provides a record of when buoyant mantle was added to Gondwana from below, thereby scaffolding, underpinning, and growing the supercontinent" added Shirey.
Then, about 120 million years ago, the supercontinent once buoyed by the rocks that housed these diamonds started to break up and, eventually, 30 million years later -- around 90 million years ago -- the diamonds -- and the inclusions trapped inside them -- were brought to the Earth's surface in violent volcanic eruptions of diamond-bearing kimberlite magma.
Now, by combining their lab analysis with existing models of tectonic movement and continent migration, the researchers can use these remarkably well-traveled diamonds to understand how material welds continental fragments together from below, stabilizing such a super-sized continental landmass.
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Scientists find 'missing ingredient' for pink diamonds
Scientists said on Tuesday they have found the "missing ingredient" for pink diamonds, some of the world's most expensive stones due their rarity and beauty, and the discovery could help find more.
More than 90 percent of all the pink diamonds ever found were discovered at the recently closed Argyle mine in the remote northwest of Australia.
But exactly why Argyle—which unlike most other diamond mines does not sit in the middle of a continent but on the edge of one—produced so many pink gems has remained a mystery.
In a new study published in the journal Nature Communications, a team of Australia-based researchers said the pink diamonds were brought to the Earth's surface by the break up of the first supercontinent around 1.3 billion years ago.
Hugo Olierook, a researcher at Curtin University in the state of Western Australia and the study's lead author, told AFP that two of the three ingredients for forming pink diamonds had already been known.
The first ingredient is carbon—and it must be in the bowels of Earth.
Anything shallower than 150 kilometers (93 miles) deep would be graphite—"that stuff in your pencils, not nearly as pretty on an engagement ring", Olierook said.
The second ingredient is just the right amount of pressure, to damage the otherwise clear diamonds.
"Push just a little bit and it turns pink. Push a little too hard and they turn brown," he said.
Most of the diamonds discovered at Argyle were of this less valuable brown hue, he added.
'Like a champagne cork'
The missing ingredient was the volcanic event that sent the diamonds shooting up to the Earth's surface, where humans could get their hands on them.
In the 1980s it was estimated that the Argyle diamonds emerged 1.2 billion years ago.
But there was no "trigger" for the rare diamonds to rise at that time, Olierook said, so the researchers sought to establish a more accurate timeline.
They used a laser thinner than a human hair to probe tiny crystals in an Argyle rock sample supplied by the mine's owner, Anglo-Australian mining giant Rio Tinto.
By measuring the age of elements in the crystals, the researchers determined that Argyle was 1.3 billion years old—meaning the diamonds came up 100 million years later than previously thought.
That lines up with the break-up of the world's first supercontinent, known as Nuna or Columbia.
In Nuna, "just about every single landmass on Earth was squashed together", Olierook said.
The immense pressure that twisted color into the diamonds—the second ingredient—occurred during collisions between western Australia and northern Australia 1.8 billion years ago.
When Nuna started to break up five hundred million years later, it re-aggravated the "scar" from that event, Olierook said.
Magma shot up through this old scar "like a champagne cork going off", taking the diamonds along for the ride, he added.
Study co-author Luc Doucet said such a "massive explosion"—which sent the diamonds traveling at near the speed of sound—has not taken place in recorded human history.
Where to look next?
Over the last 200 years, people have mostly looked for diamonds in the center of massive continents.
But knowing the "missing ingredient" for pink diamonds could assist future efforts to find the rare stones, Olierook said, adding that discovering more was unlikely to be easy or quick.
Old mountain belts marking Nuna's breakup near the edges of continents have the potential to be home to a new "pink diamond paradise", he said, naming Canada, Russia, southern Africa and Australia as possible locations.
John Foden, an expert on diamonds at the University of Adelaide not involved in the study, told AFP that the researchers had "convincingly shown" the age of the Argyle diamonds.
But he cautioned that other diamond-rich provinces had also been linked to Nuna's break-up—and they had not produced pink diamonds.
This suggests that "pinkness seems to be a local Argyle attribute", he added.
The Argyle mine closed in 2020 due to "various financial reasons", Olierook said, meaning the value of pink diamonds could continue to rise as supply stalls.
More information: Hugo Olierook, Emplacement of the Argyle diamond deposit into an ancient rift zone triggered by supercontinent breakup, Nature Communications (2023). DOI: 10.1038/s41467-023-40904-8. www.nature.com/articles/s41467-023-40904-8
Journal information: Nature Communications
© 2023 AFP | Chemistry and Material Sciences |
The James Webb Space Telescope (JWST) has discovered that galaxies in the early universe were cosmic rule-breakers. This discovery sheds light on how early galaxies evolved and the fundamental processes that shaped the universe as we see it today.
To discover the truth about these cosmic scofflaws, a team of astronomers used the JWST to gaze over 12 billion years back in time and observe galaxies as well as the rules they followed through cosmic history. The crew found that the same set of rules continuously prevailed, connecting the rate of star birth to galactic masses to chemical compositions. But these rules traced only so far back. The earliest galaxies defied them.
It was like the galaxies had a rulebook that they followed — but astonishingly, this cosmic rulebook appears to have undergone a dramatic rewrite during the universe’s infancy," Claudia Lagos, an associate professor at the University of Western Australia, said in a statement. "The most surprising discovery was that ancient galaxies produced far fewer heavy elements than we would have predicted based on what we know from galaxies that formed later."
This disparity hadn’t been spotted before because instruments used prior to the JWST hadn’t been powerful enough to see the chemical makeup of galaxies as far back as around 11 billion years ago. The JWST, however, allowed this team to look back to just a few hundred million years after the Big Bang, which showed a break in the relationship between star formation, mass and chemistry.
When did things get heavy for the cosmos?
When the universe first began to form the first stars and galaxies, it was filled with hydrogen and helium — the two lightest elements — with the former being the most dominant by far.
Only a smattering of heavier elements-which astronomers call “metals” existed until the first generation of stars forged them at their hearts and then dispersed them through the universe at the end of their lives via massive supernova explosions.
This material was eventually incorporated into the next generation of stars, meaning these stars, and thus the galaxies they sit in, had a higher concentration of metals — a measure called "metallicity." That process of metal enrichment has continued throughout the entire 13.8 billion years of cosmic history, meaning early galaxies are indeed expected to have lower metallicities than their modern counterparts.
But even factoring this in, the team found that the metallicity of early galaxies was still lower than expected. Much lower.
"Their chemical abundance was approximately four times lower than anticipated, based on the fundamental-metallicity relation observed in later galaxies," Lagos continued, explaining that the early galaxies observed by the team delivered even more surprises.
The team suggests the disparity may exist because galaxies just a few hundred million years after the Big Bang could still be intimately connected with the intergalactic medium — the wispy hot gas and dust that exists between galaxies.
"The early galaxies continually received new, pristine gas from their surroundings, with the gas influx diluting the heavy elements inside the galaxies, making them less concentrated," Lagos concluded.
As such, the team’s findings could challenge current models of galactic evolution and the mechanism that facilitated the development of the first galaxies.
The research was published on Sept. 21 in the journal Nature. | Chemistry and Material Sciences |
Earth may owe its supply of pink diamonds to the breakup of the planet's first supercontinent.
The Argyle formation in western Australia is the source of 90% of pink diamonds on Earth. It's an odd spot for diamonds: at the edge of a continent rather than in the center, where most diamond mines tend to be, and in a type of rock that is slightly different from the rock that usually bears diamonds.
Now, new research suggests that the strange color and strange geology likely come from a similar origin, the plate tectonics of the planet some 1.3 billion years ago. Recent studies from other researchers suggest that these large-scale continental movements are important for bringing diamonds of other colors to the surface, as well.
"The breakup of these continents are fundamental at getting these diamonds up from these deep depths," said Hugo Olierook, a research fellow at Curtin University in Australia and lead author of the new study on the origin of the pink diamonds, published today (Sept. 19) in the journal Nature.
Pink diamonds are different from blue or yellow diamonds, which get their color from impurities like nitrogen and boron. In contrast, pink diamonds are colorful only because their crystalline structure has been bent. The Argyle also hosts a lot of brown diamonds, which get their color from an even greater deformation of the crystal structure.
"Pinks are, say, a small push, if you like," Olierook told Live Science."You push a little bit too hard and they turn brown."
The Argyle diamond mine closed in 2020. Research from the 1980s, shortly after the discovery of the cache, had pegged the age of the rocks there at about 1.2 billion years. But even the scientists who did that original work were not convinced of that number, Olierook said, due to technical limitations. He and his colleagues decided to check again using modern equipment, particularly laser ablation technology that allowed them to carefully pinpoint the individual crystals in the rock they were dating.
These new results revealed that the pink-diamond-bearing Argyle is 100 million years older than previously believed, at 1.3 billion years in age. That puts its origin right at the beginning of the breakup of the supercontinent Nuna.
This paints a new picture of how the Argyle's pink diamonds came to be, Olierook said. First, some time around 1.8 billion years ago, two bits of continental crust smashed together as part of the formation of Nuna. What would eventually become the Argyle formation sat right at this juncture. The collision of the crust is probably what bent the diamonds and made them pink, Olierook said.
It was the breakup of Nuna, 500 million years later, that then brought the diamonds to the surface. The continent did not split right at the Argyle, but the stretching that went on likely weakened the "old wound" of the continental collision where the formation sits. This weakening allowed an eruption of deep rock — carrying those rare pink diamonds — that occurred over days to weeks.
"I think we’re seeing how in general, the mantle is destabilized when supercontinents break up," Olierook said. "That rifting process seems to not just work the edges, but also seems to work in the middle of continents, and that's perhaps what is allowing diamonds to come up in the middle of them" in most cases, he said.
Tracking diamonds' paths from the depths to the surface is helpful for understanding how carbon moves in and out of the planet's interior, Olierook said. (Diamonds are mostly pure carbon.) The Argyle is a pretty unique spot, he said, but there is a chance that pink diamonds could be found elsewhere on Earth.The problem is that if pink diamonds form on the edges of continents, they're likely to be buried under a lot of eroded-away rock and sediment, he said.
"I do think we will find another Argyle, another pink diamond treasure trove," he said, "but it’s going to take a lot of luck."
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Stephanie Pappas is a contributing writer for Live Science, covering topics ranging from geoscience to archaeology to the human brain and behavior. She was previously a senior writer for Live Science but is now a freelancer based in Denver, Colorado, and regularly contributes to Scientific American and The Monitor, the monthly magazine of the American Psychological Association. Stephanie received a bachelor's degree in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz. | Chemistry and Material Sciences |
Nasa’s Psyche spacecraft rocketed away Friday on a six-year journey to a rare metal-covered asteroid.
Most asteroids tend to be rocky or icy, and this is the first exploration of a metal world. Scientists believe it may be the battered remains of an early planet’s core, and could shed light on the inaccessible centers of Earth and other rocky planets.
SpaceX launched the spacecraft into a midmorning sky from Nasa’s Kennedy Space Center in Florida. Named for the asteroid it’s chasing, Psyche should reach the huge, potato-shaped object in 2029.
After decades of visiting faraway worlds of rock, ice and gas, Nasa is psyched to pursue one coated in metal. Of the nine or so metal-rich asteroids discovered so far, Psyche is the biggest, orbiting the sun in the outer portion of the main asteroid belt between Mars and Jupiter alongside millions of other space rocks. It was discovered in 1852 and named after Greek mythology’s captivating goddess of the soul.
“It’s long been humans’ dream to go to the metal core of our Earth. I mean, ask Jules Verne,” said lead scientist Lindy Elkins-Tanton of Arizona State University.
“There’s one way in our solar system that we can look at a metal core and that is by going to this asteroid.”
Astronomers know from radar and other observations that the asteroid is big — about 144 miles (232km) across at its widest and 173 miles (280km) long. They believe it’s brimming with iron, nickel and other metals, and quite possibly silicates, with a dull, predominantly gray surface likely covered with fine metal grains from cosmic impacts.
Scientists envision spiky metal craters, huge metal cliffs and metal-encrusted eroded lava flows greenish-yellow from sulfur.
“There’s a very good chance that it’s going to be outside of our imaginings, and that is my fondest hope,” she said.
Believed to be a planetary building block from the solar system’s formation 4.5 billion years ago, the asteroid can help answer such fundamental questions as how did life arise on Earth and what makes our planet habitable, according to Elkins-Tanton.
On Earth, the planet’s iron core is responsible for the magnetic field that shields our atmosphere and enables life.
Led by Arizona State University on Nasa’s behalf, the $1.2bn mission will use a roundabout route to get to the asteroid. The van-size spacecraft with solar panels big enough to fill a tennis court will swoop past Mars for a gravity boost in 2026. Three years later, it will reach the asteroid and attempt to go into orbit around it, circling as high as 440 miles and as close as 47 miles until at least 2031. | Chemistry and Material Sciences |
"The cosmos is within us. We are made of star stuff. We are a way for the universe to know itself." Carl Sagan
During the course of his 1980s mini-series "Cosmos," astronomer and science communicator Carl Sagan said many inspirational and profound things based on our understanding of the universe. But arguably, none have resonated with the general public more than the statement above.
With this sentiment, Sagan, who passed away in 1996 at the age of 62, was talking about the cosmic origins of humanity.
And in a new video from the European Southern Observatory (ESO), part of the Chasing Starlight series, astrophysicist Suzanna Randall explains what this statement means and how it relates to the elements that comprise our bodies.
How the universe became more metal
Randall explains that shortly after the Big Bang, the dense and hot universe was comprised mainly of the two lightest elements, hydrogen and helium, as well as a smattering of heavier elements collectively known as metals.
"But, you can't make up something as complex as the human body of just helium and hydrogen," she explains. "So, where do the other more complex elements that make up our body and the rest of the universe come from?"
Winding the cosmic clock forward to around 100 million years post-Big Bang, Randall explained that this is when the first nebulas — vast clouds of hydrogen and helium — had formed in the universe. When overly dense regions of these nebulas gathered more and more mass from their surroundings, they eventually collapsed under their own gravity, birthing the first generation of stars.
But, like the universe at that time, these stars were all hydrogen and helium with a negligible amount of metals.
This first generation of stars fused hydrogen in their cores to create helium, something that Randall points out the sun, our 4.6 billion-year-old star, is doing today.
Why did stars have to die for you to live?
This all means that, at the time when the first stars existed, the universe still didn't have enough heavy elements needed to form our bodies like nitrogen, oxygen and carbon.
But this changed as the first generation of stars began to die.
"When the hydrogen in the core of the star has been used up, things start happening very quickly," Randall says. "The star enters a new phase of its life, called the red giant phase."
During the red giant phase, the cores of these first stars would have contracted. Meanwhile, their outer layers, where the nuclear fusion of hydrogen to helium was still taking place, would have puffed out and increased the stars' sizes by as much as 100 times. The core would've continued to contract until conditions at the hearts of the stars, which would've been much more massive than the sun, became hot and dense enough to start fusing helium into heavier elements. And there, elements like carbon and oxygen, which comprise around 84% of our bodies, spawned into existence.
"The majority of the atoms in my body are actually created deep inside stars in these incredibly hot stellar furnaces," Randall explained.
The universe finally got the "stuff" needed for life, but that stuff wasn't of much use locked in the hearts of red giant stars. Don't worry, though, these elements wouldn't stay confined for long — not in cosmic terms, anyway.
"Stars with more than about eight solar masses continue to fuse elements in their core, and they create heavier and heavier elements — as heavy as iron," Randall said. "At some point, they have to die, and they go out with a bang. They explode as supernovae."
During those cosmic explosions, Randall says some astronomers believe even heavier elements, like gold or platinum, had formed. However, other scientists think it would've had to take the collision of two stellar corpses, called neutron stars, and therefore a kilonova explosion to create such precious elements.
What is certain about the supernova explosions of the universe's first stars is they took all the elements forged by these stars during their lives and flung them out into the cosmos.
Eventually, these elements were integrated into nebulas and thus became part of the next generation of stars born from those vast dust clouds.
That means this next generation of stars was more "metal-rich" than the preceding generation. This continued through to the creation of the third generation of stars, one of which is the sun.
Enriched material from the nebula that created the sun, but didn't manage to become part of our star 4.6 billion years ago, then formed a disk of material around the stellar body called a protoplanetary disk.
"As it turns out, Carl Sagan was right. We are literally made up of star stuff," Randall said. "And the story of stars in their lives is also the story of the elements that make up our body. We're all part of this grand cosmic cycle."
As the astrophysicist points out, however, we maybe shouldn't let this go to our heads too much. As an ego-cleanser, Randall concludes by adding: "Before you get too excited, cockroaches are also made up of star stuff." | Chemistry and Material Sciences |
Scientists may have made a major breakthrough in the quest to produce limitless energy. According to a new study published in the journal American Chemical Society, scientists are looking deeper at a molecule known as azulene, which is a blue-light emitting molecule that seems to flout the fundamental rules of photochemistry.
The hope is that understanding how azulene and other molecules like it convert energy through fluorescence will allow us to build our own molecules to more efficiently convert photons from the Sun into usable electricity, thus creating cleaner energy.
The idea is all part of the normal progression to try to make solar cells more efficient. Looking back at the history of these electricity-generating cells, the first solar cell in 1883 could convert less than one percent of the Sun’s photons to usable electricity. That was just the first baby step towards creating limitless energy, though.
Now, solar cells have seen some significant upgrades and changes. While we aren’t to the point of being able to generate limitless energy just yet, we do have solar cells that can turn close to 50 percent of the Sun’s photons into electricity, and even solar panels that generate electricity in the dark.
Some researchers hope that understanding the mystery of how a molecule like azulene runs counter to a photochemical idea we know as Kasha’s rule. This rule essentially helps explain how molecules emit light when in various states. Unlike other molecules, though, azulene doesn’t seem to follow Kasha’s rule.
“It’s based on the aromaticity and the antiaromaticity of that molecule in different excited states,” lead author of the study, Tomáš Slanina, shared in a press statement. “We can think of aromaticity as a kind of internal stabilization of that molecule. When that molecule is aromatic, it’s happy, it’s stable. When it’s antiaromatic, it’s trying its best to escape that state somehow.”
For azulene, though, it is stable in its ground state, but unstable (antiaromatic) in its first excited state. It’s an interesting discovery that could help lead scientists to a breakthrough in the search for limitless energy. However, what that limitless energy would look like exactly is still unclear. For now, at least we have a thread to pull on. | Chemistry and Material Sciences |
Mars: new evidence of an environment conducive to the emergence of life
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Using data from NASA's Curiosity rover, scientists at the CNRS, Université Toulouse III – Paul Sabatier and Université Claude Bernard Lyon 1, with the participation of CNES, have discovered patterns on Mars that provide evidence of a cyclical climate similar to that of Earth's. This major discovery opens up new prospects for research into the origin of life. The results of the study are published on 9 August 2023 in the journal Nature.
The surface of Mars, unlike the Earth's, is not constantly renewed by plate tectonics. This has resulted in the preservation of huge areas of terrain remarkable for their abundance in fossil rivers and lakes dating back billions of years. Since 2012, NASA's Curiosity, the first rover to ever explore such ancient remains, had already detected the presence of simple organic molecules which can be formed by geological as well as biological processes.
However, the emergence of primitive life forms, as hypothesised by scientists, initially requires environmental conditions favourable to the spontaneous organisation of these molecules into complex organic compounds. Such conditions are precisely what have recently been discovered by a research team from the Institut de Recherche en Astrophysique et Planétologie (CNRS/Université de Toulouse III - Paul Sabatier/CNES) and the Laboratoire de Géologie: Terre, Planètes, Environnement (CNRS/ENS de Lyon/Université Claude Bernard Lyon 1), together with their US and Canadian colleagues.
Using the Mastcam1 and the ChemCam2 instruments on Curiosity, they have discovered deposits of salts forming a hexagonal pattern in sedimentary layers dating from 3.8 to 3.6 billion years ago. Similar to the hexagons observed in terrestrial basins that dry out seasonally, they are the first fossil evidence of a sustained, cyclical, regular Martian climate with dry and wet seasons. By letting molecules repeatedly interact at different concentrations, independent laboratory experiments have shown that this kind of environment provides the ideal conditions for the formation of complex precursor and constituent compounds of life, such as RNA.
These new observations should enable scientists to take a fresh look at the large-scale images obtained from orbit, which have already identified numerous terrains with a similar composition. They now know where to look for traces of the natural processes that gave rise to life, of which no vestiges remain on Earth.
- 1https://mars.nasa.gov/msl/spacecraft/instruments/mastcam/
- 2ChemCam was built by a French-US consortium under the responsibility of the Institut de Recherche en Astrophysique et Planétologie (CNRS/Université de Toulouse III - Paul Sabatier/CNES) and the Los Alamos National Lab (United States). In France, the design of the instrument was funded by the French space agency CNES, the CNRS, the French Alternative Energies and Atomic Energy Commission CEA, and a number of universities. Mars Science Laboratory is a NASA mission run by the Jet Propulsion Laboratory (USA), which designed and operates the Curiosity rover.
Sustained wet-dry cycling on early Mars. W. Rapin, G. Dromart, B.C. Clark, J. Schieber, E.S. Kite, L.C. Kah, L.M. Thompson, O.Gasnault, J. Lasue, P-Y. Meslin, P.J. Gasda, N.L. Lanza. Nature, 9 August 2023.
DOI : https://doi.org/10.1038/s41586-023-06220-3 | Chemistry and Material Sciences |
NASA has launched a mission to a rare asteroid covered in metal that is two billion miles (3.6bn km) and six years' travel time away from Earth.
Scientists hope exploring the Psyche asteroid will help them understand more about how Earth formed and what makes it habitable.
Lead scientist Lindy Elkins-Tanton, of Arizona State University, said: "It's long been humans' dream to go to the metal core of our Earth. I mean, ask [author] Jules Verne.
"The pressure is too high. The temperature is too high. The technology is impossible. But there's one way in our solar system that we can look at a metal core and that is by going to this asteroid."
Most asteroids tend to be rocky or icy, and this is the first look at a metal one - the team is also hoping to take the first-ever images of it.
Psyche, which may be the battered remains of a planetesimal, or a building block of a rocky planet, is the largest of the nine metal-rich asteroids discovered so far, NASA said.
The potato-shaped rock measures about 144 miles by 173 miles (232km by 280 km) at its widest and has a mass of about 440 billion pounds.
It will dwarf the van-sized spacecraft, with solar panels big enough to fill a tennis court.
Also called Psyche, the spacecraft was launched on a SpaceX Falcon Heavy rocket from NASA's Kennedy Space Centre, in Florida, on Friday.
The agency believes the asteroid, which orbits the sun between Mars and Jupiter, is brimming with iron, nickel and other metals - and quite possibly silicates. It is a dull grey colour, probably because its surface is covered with fine metal grains from cosmic impacts.
It was discovered in 1852 and named after Greek mythology's captivating goddess of the soul.
As to what they will find, scientists imagine spiky craters, huge metal cliffs and metal-encrusted eroded lava flows that are greenish-yellow from sulfur. However, Ms Elkins-Tanton admitted that is "almost certain to be completely wrong".
Tiny amounts of gold, silver, platinum or iridium - iron-loving elements - could be dissolved in the asteroid's iron and nickel, she said.
"There's a very good chance that it's going to be outside of our imaginings, and that is my fondest hope."
Believed to be a planetary building block from the solar system's formation 4.5 billion years ago, the asteroid can help answer fundamental questions such as how life began on Earth and what makes our planet habitable, according to Ms Elkins-Tanton.
Read more:
NASA's 'incredible' findings from asteroid
What is asteroid Psyche and what can it tell us?
Led by Arizona State University on NASA's behalf, the $1.2 billion (£985m) mission will swoop past Mars for a gravity boost in 2026.
Three years later, it will reach the asteroid and attempt to go into orbit around it, circling it at a distance of between 47 and 440 miles (75 and 700 km) until at least 2031. | Chemistry and Material Sciences |
Saturday Citations: Muons and the standard model, refuting an apocalypse, stellar tidal waves
This week on phys.org, we published news about muons, gigantic stellar waves, a Homo-erectus-thwarting mini ice age, and a new whale guy.
Particle wobbles: Macro-scale physicists have achieved nanoscale precision measurements of the muon anomalous magnetic moment as part of a decades-long agenda of shaking the standard model and shouting "Are you complete yet?" The unforthcoming standard model has stubbornly refused to explain subatomic phenomena like dark matter, and scientists have been searching at increasingly smaller scales for particles within the standard model that could account for them. One such mystery: If you run muons in circles around a powerful magnet, they wobble, decaying in unexpected directions. This is the anomalous magnetic moment. It's possible that undiscovered particles nudge muons under these conditions. Does this latest project, the Muon g-2 experiment, resolve the question? Haha, no. But it does confirm earlier findings at a much higher level of precision, which is a pretty big deal, at least according to physicists, to whom "big" is, like, the size of an electron.
New whale guy: If you relate emotionally to organisms that crawled from the ocean to the land, said "lol, no," and waddled back into the sea forever, a new whale guy just dropped. An international team of scientists discovered an extinct whale that inhabited the Tethys Ocean, an ancient sea that once covered modern Egypt. They've named it after notable 18th-dynasty pharaoh Tutankhamen. Tutcetus ratanesis is a basilosaurid, an extinct family that lived during the middle to early late Eocene. Tutcetus is the smallest species of basilosaurid ever discovered, expanding the size range of the family and illuminating early whale evolution.
Apocalypse Not: In 2022, researchers led by Dr. Kenneth Tankersley published a sensational paper in Scientific Reports claiming that the Indigenous Hopewell culture, which thrived around what is now Cincinnati, was destroyed by an exploding comet 1,500 years ago. OK! One and a half years later, archaeologists at Ball State University say that not only is the word "destroyed" doing some heavy lifting, the words "by," "an," "exploding" and "comet" are similarly load-bearing structural elements. In their response paper, also published in Scientific Reports, researchers including Dr. Kevin C. Nolan basically challenge all of the individual words in the original paper.
"There is no evidence for catastrophically burned habitations at any of the 11 Hopewell sites studied by Tankersley's team," Dr. Nolan said. "The burned surfaces identified by the University of Cincinnati researchers are either localized episodes of burning for ceremonial purposes, such as cremating the honored dead, or are not even burned surfaces at all." Fair enough! The response paper also carefully details "numerous instances of possibly intentional data manipulations."
Earth inhospitable: In the midst of a planetary heatwave, it's easy to think, "a massive North Atlantic cooling event would be pretty good right now." Contrariwise, Archaic Homo erectus individuals living in western Europe about 1.5 million years ago may very well have said, "Bro, you do not want to live through an ice age." Citation: a study published in Science by an international group of scientists reporting that a massive North Atlantic cooling event shifted the climate just as good old Homo erectus was starting to get a foothold in the hemisphere. "This massive cooling marks one of the first terminal stadial events in the paleoclimatic record. It occurred during the last phase of a glacial cycle, when ice sheets disintegrated, releasing large amounts of freshwater into the ocean, and causing ocean circulation changes and a southward expansion of sea ice," says Prof. Chronis Tzedakis from University College London (UCL), senior author of the study.
The researchers built a global climate simulation correlating ocean sediment core data and computer simulations of glacial freshwater flows. They used the model as input for a human habitation model, finding that early human species would have been unable to survive. Indeed, the paleontological record indicates the absence of stone tools and human remains in western Europe over the next 200,000 years. The researchers also point out that this cooling period was "brief," meaning only 4,000 years long, 3,999 years and nine months longer than I'm willing to tolerate the average cold winter. Bro, I do not want to live through an ice age.
Stars: immense. You: insignificant: Researchers at the Harvard-Smithsonian Center for Astrophysics have determined the cause of the extreme swings of brightness in a heartbeat binary called MACHO 80.7443.1718: titanic waves of plasma as tall as three suns crashing on one side.
Heartbeat stars are close pairs of stars with brightness that periodically pulses like the rhythm of a heart. When they approach closely in their oval orbits, their mutual gravity generates tides, stretching and distorting their masses and changing the amount of light visible from Earth. The larger of the two MACHO 80.7443.1718 stars, which is 35 times larger than the sun, exhibits regular brightness swings of 20%, higher than any other known heartbeat star. "Each crash of the star's towering tidal waves releases enough energy to disintegrate our entire planet several hundred times over," says postdoctoral researcher Morgan MacLeod, as though none of us have ever seen the Pale Blue Dot photo and needed further confirmation of the Earth's relative insignificance and vulnerability in an infinite universe of vast energies and immense forces. Have a great weekend!
© 2023 Science X Network | Chemistry and Material Sciences |
The Webb Space Telescope has made its latest significant discovery: the observation of carbon dioxide coming from a part of Europa, the frozen moon orbiting Jupiter which harbors a salty water ocean under its icy surface.
The finding is a boost for astrobiology, or the search for life beyond Earth. Carbon is critical for life as we know it—life on Earth is carbon-based—so the element appearing in Europa’s oceans, long thought a potential venue for alien life, boosts those hopes. Water is also necessary for life on Earth, hence the particular excitement around Europa over, say, Mars, which has an abundance of carbon dioxide but has no liquid water, at least none we yet know of.
The search for alien life is also the cornerstone of the Perseverance rover’s mission on Mars, and a foundational aspect of other space agency projects, including NASA’s next-generation Habitable Worlds Observatory. But Europa, always a target of astrobiologists, has now gotten a big boost from the carbon dioxide detection.
Webb’s Near-Infrared Spectrograph (NIRSpec) instrument detected carbon dioxide on Europa’s “chaos region” of Tara Regio. In this area, the surface ice has been disrupted, allowing substances in the moon’s ocean to rise to the surface.
Analysis of the Webb data was published today in two independent Science papers; one of the papers explored the potential composition of Europa’s subsurface ocean based on the specific area of the carbon dioxide detection, and the other paper identified the carbon source and found no plumes from the moon, a further indication that the Europa’s surface disruption allowed the carbon dioxide to appear.
“We now think that we have observational evidence that the carbon we see on Europa’s surface came from the ocean. That’s not a trivial thing. Carbon is a biologically essential element,” said Samantha Trumbo, a planetary scientist at Cornell University and lead author of one of the study’s analyzing the new data, in a European Space Agency release.
Like Saturn’s icy moon Enceladus, Europa occasionally issues gigantic plumes of water vapor that scientists thought may have carried the carbon to the surface of Tara Regio. In May, Webb used NIRSpec to identify a water plume more than 20 times the size of Enceladus itself extending from the moon’s south pole.
But the Webb data didn’t indicate a plume was at play in the 1,944-mile-wide (3,128-kilometer-wide) field of view of Europa studied by NIRSpec—which doesn’t outright certify there wasn’t a plume, but it didn’t show up in the data if so.
“Previous observations from the Hubble Space Telescope show evidence for ocean-derived salt in Tara Regio,” Trumbo said. “Now we’re seeing that carbon dioxide is heavily concentrated there as well. We think this implies that the carbon probably has its ultimate origin in the internal ocean.”
More insights into Europa are on the horizon. ESA’s JUpiter ICy moons Explorer, or JUICE, launched from French Guiana in April, with an anticipated arrival in Jupiter’s system in 2031. JUICE will obviously study Europa, but also the moons Ganymede and Callisto, which have their own oceans. Not to be outdone, NASA’s Europa Clipper mission is set to launch in October 2024 and arrive at Europa specifically in 2030, and will get closer to the moon’s surface than any spacecraft before it.
“Understanding the chemistry of Europa’s ocean will help us determine whether it’s hostile to life as we know it, or if it might be a good place for life,” said Geronimo Villanueva, a planetary scientist at NASA’s Goddard Spaceflight Center and lead author of the other paper, in the same release.
Studying our solar system’s planets and moons is just one of the many, many jobs undertaken by the Webb Space Telescope since the observatory began science observations in July 2022. Many more takeaways will follow, but for the up-close-and-personal view of Jupiter’s moons we’ll have to wait until the end of the decade. | Chemistry and Material Sciences |
Exploring the lunar south pole: Lessons from Chandrayaan-3
On August 23 the Indian Space Research Organisation (ISRO) successfully landed a spacecraft on the moon's south pole, a location that has always been of particular interest to scientists due to the unique conditions created by the planet's extremities.
The moon rover, Chandrayaan-3, which recently completed its 14-day mission, made history by landing on the lunar south pole. Dr. Laura McKemmish, an astrochemist from UNSW Sydney, explains the significance of the mission and what the future holds for lunar exploration.
"This is the first landing of India on the moon, and it will make India the fourth country ever to land on the moon," says Dr. McKemmish. "The ability of our global civilization to go into space exploration is really, really crucial to enable humankind as a global community to explore elsewhere in the universe."
Interest in the southern pole of the moon stems primarily from the fact that scientists have been aware of the presence of frozen water there, and locating water is a large part of Chandrayaan-3's mission. "Identifying frozen bodies of water on the moon is a really important gateway for further space discovery in our solar system."
Navigating craters, darkness and extreme temperatures
Following a failed mission to land on the moon in 2019, India joined the US, China and the Soviet Union as only the fourth country to reach this milestone.
Chandrayaan means "moon vehicle" in Hindi and Sanskrit. The vehicle took off from a launch pad in southern India on July 14 and completed a 'soft landing' on the moon nine days later. A soft landing is when the space shuttle is kept intact.
Attempts by various space agencies have been made to land on the south pole of the moon, but it's notoriously difficult to do, thanks to rugged terrain, extreme temperatures, lack of light and communication difficulties.
"Humans have been landing on the equator of the moon for more than half a century," says Dr. McKemmish. "And while a soft landing is always more technical, when the landscape is more cratered, such as it is at the south pole, that landing becomes even harder. There's also increased complexities with communication at the poles, compared to the equator."
Chandrayaan–3 will be running a series of experiments including a spectrometer analysis of the mineral composition of the lunar surface.
"Generally a moon rover will be digging up samples, taking lots of photos, and taking various spectral readings investigating how the material interacts with light," says Dr. McKemmish.
"For this mission, the spectroscopic technique used is basically focusing a laser on the surface, causing the moon rocks to become a plasma. This plasma emits colors of light depending on its composition and thus this measurement tells us a lot about the geology and history of the rock."
Already, this technique has been used to measure the presence of aluminum, silicon, calcium, iron and sulfur on the surface of the moon, as confirmed by ISRO.
Since the moon rover has completed its walk, scientists will be analyzing data looking for signs of frozen water.
Using water to make rocket fuel
Water ice has already been definitively confirmed at the poles of the moon.
"If you think of most of the surface of the moon, it goes in and out of sunlight, making the temperature range quite large," says Dr. McKemmish. But the water at the poles has been detected in the shadows of craters, where the temperatures never reach above -250 degrees Fahrenheit, and due to the minimal tilt of the moon's rotation axis, sunlight never reaches these regions.
Initially, scientists from the University of Hawaii, Brown University and NASA used data from an instrument that was on board the Chandrayaan-1 spacecraft, launched in 2008 by the ISRO, that was uniquely equipped to confirm the presence of solid ice on the moon, without landing on it.
"Scientists first looked for water by studying the surface, as it reflects light in a different way to other geology. This was corroborated when they shone infrared light down. That's light that emits at a lower energy than our visible light, and water absorbs it at a characteristic frequency."
Water not only supports life, and could be used by astronauts stationed permanently on the moon—but it also has other important uses.
"Water can be broken down into hydrogen and oxygen," says Dr. McKemmish. "As well as allowing us to breathe, oxygen has some other essential ways in which it can support humans. In particular, oxygen and hydrogen together are a fuel that can power spacecraft built from material on the moon to missions to other parts of the solar system."
Use of moon-based material and fuel is significant because getting anything from Earth's gravitational pull up into space is really expensive, as it requires a huge amount of energy.
"Anything that you can create or find on somewhere like the moon, which has much lower gravity, means it's much cheaper and this could make it far easier to pursue a human mission to Mars.
"This work is building towards a permanent base on the moon, like how there is permanent human presence on the International Space Station. It's about moving towards constructing spacecraft in orbit, because it's a lot cheaper if we can do things in space."
Lessons from Chandrayaan-3
While this mission has been a historic moment in itself, it has also acted as a gateway to further discovery.
As Dr. McKemmish explains, exploring the south pole of the moon is exploring a new region of the planetary surface. "If you think about Earth, Antarctica is completely different than the middle of the Australian desert, which is completely different from the Amazon rainforest.
"And obviously, life creates some of this variation. But even without life, there's a lot of variability on earth, and that tells us a lot of interesting things about the history."
Dr. McKemmish emphasizes that the surface of the moon is not all homogenous. "It is fascinating scientifically to understand the diversity of the moon's different environments, but it is also important economically. Beyond the crucial presence of water in the south pole regions, we are really interested in knowing if there are regions near these water deposits that are particularly metal rich. This would be a perfect location for a future moon base."
Importantly, it's also telling a story where space isn't dominated by a few countries, but invites a more global community into exploring space. Since the Chandrayaan–3 spacecraft mission, the ISRO has already launched a rocket to study weather patterns from the sun.
"Australia is a reasonably small country worldwide, and we thought it was important enough to create a space agency," says Dr. McKemmish. "In fact, the Australian Space Agency is launching a moon rover on the Artemis mission as soon as 2026. And you can even take a crack at naming the spaceship."
Provided by University of New South Wales | Chemistry and Material Sciences |
On the Orion arm of the Milky Way galaxy, around 93 million miles (150 million kilometres) from the yellow dwarf star it orbits, is a medium-sized rocky planet. At the edge of a vast southern ocean, are the gently lapping waters of a hot-pink lake. With snow-white, crystalline shores, and more than 38 times the salt concentration of pickled olives, among its sole inhabitants are a kind of obscure life with a striking purple hue. These primitive microorganisms are decidedly alien-like: not quite bacteria, but not exactly like anything else either, they are able to thrive in conditions that seem utterly inhospitable.
This planet is, of course, Earth – and the lake is found on the southern coast of Western Australia. But the purple "halobacteria", which help to ensure the waters of Lake Hillier remain permanently Barbie-pink are also thought to hold clues to finding a certain kind of life on more distant worlds: alien vegetation.
Over the last three decades, astronomers have identified 5,528 planets outside our own solar system – a medley of weird worlds, ranging from one so dark, it's trapped in an eternal night (TrES-2 b), to a poltergeist planet that orbits an undead star (PSR B1257+12 b). And in the not-too-distant future, astronomers are confident that – if there is indeed life beyond Earth – they'll be able to spot the unmistakable signature of extraterrestrial photosynthesis.
Alien plants are expected to be every bit as peculiar as you would imagine: forests of black trees under skies with multiple suns; growths of alien shrubs that all lean in one direction, amid a permanent sunset; carnivorous undergrowth that can swallow up other alien life-forms whole.
A planet of plants
Whether aliens resemble sophisticated jellyfish-beings, three-headed beetles, or they're so unfathomably strange they defy imagination, there are some rules for their biology laid down by physics. And one thing is certain: to resist the irrepressible pull of entropy – which wants to pull living organisms apart, atom-by-atom – they're going to need a source of energy. There are only three known ways to extract this resource from the environment. Extraterrestrials could obtain it directly, trapping it from sunlight, like plants do, or by using inorganic chemicals, like bacteria at hydrothermal vents do. Alternatively, they could take a shortcut – and simply devour another organism that has already done one of those things, like animals do.
Three billion years ago, it’s thought that the entire Earth may have been tinged purple thanks to the vegetation growing at the time (Credit: Getty Images)
On Earth, the vast majority of life – by weight, at least – has run with the first option. It's been estimated that out of the 550 gigatonnes of carbon bound up in living organisms today, 450 gigatonnes are found in vegetation. What if most life in the Universe is photosynthetic? Is it possible that, in fact, our quest for intelligent civilisations has been misguided – and we should have been looking for flora, not fauna, all along?
"We know that on our planet, photosynthesis has been successful since almost the beginning of life," says Nancy Kiang, a biometeorologist at Nasa's Goddard Institute for Space Studies in New York City. "…and it's expected that it could become a successful process on another planet."
However, finding this otherworldly vegetation could prove to be tricky.
A clever experiment
On 8 December 1990, a shiny metallic object skimmed past the Earth and pointed its instruments at us. This was the Galileo spacecraft, and it began taking a series of measurements with an extraordinary goal: to see if there was life on our planet. Then it disappeared into the depths of our Solar System.
The experiment was thought up by the American astronomer Carl Sagan, and the idea was simple – if humanity was encountering the Earth for the first time from space, could we detect unmistakeable signs of life without dropping down for a visit? Galileo sent back data from equipment designed to measure various wavelengths of electromagnetic radiation – such as UV and infra-red light – and revealed some promising signals. These, in turn, can teach us how to find life on more distant worlds.
Though plants look obviously green to the human eye, they have another characteristic that is, in fact, more striking
For one thing, Sagan found that there was an abundance of oxygen, a possible sign that photosynthesis was taking place. The oxygen in the Earth's atmosphere is constantly being removed by geological and chemical processes, so it was thought to be an unambiguous marker of biological activity by plants – if they weren't always producing it, it would get mopped up. However, it now seems that this is not always the case; more recent research has found that empty planets might also sometimes have oxygen. So to be sure that oxygen is being made by plants, we'll need something else.
Another sign of life, as the Galileo spacecraft looked upon planet Earth, was a particular pigment found widely distributed across its surface. That was chlorophyll – again, Sagan had detected signs of vegetation. However, it didn't appear as you might expect. Though plants look obviously green to the human eye, they have another characteristic that is, in fact, more striking – and easier to spot from space. This is the way they absorb a lot of red light, but not infrared. "Plants are very highly reflective in the near infrared," says Kiang. Light in this band of the spectrum just isn't as "delicious" to vegetation – it prefers shorter wavelengths. This rapid change in the wavelengths it absorbs is known as the "red edge".
One way to find plants on alien planets is to simply copy this experiment, and search for a "red edge" on their surfaces. But it might not always be that straightforward. It's thought that land plants evolved around 500 million to 725 million years ago, so the Earth has only been smothered with green vegetation for around a ninth of its history. For the rest of the time, there either was no life or it had different reflective characteristics.
On some exoplanets, the vegetation could be green, yellow red – or even pink – all year-round (Credit: Nasa/Caltech/T Pyle (SSC))
This may also be the case on other planets. One possibility is that alien worlds also have light-harvesting organisms with a "red edge" equivalent, but that it happens at other wavelengths. In fact, there's no reason that alien life would need to rely on chlorophyll to capture energy from its star.
Early in the Earth's history, some experts believe that the dominant life may have been halobacteria like those found at Lake Hillier. Around three billion years ago, the entire planet may have been tinged purple by these microorganisms, which capture energy from the Sun using the primitive pigment retinal. This pigment absorbs light at wavelengths that chlorophyll does not – and has its own version of the "red edge".
An uncanny assemblage
Each year, towards the end of September, the vast swathes of birch, aspen and mountain ash forest that surround Lapland in Finland abruptly turn canary-yellow – an arctic autumn spectacle the nation calls "ruska". It's all down to the normal process of deciduous plants losing their chlorophyll as they prepare to hibernate during the winter. But it's thought that the vivid colours that appear across cooler regions of the globe each autumn may provide a glimpse into the striking scenery found on some alien planets all year-round.
There are many different photosynthetic pigments on Earth, which come in a kaleidoscopic palette of colours. But they're not adopted by organisms at random: each works best in a specific range of environmental conditions. So, back in 2007, Kiang asked – could they use this information to predict what plants would look like on other worlds?
Maybe my students, before they retire, might actually have the opportunity to directly image possibly habitable planets – Nancy Kiang
Together with colleagues from Nasa, Kiang began by studying the pigments found in Earthly organisms that harvest energy from the Sun – such as bacteria, lichens and plants. Then they combined their findings with their knowledge about the light emitted by certain types of stars.
The scientists found that on planets orbiting hotter stars than our Sun, plants would absorb more blue light, and less in the green, yellow and red parts of the spectrum – so they may have surprisingly autumnal colouring. On the other hand, vegetation that lives near a dimmer, cooler star such as a red dwarf would attempt to capture all the light it could get, so it's possible it would appear black.
A long wait
Though there is no shortage of ideas about how to spot plants on alien worlds, there is a catch. Currently the main way to view Earth-like exoplanets is via "transits" – when they pass between the star they're orbiting and the Earth. This dims the light of their sun slightly, creating a kind of shadow that can then be detected using a telescope. At the moment, it's rare for astronomers to be able to view the light reflected off planets directly – they're simply too far away, and their dim light is usually swamped by the brilliance of their star.
Kiang explains that these limitations are likely to remain for at least the next two decades. The game-changer will be the launch of the Habitable Worlds Observatory, a space telescope that scientists plan to use to take the first direct images of exoplanets. "But we are where we are now… Maybe my students, before they retire, might actually have the opportunity to directly image possibly habitable planets," says Kiang.
On some alien planets, trees might be all-black because they would need to capture light across the spectrum (Credit: Getty Images)
In the meantime, there are some workarounds.
One is to analyse the light coming from the planet's star, instead of the light from the planet itself – starlight that has passed through a planet's atmosphere can hint at the chemistry it encountered on the way. Recently, scientists were able to detect signatures that might indicate the presence of life on the planet K2-18b using this method – though it's 1.1 quadrillion km (0.68 quadrillion miles) away.
The trick could also be used to find oxygen, which would hint at photosynthesis. But it's no substitute for the real deal, and can't be used to find the light-capturing pigments that would provide a more reliable indicator of the presence of alien plants.
Another possibility will be to use the Extremely Large Telescope – currently a half-built frame set atop a remote mountain in the Atacama Desert of northern Chile. This instrument is expected to be ready by 2028, and will capture 13 times more light than any other in operation today. Kiang explains that it probably won't be able to image Earth-like planets directly. However, it should be able to capture some promising planets.
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Usually, the most likely planets for harbouring extraterrestrial life, including vegetation, are expected to be between half the size of Earth and one-and-a-half times as large. But it is thought that some "super-Earths" – even ones that occupy lonely corners of space far from their host star – might be surprisingly habitable, with thick atmospheres and around the right amount of gravity to host life.
These strange worlds are around twice as large as the Earth and have up to 10 times more mass. According to one analysis, the planets – which are unlike any in our solar system – may have hydrogen-based atmospheres. If there's extraterrestrial vegetation, it's possible that it might rely on an alien type of photosynthesis, in which the plants "breathe" by taking in methane rather than carbon dioxide.
Even in the absence of images, some planets are already seen as promising.
In 2016, astronauts grew zinnias aboard the ISS – but they may not have been the first flowers to bloom in space (Credit: Nasa/Scott Kelly)
Around 40 light years from Earth, locked into the orbit of a cool red dwarf star, are seven small rocky worlds. The Trappist-1 solar system is famous for its unusually high number of small rocky planets that may be habitable. "This is a tremendous discovery," says Kiang.
Two of the Trappist-1 planets are in the so-called Goldilocks zone – they're not too close or too far from their star, so they have just the right amount of radiation to host liquid oceans. In fact, these alien worlds have hundreds of times more water than the Earth, so they might resemble blue marbles too. However, if they contain alien plant-life, it might not be easy to discover it. It's thought that they receive too little light for photosynthesis to be as productive as it is on Earth, so they may not have detectable amounts of oxygen in their atmospheres.
If humans do detect extraterrestrial photosynthesis in the near future, it might be happening on planets occupied solely by weird vegetation – but perhaps we will also find other life too. After all, on Earth, there are around 8.7 million different species of plants and animals. What are the chances each habitable exoplanet will just have one or two?
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From asteroids to alien annihilation, Hollywood disaster movies have envisioned just about every possibility for how the world might end.
But if some of these apocalyptic scenarios seem a little far-fetched, it turns out there's a much more sinister threat from space that is actually rooted in science.
This rare and mysterious type of cosmic explosion has the potential to eradicate life on Earth for 'thousands of years', a new study has warned.
Although not quite as violent as a supernova, a kilonova occurs when two neutron stars or a neutron star and a black hole collide and merge, producing a blast of gamma rays that lasts just a matter of seconds.
'We found that if a neutron star merger were to occur within around 36 light-years of Earth, the resulting radiation could cause an extinction-level event,' Haille Perkins, a scientist at the University of Illinois Urbana-Champaign, told Space.com.
Firstly it's important to point out that the risk of such an explosion happening within that distance is very low — the nearest known neutron stars are more than 400 light-years from our planet.
But the reason it could wipe out humanity, scientists say, is because the type of radiation caused by gamma rays carries enough energy to strip electrons from atoms in a process called ionization.
Once the rays reached us, they could destroy the Earth's ozone layer and expose us to lethal doses of ultraviolet radiation from the sun for thousands of years.
However, the explosion would have to take place within 36-light years of our planet for the gamma rays to extend that far.
'The specific distance of safety and component that is most dangerous is uncertain as many of the effects depend on properties like viewing angle to the event, the energy of the blast, the mass of material ejected, and more,' Perkins added.
'With the combination of parameters we select, it seems that the cosmic rays will be the most threatening.'
The reason kilonovas are so intriguing is because of both how rare and rapid they are, making it difficult to study them.
In fact, only this week researchers at the University of Warwick revealed that they had been able to use NASA's James Webb Space Telescope to analyse a kilonova for the first time.
This allowed them to study the heavy elements being produced by the explosion, including confirmation that kilonovas do indeed create Tellurium — which had been hypothesised but never proven until now.
The new study by the University of Illinois Urbana-Champaign, meanwhile, was based on a different neutron star merger about 130 million light-years away, which is the only kilonova ever seen in electromagnetic radiation and heard in gravitational waves.
As well as the risk of stripping our planet of its atmosphere, the experts found that jets of gamma rays coming from the merger of neutron stars had the potential to destroy anything in their path at a distance of 297 light-years.
However, it would take a 'direct hit' from a jet for this to happen, meaning this particular threat is even less likely than the gradual eating away at Earth's atmosphere.
One final risk associated with kilonovas is another knock-on effect caused by the gamma ray jets.
As they move through space they collide with the gas and dust around stars which in turn creates powerful X-ray emissions called the X-ray afterglow.
Such radiation is longer lasting than gamma ray emissions, the researchers behind the new study said, and also has the potential to damage Earth's ozone layer.
The good news, however, is that to be a threat such an explosion would have to occur even closer to our planet than the 36 light-years distance for gamma rays — within 16.3 light-years to be exact.
All in all, the researchers said, solar flares, asteroid impacts and supernova explosions all have a 'better chance of being harmful' to Earth than kilonovas.
'Neutron star mergers are extremely rare but quite powerful, and this, combined with the relatively small range of lethality, means an extinction caused by a binary neutron star merger should not be a concern of the people on Earth,' Perkins said.
The new research has been published to the preprint database arXiv. | Chemistry and Material Sciences |
NASA/JPL-Caltech
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New analysis has found a source of carbon within Europa, Jupiter's moon that is believed to hold massive amounts of liquid water. This view of the moon was created from images taken by NASA's Galileo spacecraft in the late 1990s.
NASA/JPL-Caltech
New analysis has found a source of carbon within Europa, Jupiter's moon that is believed to hold massive amounts of liquid water. This view of the moon was created from images taken by NASA's Galileo spacecraft in the late 1990s.
NASA/JPL-Caltech
In an intriguing breakthrough, astronomers have concluded that carbon, an essential component of life on Earth, is also present within Europa, Jupiter's ice-covered moon that's believed to hold huge oceans of liquid salt water beneath its icy surface.
The findings come from analyzing images from NASA's James Webb Space Telescope, which found the carbon "likely originated in the subsurface ocean," according to a summary of two papers about the analysis.
"The discovery signals a potentially habitable environment in the ocean of Europa," according to the Webb telescope's website.
Signs that a building block of life is in Europa's ocean
Scientists had previously detected solid carbon dioxide on Europa's surface, but they weren't certain whether it might have come from off-moon sources, such as meteorites. The new research points to an answer — and to more questions.
"On Earth, life likes chemical diversity — the more diversity, the better. We're carbon-based life. Understanding the chemistry of Europa's ocean will help us determine whether it's hostile to life as we know it, or if it might be a good place for life," Geronimo Villanueva, lead author of one of two papers about the research, said as the findings were released. Villanueva is a planetary scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.
"We now think that we have observational evidence that the carbon we see on Europa's surface came from the ocean. That's not a trivial thing. Carbon is a biologically essential element," said Samantha Trumbo of Cornell University, who is the lead author of the second paper about carbon on Europa.
Much of the carbon dioxide was found in a region called Tara Regio, where sodium chloride — a.k.a. table salt — was spotted several years ago. Its name comes from Celtic mythology, signifying "the main royal residence of the High Kings." But planetary scientists know the region as "chaos terrain," where the landscape looks to be shattered, possibly from interactions between the icy surface and the ocean that is believed to lie beneath it.
No, it's not time to meet the new neighbors
An image of Europa's surface shows a region of "chaos terrain," where the surface has broken apart into many smaller chaos blocks that are surrounded by a featureless matrix material.
NASA/JPL-Caltech/SETI Institute
It's important to remember that in this context, a "habitable environment" on Europa refers to a salty ocean encased by an ice shell that's believed to be 10 to 15 miles thick, on a moon where the sunlight is about 25 times fainter than on Earth.
If that's not enough to make you put away your swimsuit, consider the neighborhood bully: Europa is under the thrall of Jupiter's radiation and gravity — the latter is so strong, it's believed to create tides that rip the moon's thick ice crust apart.
But NASA says tidal flexing on Europa could also produce the heat and nutrients that encourage life. So while the differences between conditions on Earth are stark, similarities, like the likely presence of carbon, are compelling. And while Europa is a bit smaller than our Moon, its ocean is estimated to hold more than twice as much water as all of Earth's oceans together.
The new findings come a year before NASA's ambitious Europa Clipper mission, which will launch in October of 2024 and reach the Jovian moon in 2030.
Europa Clipper is set to be the largest spacecraft NASA has ever developed for such a mission, mainly because it needs large solar panels to operate that far from the sun. The craft will make nearly 50 flybys of Europa, as close as 16 miles from the surface. | Chemistry and Material Sciences |
When a probe smashed into a small asteroid last year, the collision did more than change the asteroid’s orbit — it blasted a few dozen hefty boulders into space too.
Last September, NASA steered the DART spacecraft into Dimorphos, a moonlet of the larger asteroid Didymos, to test a strategy for knocking any future Earth-bound asteroids off course (SN: 10/11/22). About three months after the impact, the Hubble Space Telescope spied a halo of 37 previously unseen objects accompanying the space rock duo in their orbit around the sun, researchers report in the July 21 Astrophysical Journal Letters.
The boulders probably aren’t bits that were pulverized from larger rocks during the impact. Instead, simulations suggest they were likely intact when they were blasted off Dimorphos and could have been launched off the moonlet’s rubble-covered surface by the energy of either the collision or the seismic waves bouncing around inside it in the wake of the impact.
Still, “there’s a lot of uncertainty in such simulations,” planetary astronomer David Jewitt of the University of California, Los Angeles.
Based on the brightness of the new objects, some of the dimmest ever spied by Hubble in our solar system, Jewitt and colleagues estimate that these boulders may be as wide as 7 meters. At least 15 are larger than 4 meters across. Together, the researchers calculate, the boulders probably weigh just over 5 million kilograms — roughly the weight of 300 dump truck loads of gravel.
Repeated observations by Hubble reveal that, on average, the boulders are drifting away from Dimorphos and Didymos at about 1 kilometer per hour — a little faster than the escape velocity for the double asteroid system. So, Jewitt says, the boulders, as well as a presumed multitude of rocks too small and dim for Hubble to see, will eventually break away from the asteroid system’s orbit and circle the sun on their own. | Chemistry and Material Sciences |
A massive, gassy planet 1,300 light-years away is so hot, its clouds are made of quartz crystals. Studying it could help scientists understand more about how clouds form in extreme alien environments.
WASP-17b is a Jupiter-like exoplanet that scientists first spotted in 2009. It orbits extremely close to its star, which heats its atmosphere up to a blistering 2,700 degrees Fahrenheit (1,500 degrees Celsius). The planet itself is a bit of a lightweight; though WASP-17b's radius is about twice that of Jupiter, it has only about half Jupiter's mass. This makes WASP-17b one of the "puffiest" exoplanets discovered to date.
But astronomers recently discovered that WASP-17b's apparently fluffy clouds are hiding a secret: They're composed of tiny, solid-quartz crystals.
"We knew from Hubble observations that there must be aerosols — tiny particles making up clouds or haze — in WASP-17b's atmosphere, but we didn't expect them to be made of quartz," David Grant, an astronomer at the University of Bristol in the U.K. and first author of the study, said in a statement. "We were thrilled!"
These unexpected crystals are the first silica particles ever detected in an exoplanet's atmosphere. The researchers believe that, unlike the minuscule chips of rock that sometimes circulate in Earth's clouds, these crystals weren't swept up from WASP-17b's surface. Instead, they formed directly in its atmosphere as the result of intense heat and pressure. Based on how the crystals scatter starlight, the team estimates that each gem is about 10 nanometers across — less than one-millionth the size of an average grain of sand.
Right now, it remains unclear how pervasive these quartz clouds are across WASP-17b. The planet is tidally locked, meaning one side constantly faces its star while the other faces away. It's possible that the crystals circulate through the atmosphere on the night side, only to vaporize in the daylight.
WASP-17b's crystalline clouds are just one example of an unusual exoplanet feature discovered using JWST; in September, the telescope made news after detecting potential signs of biological life in the atmosphere of the exoplanet K2-18 b. Soon, the telescope will turn its instruments on other weird and wonderful worlds — and scientists are waiting with bated breath to see what it spots next.
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Joanna Thompson is a science journalist and runner based in New York. She holds a B.S. in Zoology and a B.A. in Creative Writing from North Carolina State University, as well as a Master's in Science Journalism from NYU's Science, Health and Environmental Reporting Program. Find more of her work in Scientific American, The Daily Beast, Atlas Obscura or Audubon Magazine. | Chemistry and Material Sciences |
NASA’s OSIRIS-REx spacecraft brought back samples from the asteroid Bennu and, in a livestream earlier today, NASA scientists showed us what it found hanging out in the great vastness of the cosmos. Simply put, the agency brought back a fairly large sample collection of various-sized rocks, dust particles and intermediate-sized particles.
The big news here is that samples from the 4.5-billion-year-old asteroid contain not only carbon, which is to be expected, but also water. These are the building blocks of life on Earth and, likely, everywhere else, so this is a big deal.
“The OSIRIS-REx sample is the biggest carbon-rich asteroid sample ever delivered to Earth and will help scientists investigate the origins of life on our own planet for generations to come,” said NASA Administrator Bill Nelson.
While space rocks and dust may seem boring to those expecting a bevy of friendly aliens, there's still plenty of time to make more fantastic discoveries. These samples have only been on the planet since September 25 and initial studies just began. NASA says they'll continue to study the particles and will create a registry of some kind so scientists from other organizations can borrow portions for a looksie. Some samples are also heading to museums.
The space agency says that the "secrets held within the rocks and dust from the asteroid will be studied for decades to come, offering insights into how our solar system was formed, how the precursor materials to life may have been seeded on Earth, and what precautions need to be taken to avoid asteroid collisions with our home planet."
Additionally, scientists were pleasantly surprised by the presence of "bonus asteroid material" covering the outside of the collector head, canister lid and base. Vanessa Wyche, director of NASA's Johnson Space Center, says that the agency is ready with additional specialized tools to "study this precious gift from the cosmos."
OSIRIS-REx actually all the way back in 2020. After that, the space vessel spent 18 months analyzing the asteroid from above before making its way back to orbit our favorite life-sustaining blue marble.
Bennu is an ancient relic of our solar system, as NASA says it was formed anywhere from 700 million to 2 billion years ago after breaking off a much larger asteroid that was originally formed over 4.5 billion years ago. Due to its older-than-Methuselah status, these Bennu fragments could actually give us a window into how life started on Earth, thanks to the carbon and water already discovered and any future findings.
This isn't the end for the curious spacecraft OSIRIS-REx. It's still out there, doing its best Jim Kirk impression. Next up? The craft's heading to an asteroid named Apophis under a new mission name, OSIRIS-APEX. | Chemistry and Material Sciences |
NASA’s mission to one of the rarest types of asteroids in the solar system is set to launch on Oct. 12 from the Kennedy Space Center after a delay over the spacecraft’s nitrogen cold gas thrusters.
"NASA is just days from launching a mission to a one-of-a-kind asteroid that may tell us how planets like our own Earth formed!" Michelle Handleman, a spokesperson for NASA’s Goddard Space Flight Center said in a statement.
The spacecraft, Psyche, will make a six-year journey to a metal-rich asteroid — also named Psyche — orbiting the sun between Mars and Jupiter. The mission plans to have the spacecraft orbit the asteroid for 26 months while mapping and studying its properties in "unprecedented detail," Handleman said.
"This asteroid is unique because it’s made of significant amounts of metal and may be the leftover core material from planetary building blocks," she added.
Psyche — 173 miles at it's longest point — is the largest of about nine asteroids in our solar system that appear to be made of mostly metal such as iron and nickel, NASA's Planetary Science Division director, Lori Glaze, said in a video.
"When planets form, the inside melts and all the heavy metals go to the middle and then the lighter rocky material goes out on the outside just like Earth, Mars and Mercury, but if there was a big impact that hit that object and blew off all of that rocky crust, it would’ve left that metal core exposed," Glaze said.
"If we go to Psyche, and it is an exposed metal core, that’s the only way we can actually see inside a planet to see what a metal core looks like," she added. "We’ve never seen anything like it before."
Psyche was named for the Greek goddess of the soul after being discovered by Italian astronomer Annibale de Gasparis on March 17, 1852, according to NASA.
The mission was delayed a week so NASA could spend more time to complete verifications of the parameters used to control the spacecraft’s gas thrusters, including adjusting them for warmer temperature predictions.
The mission is led by Arizona State University and NASA’s Jet Propulsion Laboratory is responsible for mission management, operations and navigation.
NASA plans to live stream the launch on NASA TV and social media. The agency did not immediately respond to a request for a comment.
Stephen Sorace contributed to this report. | Chemistry and Material Sciences |
UK astronomers studying the clouds of Venus have detected what they describe as a robust phosphine signal in their latest set of observations, adding to the case for alien life.
A variant of phosphorus, phosphine in these concentrations, is a strong biosignature, meaning that if found on Earth, the best explanation would be it is being made from biological life.
With further analysis to be done, the confirmation that there is (or isn’t) life in the clouds of Venus is unlikely to come before the 2030s.
Controversial Detection of Phosphine in 2020 Has Now Been Verified Multiple Times
Back in September 2020, researchers announced the first detection of phosphine gas in the clouds of Venus. The story grabbed national headlines due to the fact that the specific altitude the gas was detected was a location scientists had previously theorized had the right temperature and pressure to support certain forms of low-oxygen environment microbial life found here on Earth.
Specifically, the types of Earthling microbial life that could both produce phosphine and thrive in the environment of the Venusian clouds are part of a class of hardy organisms referred to as extremophiles for their ability to survive and even thrive in extreme environments.
Almost immediately, that detection was followed up by a failed detection, putting the original results and the hopes of finding alien life in jeopardy.
“Instead of phosphine in the clouds of Venus, the data are consistent with an alternative hypothesis: They were detecting sulfur dioxide,” said co-author Victoria Meadows, a UW professor of astronomy at the time. “Sulfur dioxide is the third-most-common chemical compound in Venus’ atmosphere, and it is not considered a sign of life.”
Undaunted, the original team reconfirmed their results with all new observations in 2022, once again hinting that the best explanation for the concentrations and altitudes of the detected phosphine was extremophiles.
“A reanalysis of the legacy data collected by the NASA Pioneer Venus Neutral Gas Mass Spectrometer (LNMS) (13) at the altitude of 51.3 km shows evidence of PH3 in the clouds of Venus,” the researchers explained. “(Furthermore) PH3 (phosphine) is the only P-containing molecule that fits the data and is in gas form at Venus’ 51.3 km altitude.”
Now, a new team of researchers says they have not only reevaluated the data that challenged the original finding, but they have also detected phosphine in a whole new set of readings, once again fostering hopes for finding the first signs of life outside of Earth.
Five Separate Readings Confirm Phosphine in Clouds of Venus
“We now have five detections over the last few years, from three different sets of instruments and from many methods of processing the data,” said Professor Jane Greaves, an astrobiologist at the School of Physics and Astronomy at Cardiff University and a member of the team who made the recent discovery. “We’re getting a clue here that there is some steady source (of phosphine), which is the point of legacy surveys—to show whether that’s true or not.”
These latest readings were the result of 50 hours of observations by the James Clark Maxwell Telescope (JCMT) in Hawaii, which took place from Feb 2022 to May 2023. Notably, the original 2020 detection consisted of eight hours of observations, making this latest detection the most robust yet.
Greaves and her team also took a fresh look at the data gathered by NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) airplane that failed to replicate the 2020 findings. But instead of failure, she says tweaking the way the data from that analysis was processed revealed that they likely detected phosphine after all.
“I did one tiny tweak to the way they looked at the data, and you can certainly get something out,” said Greaves. “I didn’t do anything elaborate—just standard techniques.”
After these latest detections and confirmations, Greaves presented the team’s findings at the National Astronomy Meeting 2023 at Cardiff University in Wales, UK.
More Observation and Future Missions Hope To Settle Extraterrestrial Life Debate
While the latest findings certainly don’t confirm the presence of life, the team says another 150 hours of observations using the JCMT are scheduled to make the detection of phosphine iron clad. Of course, the researchers concede that any irrefutable confirmation of life (or some other natural process) as the source of the phosphine is likely not to be made until missions to the planet’s atmosphere occur sometime in the 2030s.
The best bet from the upcoming missions is NASA’s DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging Plus) probe which is currently scheduled to plunge through the clouds of Venus sometime in 2031. Unfortunately, the researchers say there is a chance that DAVINCI+ won’t even allocate one of its detection tools to look for the source of the phosphine since the mission has been planned since well before the 2020 detection.
“They have four of these laser wavelengths to allocate, and only three are decided,” explained Greaves. “We made our case for phosphine, and we’re just waiting to hear back (from mission planners).”
Ultimately, the argument is likely to go until at least 2031, but until then, these latest findings are another sign that there may indeed be life in the clouds of Venus.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at [email protected]. | Chemistry and Material Sciences |
After months of anticipatioin, NASA's Psyche mission is finally set to launch today.
Following bad weather earlier this week, the US space agency will now attempt the launch at 10:19 ET (15:19 BST) today from the Kennedy Space Center in Florida.
Psyche is a spacecraft built to explore a 4.5 billion-year-old asteroid called 16 Psyche, which scientists think may be packed full of iron, nickel and gold with a value in excess of $10,000 quadrillion (£8,072 quadrillion).
That's enough money to make everyone on Earth a billionaire — although even if NASA is able to confirm this is the case, there are currently no plans to extract the precious metals.
Unfortunately, today's launch isn't set in stone, with NASA predicting a 40 per cent chance of favourable weather conditions.
If today's launch is called off, the next available launch window will be at 10:24 ET (15:24 BST) on Saturday.
Weather officials forecast a 70 per cent chance of favorable conditions for this launch opportunity.
When it does launch, the US space agency will be hosting live coverage for the public to watch.
This is due to begin at 09:15 ET (14:15 BST) today on the NASA Television media channel, while commentary will be added from 09:30 ET (14:30 BST) as the launch build-up is aired on the US space agency's YouTube, X, Facebook, Twitch and Daily Motion channels.
It will also be shown on the NASA app and the space agency's website.
Psyche's launch had already been delayed once, with the $1.2 billion (£988 million) spacecraft originally scheduled to blast into space on October 5, only for this to be put back by a week so that engineers could update the configuration of its thrusters.
HOW MUCH IS PSYCHE WORTH? If 16 Psyche is in fact loaded with precious metals, it could be worth an extraordinary amount of money, according to Dr Linda Elkins-Tanton, a space scientist at MIT. She has calculated that the iron in 16 Psyche alone would be worth $10,000 quadrillion (£8,072 quadrillion). Assuming the market for asteroid materials is on Earth, this could cause the value of precious metals to plummet, completely devaluing all holdings including those of governments, and all companies involved in mining, distributing and trading such commodities. Ultimately, it could lead to the collapse of the entire economy. Speaking to Global News Canada, Dr Elkins-Tanton said: 'Even if we could grab a big metal piece and drag it back here … what would you do? 'Could you kind of sit on it and hide it and control the global resource – kind of like diamonds are controlled corporately – and protect your market? 'What if you decided you were going to bring it back and you were just going to solve the metal resource problems of humankind for all time? This is wild speculation obviously.'
When it does reach orbit, Psyche will embark on a six-year, 2.2 billion-mile (3.6 billion-kilometre) trip to a space rock of the same name, 16 Psyche.
This 170-mile-wide (280 kilometre) asteroid sits in the main asteroid belt between Mars and Jupiter.
No spacecraft has ever visited an object like 16 Psyche – thought to have a surface containing substantial amounts of metal rather than rock or ice – but if all goes to plan the orbiter will arrive at its destination in July 2029.
The irregular and potato-like asteroid is believed to be the exposed core of a demolished protoplanet — the building blocks of the rocky planets in our solar system: Mercury, Venus, Earth, and Mars.
If so, it could provide a unique opportunity to study how planets like our own formed.
Scientists say the space rock is most likely a survivor of multiple violent hit-and-run collisions, common when the solar system was forming.
During this smash-up and merging of smaller planetesimals, the resulting bigger objects start out completely molten.
Heavy metals then sink to the core, while lighter rock floats to the top.
With 16 Psyche, however, NASA thinks that after reaching this stage it was then hit by another asteroid which stripped it of its rocky mantle and left behind a bare metal core that has been detected today.
Spectroscopic studies and radar observations suggest its surface is up to 95 per cent nickel and iron, a composition similar to that of Earth's core.
If 16 Psyche is in fact loaded with precious metals, it could be worth a huge amount of money, according to Dr Linda Elkins-Tanton, a space scientist at MIT.
She has calculated that the iron in 16 Psyche alone would be worth $10,000 quadrillion (£8,072 quadrillion).
Assuming the market for asteroid materials is on Earth, this could cause the value of precious metals to plummet, completely devaluing all holdings including those of governments, and all companies involved in mining, distributing and trading such commodities.
Ultimately, it could lead to the collapse of the entire economy.
Of course it's all speculative and hypothetical, because even if the space rock was worth anywhere close to that kind of money, it's not like it could easily be brought back to Earth and there are currently no plans to do so.
16 Psyche was actually only the 16th asteroid ever discovered, having been spotted in 1852 by Italian astronomer Annibale de Gasparis.
It has an average diameter of some 136 miles (220 kilometres) and contains about 1 per cent the total mass of the entire asteroid belt — around 440 billion billion pounds (220 billion billion kilograms) to be exact.
That makes it among the 12 largest minor planets orbiting the sun between Mars and Jupiter.
The Psyche spacecraft will carry with it several instruments, including two high-resolution cameras and a spectrometer to determine the asteroid's composition.
It also has a magnetometer to check if the space rock has a remnant magnetic field, along with an instrument to measure its gravitational field.
The orbiter will spend a total of 21 months orbiting the asteroid while capturing the first-ever images of 16 Psyche.
The hope is that by mapping and studying the asteroid in such detail it will help researchers determine how it came to be, which could in turn shed light on the formation of our own planet. | Chemistry and Material Sciences |
NASA's James Webb Telescope has detected carbon dioxide and methane in the atmosphere of exoplanet K2-18 b, a potentially habitable world more than eight times the size of Earth.
The ground-breaking discovery has led astronomers to consider the possibility that K2-18 b may belong to a unique class of exoplanets known as "Hycean" planets, which possess hydrogen-rich atmospheres and potentially water-covered surfaces, making them potential candidates for life.
The initial insights were made possible by observations from NASA's Hubble Space Telescope.
K2-18 b orbits a cool dwarf star called K2-18, around 120 light-years away from Earth, within the constellation Leo - and sits within the habitable zone.
These exoplanets, with sizes between Earth and Neptune, are not found in our solar system, making their characteristics a subject of active debate among scientists.
The idea that K2-18 b could be a Hycean exoplanet, is particularly fascinating to scientists, with some experts believing that such planets may offer favourable conditions for life to develop.
Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the study, said: "Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere.
"Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations."
The abundance of methane and carbon dioxide, coupled with the absence of ammonia, suggests K2-18 b features a hydrogen-rich atmosphere above a potential water ocean, scientists said.
Astronomers said the telescope's initial observations also hinted at the presence of dimethyl sulfide (DMS), a molecule primarily associated with microbial life such as marine phytoplankton on Earth, suggesting the possibility of biological activity on K2-18 b.
But, Mr Madhusudhan noted "more observations are needed to determine whether it is in fact DMS that we're seeing".
Read more on Sky News:
NASA manages to produce oxygen on Mars
Rare cosmic explosion spotted in red galaxy
Analysing exoplanet atmospheres presents a challenge due to the intense glare of parent stars, which obscures smaller celestial bodies.
To overcome this hurdle, the team examined the light passing through K2-18 b's atmosphere as it transited its host star.
The research is soon to be published in The Astrophysical Journal Letters, with the team intending to conduct further research.
"Our ultimate goal is the identification of life on a habitable exoplanet, which would transform our understanding of our place in the universe," Mr Madhusudhan concluded.
"Our findings are a promising step towards a deeper understanding of Hycean worlds in this quest." | Chemistry and Material Sciences |
Astronomers using NASA's powerful James Webb Space Telescope (JWST) just spotted tellurium, an element rarer than platinum is on Earth, in the aftermath of two dense stellar corpses about 1 billion light-years away. The findings could help researchers better understand the conditions in which precious chemical elements are created in the universe.
"Just over 150 years since Dmitri Mendeleev wrote down the periodic table of elements, we are now finally in the position to start filling in those last blanks of understanding where everything was made, thanks to Webb," study lead author Andrew Levan of Radboud University in the Netherlands and lead author of the study said in a statement.
Scientists suspect the now-merged neutron stars, spied on by the James Webb Space Telescope, were once garden-variety massive stars gravitationally locked in their home galaxy. When one among the pair reached the end of its life and exploded as a supernova, it appears the star blasted out of its galaxy and landed 120,000 light-years away. The second star followed suit.
Despite being kicked out of their galaxy in explosive ways, the neutron-star duo continued to be gravitationally bound, scientists say. They then merged into one body many hundred million years later — we saw that happen on March 7 of this year, to be exact.
"This type of explosion is very rapid, with the material in the explosion also expanding swiftly," said study co-author Om Sharan Salafia of INAF-Brera Astronomical Observatory in Italy.
The violent cosmic merger, known to astronomers as a kilonova, sparked a gamma-ray burst (GRB) witnessed by scientists on March 7 — the second brightest GRB since the search for these phenomena began 50 years ago. The glare was first spotted by NASA's Fermi space observatory, and lasted a record 200 seconds. Similar flashes from previous star mergers diffused within just two seconds.
Fermi, Webb and the Neil Gehrels Swift Observatory eyed the bright flash and worked toward pinpointing its source, according to the statement. Scientists say Webb's observations of the aftermath helped identify tellurium in the cloud of material surrounding the merger, marking yet another milestone in its historic mission.
"Webb provides a phenomenal boost and may find even heavier elements," said study co-author Ben Gompertz, a professor at the University of Birmingham in the U.K. The observatory "has certainly opened the door to do a lot more, and its abilities will be completely transformative for our understanding of the universe."
This research is described in a paper published Wednesday (Oct. 25) in the journal Nature. | Chemistry and Material Sciences |
Everyone’s into asteroids these days. Space agencies in Japan and the United States recently sent spacecraft to investigate, nudge, or bring back samples from these hurtling space rocks, and after a rocky start, the space mining industry is once again on the ascent. Companies like AstroForge, Trans Astronautica Corporation, and Karman+ are preparing to test their tech in space before venturing toward asteroids themselves.
It’s getting serious enough that economists published a series of papers on October 16 considering the growth of economic activity in space. For instance, a study by Ian Lange of the Colorado School of Mines considers the potential—and challenges—for a fledgling industry that might reach a significant scale in the next several decades, driven by the demand for critical metals used in electronics, solar and wind power, and electric car components, particularly batteries. While other companies are exploring the controversial idea of scooping cobalt, nickel, and platinum from the seafloor, some asteroids could harbor the same minerals in abundance—and have no wildlife that could be harmed during their extraction.
Lange’s study, coauthored with a researcher at the International Monetary Fund, models the growth of space mining relative to Earth mining, depending on trends in the clean energy transition, mineral prices, space launch prices, and how much capital investment and R&D grow. They find that in 30 to 40 years, the production of some metals from space could overtake their production on Earth. By their assessment, metallic asteroids contain more than a thousand times as much nickel as the Earth’s crust, in terms of grams per metric ton. Asteroids also have significant concentrations of cobalt, iron, platinum, and other metals. And thanks to reusable rockets developed by SpaceX, Rocket Lab, and other companies, since 2005 launch costs for payloads have plummeted by a factor of 20 or so per kilogram—and they could drop further.
One day, robots may mine minerals to be used in space, such as for building spacecraft or habitats for astronauts. But current refining methods, which extract useful metals from dirt, depend on fundamentals like gravity, Lange says. It might be better to try to find a way to bring those resources down to Earth, he says—where there would also be plenty of demand for them.
While no one has ever tried to put a price on an asteroid, critical metals get reappraised by markets every day. Cobalt currently goes for about $33,000 per ton, and nickel for $20,000 per ton. Electric vehicles and their batteries need about six times the minerals conventional cars do, and they require both nickel and cobalt in significant quantities. Nickel's also necessary for solar panels, and cobalt’s needed for wind turbines. Demand for cobalt could rise sixfold by 2050, eventually reaching a million tons per year, while demand for nickel could increase fourfold, according to the International Energy Agency, depending on how seriously governments and industries try to achieve a clean energy transition. Demand for platinum-group metals is expected to grow as well, both for catalytic converters and fuel cells.
Lange’s study also highlights the social and environmental costs of mining on Earth. The Democratic Republic of Congo accounts for 70 percent of cobalt production, for example, while nickel primarily comes from Indonesia and the Philippines, and Russia and South Africa have most of the global supply of platinum-group metals. Many mining sites in these nations have been reported for systemic use of child labor, forced labor, and human rights abuses, especially for the cobalt supply chain, according to the International Energy Agency. Indonesian nickel mining operations have also been blamed for cutting down forests and polluting water supplies.
While deep-sea mining could present the next frontier in mining these metals on Earth, that entails environmental risks like the disruption of aquatic life, noise and light pollution, and harm to ecosystems. Even the most barren patch of the ocean floor is teeming with life in comparison to asteroids, which—as far as scientists know—are lifeless rocks. Lange argues that mining asteroids will be a more acceptable trade-off to the public: “This [space] rock won’t look like it has looked for the last X million or billion years,” he says, but few people will care if no wildlife are at stake. | Chemistry and Material Sciences |
Study reveals cosmic surprises about star formation from the dawn of time
A groundbreaking international study has unveiled remarkable insights into the early evolution of galaxies, shedding light on the fundamental processes that have shaped our universe. The findings were published in Nature Astronomy.
A research team from Denmark and Australia used the extraordinary capabilities of the James Webb Space Telescope to delve back in time billions of years, to the period shortly after the Big Bang when galaxies were first forming.
Study co-author and astrophysicist Associate Professor Claudia Lagos, at The University of Western Australia node of the International Center for Radio Astronomy Research (ICRAR), said researchers found that for more than 12 billion years galaxies followed the same set of rules when it came to the formation rate of stars, as well as their mass and chemical composition.
"It was like the galaxies had a rulebook that they followed—but astonishingly, this cosmic rulebook, appears to have undergone a dramatic rewrite during the universe's infancy," Lagos said.
"The most surprising discovery was that ancient galaxies produced far fewer heavy elements than we would have predicted based on what we know from galaxies that formed later.
"In fact their chemical abundance was approximately four times lower than anticipated, based on the fundamental-metallicity relation observed in later galaxies."
Lagos said the findings challenged previous ideas about how galaxies evolved in the early universe, suggesting that early on galaxies were closely connected to the space around them and influenced by their cosmic neighborhood.
"What's most surprising is that the early galaxies continually received new, pristine gas from their surroundings, with the gas influx diluting the heavy elements inside the galaxies, making them less concentrated," Associate Professor Lagos said.
The discovery challenges existing theories about galaxy evolution and raises questions about the mechanisms at play during the universe's formative years, opening the door to further exploration about the cosmic processes that influenced the development of early galaxies.
More information: Kasper E. Heintz et al, Dilution of chemical enrichment in galaxies 600 Myr after the Big Bang, Nature Astronomy (2023). DOI: 10.1038/s41550-023-02078-7
Journal information: Nature Astronomy
Provided by University of Western Australia | Chemistry and Material Sciences |
Never-before-seen details of the Milky Way's spiral arms have been revealed through chemical mapping.
This pioneering technique, called chemical cartography, has unveiled new regions of our galaxy's stunning radial features populated by dense patches of young stars. Headed by Keith Hawkins, an assistant professor at The University of Texas at Austin, the research team's work could be crucial for astronomers seeking to understand our galaxy's evolution, shape and structure.
Chemical cartography shows the distribution of elements throughout the Milky Way — from lighter elements, such as hydrogen and helium, to heavier ones, such as carbon, nitrogen and oxygen. For context, astronomers refer to any elements heavier than helium as metals. This, therefore, allows astronomers to locate stars according to their chemical compositions rather than merely the light they emit.
Over the course of their lives, stars fuse hydrogen to create helium, then fuse that helium to create other metals. This means metal levels associated with individual stars can give astronomers information about their ages. Chemical cartography thus allowed Hawkins and fellow scientists to spot where the Milky Way's young stars are concentrated. In short, the researchers found them to be abundant in our galaxy’s spiral arms.
"Much like the early explorers, who created better and better maps of our world, we are now creating better and better maps of the Milky Way," Hawkins said. "Those maps are revealing things we thought to be true but still need to check."
Chemical cartography isn't really a new process, but only recently did scientists manage to develop telescopes with enough observing power to get significant results using the technique.
Finding where the Milky Way's hot young stars hang out
For at least seven decades, astronomers have understood that our galaxy has spiral arms that extend out from the dense concentration of stars, gas, and dust which lie at its heart, known as the "central bulge."
However, the exact shape of this striking structure — down to the number of arms our galaxy has — remains uncertain.
The difficulty in assessing the Milky Way's morphology comes from the fact that we live in it. We're basically analyzing it from the inside, with Earth sitting in the Orion Arm around two-thirds of the way from the central bulge.
We simply can't get far enough to observe our galaxy from an outsider's perspective.
"It's like being in a big city," Hawkins explained. "You can look around at the buildings and you can see what street you’re on, but it’s hard to know what the whole city looks like unless you’re in a plane flying above it."
This hasn't prevented scientists from modeling intricate models of the shape of the Milky Way, but Hawkins wanted to verify the accuracy of those models while simultaneously investigating whether chemical cartography can offer an even better view of the Milky Way's arms in general.
One traditional way of mapping the Milky Way involves monitoring the concentrations of young stars that are created as the galaxy's very dense spiral arms rotate. As this rotation occurs, it compresses gas and dust to ultimately trigger star births.
In other words, identifying an overabundance of young stars implies the location of a spiral arm.
Though young stars can be detected by tracking the bright blue light they emit, observations of this kind can be obscured by thick clouds of dust which present a challenge to even the most advanced telescopes. That means some regions of the Milky Way’s spiral arms go unobserved.
No more metal
One way of working around this dust veil is by observing exactly how metal-rich the stars that lurk in hidden regions are.
This so-called metalicity serves as an age measurement because the early cosmos was filled with hydrogen and helium, but little in the way of metals. That means the oldest stars are also composed of mostly hydrogen and helium and are thus "low metalicity" or "metal-poor."
During their lives, these older stars forge heavier elements via nuclear fusion — but when they run out of such fuel, are ripped apart by supernova explosions that spread the metals throughout their cosmic environment. Therefore, when metal-enriched clouds of dust and gas collapse to birth stars, this next generation of stars is richer in metals than the last.
This stellar cycle of life and death has continued throughout the 13.8 billion-year history of the universe, with every subsequent generation of stars being more metal-rich than the last. Thus, young stars are expected to be "metal-rich" or hold a "high metalicity."
If the Milky Way's spiral arms trigger star births as predicted, then they should be marked by young stars, aka metal-rich stars. Conversely, spaces between the arms should be marked by metal-poor stars.
To confirm this theory, as well as create his overall map of metalicity, Hawkins first looked at our solar system's galactic backyard, which include stars about 32,000 light years from the sun. In cosmic terms, that represents our stellar neighborhood's immediate vicinity.
Taking the resultant map, the researcher compared it to others of the same area of the Milky Way created by different techniques, finding that the positions of the spiral arms lined up. And, because he used metalicity to chart the spiral arms, hitherto unseen regions of the Milky Way's spiral arms showed up in Hawkins' map.
"A big takeaway is that the spiral arms are indeed richer in metals," Hawkins explained. "This illustrates the value of chemical cartography in identifying the Milky Way's structure and formation. It has the potential to fully transform our view of the Galaxy."
The future is bright for chemical cartography
To reach his conclusions, Hawkins used data from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) and the Gaia space telescope, with new data from the latter proving particularly useful.
Since Gaia launched in 2013, the spacecraft has observed around 2 billion cosmic objects allowing astronomers to considerably widen their view of the universe. It dropped its latest and third data release in June 2022, which was especially important for Hawkins’ chemical cartography because it offers the most precise and comprehensive survey of the Milky Way ever conducted.
"The sheer volume of data available from Gaia allows us to do chemical cartography at a galactic scale now," Hawkins said. "Data on both the positions for billions of stars and their chemical makeup wasn’t available until recently."
But as impressive as Gaia’s chemical data is, its observations still represent just around 1% of the Milky Way. Going forward, not only will Gaia continue to scour our galaxy collecting this data, but new telescopes are also coming online to collect data ripe for chemical cartography endeavors.
As telescope technology becomes more advanced, the power of chemical cartography will also increase, meaning astronomers stand to learn more about the structure of our galaxy and its previously obscured regions.
The Milky Way and its chemical composition will thus deliver insights that can be applied to other galaxies, with this new map offering a hint at the revelations that are yet to come.
“It’s a completely new era,” Hawkins concluded.
The team's research was published in the April issue of the journal Monthly Notices of the Royal Astronomical Society. | Chemistry and Material Sciences |
NASA may have discovered alien life on Mars 50 years ago when it first put its two Viking landers on the Red Planet, but the agency may have also accidentally killed it.
The claims were made by Dirk Schulze-Makuch from the Technical University Berlin, who believes an experiment carried out in the 1970s that added water to the soil drowned any life lurking in the Martian landscape.
The test, known as the Viking Labeled Release experiment, initially returned positive for metabolism, but a related investigation found no trace of organic material.
Schulze-Makuch believes the water containing a nutrient solution in the soil may have been too much liquid 'and [any life] died off after a while.'
While the theories may sound outlandish to some, this is the case for microbes living inside salt rocks in the Atacama, which has a similar landscape to Mars, that do not need rain to survive - and too much water would eradicate them.
The two landers in NASA's Viking mission touched down on Mars on July 20, 1976 (Viking 1) and September 3, 1976 (Viking 2).
The landers were equipped with a slew of instruments, including gas chromatograph/mass spectrometer, X-ray fluorescence spectrometer, seismometer, meteorology instrument, and stereo color cameras.
The devices enabled them to search for possible signs of life and study the soil and atmosphere's physical and magnetic properties.
Schulze-Makuch called the results 'puzzling' in an op-ed for BigThink, which he shared that one of the tests came back positive, and another was negative for gas exchange. Still, small amounts of chlorinated organics were identified.
The test positive for life added water to the soil to see if products of respiration and metabolism appeared.
The theory was that if life were on Mars, microorganisms would consume the nutrients and release the radioactive carbon as a gas.
In a 2007 study, the astronomy professor suggested that Martian life could have hydrogen peroxide in their cells.
'This adaptation would have the particular advantages in the Martian environment of providing a low freezing point, a source of oxygen and hygroscopicity,' Schultz-Makuch and co-author Joop M. Houtkooper wrote in the study.
'If we assume that indigenous Martian life might have adapted to its environment by incorporating hydrogen peroxide into its cells, this could explain the Viking results,' Dirk Schulze-Makuch wrote.
'If the Martian cells contained hydrogen peroxide, that would have killed them.
'Moreover, it would have caused the hydrogen peroxide to react with any organic molecules in the vicinity to form large amounts of carbon dioxide — which is exactly what the instrument detected.'
Another experiment, pyrolytic release, tested for organic synthesis also came back positive.
This test mixed carbon monoxide and carbon dioxide from Earth to see if the carbon would be incorporated into the soil.
The Viking landers detected chlorinated organics, but scientists proposed these untreated craft may have infected the planet with terrestrial ‘hitch-hikers.’
'However, subsequent missions have verified the presence of native organic compounds on Mars, although in a chlorinated form,' wrote Dirk Schulze-Makuch.
'Life on Mars could have adapted to the arid environment by existing within salt rocks and absorbing water directly from the atmosphere.
'The Viking experiments, which involved adding water to soil samples, might have overwhelmed these potential microbes, leading to their demise.'
The landers continued their missions until the final transmission to Earth on November 11, 1982 (Viking 1) and April 11, 1980 (Viking 2), but are still sitting on Mars to this day. | Chemistry and Material Sciences |
Initial studies of the 4.5-billion-year-old asteroid Bennu sample collected in space and brought to Earth by NASA show evidence of high-carbon content and water, which together could indicate the building blocks of life on Earth may be found in the rock. NASA made the news Wednesday from its Johnson Space Center in Houston where leadership and scientists showed off the asteroid material for the first time since it landed in September.
This finding was part of a preliminary assessment of NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer) science team.
“The OSIRIS-REx sample is the biggest carbon-rich asteroid sample ever delivered to Earth and will help scientists investigate the origins of life on our own planet for generations to come,” said NASA Administrator Bill Nelson. “Almost everything we do at NASA seeks to answer questions about who we are and where we come from. NASA missions like OSIRIS-REx will improve our understanding of asteroids that could threaten Earth while giving us a glimpse into what lies beyond. The sample has made it back to Earth, but there is still so much science to come – science like we’ve never seen before.”
Although more work is needed to understand the nature of the carbon compounds found, the initial discovery bodes well for future analyses of the asteroid sample. The secrets held within the rocks and dust from the asteroid will be studied for decades to come, offering insights into how our solar system was formed, how the precursor materials to life may have been seeded on Earth, and what precautions need to be taken to avoid asteroid collisions with our home planet.
Bonus sample material
The goal of the OSIRIS-REx sample collection was 60 grams of asteroid material. Curation experts at NASA Johnson, working in new clean rooms built especially for the mission, have spent 10 days so far carefully disassembling the sample return hardware to obtain a glimpse at the bulk sample within. When the science canister lid was first opened, scientists discovered bonus asteroid material covering the outside of the collector head, canister lid, and base. There was so much extra material it slowed down the careful process of collecting and containing the primary sample.
“Our labs were ready for whatever Bennu had in store for us,” said Vanessa Wyche, director, NASA Johnson. “We’ve had scientists and engineers working side-by-side for years to develop specialized gloveboxes and tools to keep the asteroid material pristine and to curate the samples so researchers now and decades from now can study this precious gift from the cosmos.”
Within the first two weeks, scientists performed “quick-look” analyses of that initial material, collecting images from a scanning electron microscope, infrared measurements, X-ray diffraction, and chemical element analysis. X-ray computed tomography was also used to produce a 3D computer model of one of the particles, highlighting its diverse interior. This early glimpse provided the evidence of abundant carbon and water in the sample.
“As we peer into the ancient secrets preserved within the dust and rocks of asteroid Bennu, we are unlocking a time capsule that offers us profound insights into the origins of our solar system,” said Dante Lauretta, OSIRIS-REx principal investigator, University of Arizona, Tucson. “The bounty of carbon-rich material and the abundant presence of water-bearing clay minerals are just the tip of the cosmic iceberg. These discoveries, made possible through years of dedicated collaboration and cutting-edge science, propel us on a journey to understand not only our celestial neighborhood but also the potential for life’s beginnings. With each revelation from Bennu, we draw closer to unraveling the mysteries of our cosmic heritage.”
For the next two years, the mission’s science team will continue characterizing the samples and conduct the analysis needed to meet the mission’s science goals. NASA will preserve at least 70% of the sample at Johnson for further research by scientists worldwide, including future generations of scientists. As part of OSIRIS-REx’s science program, a cohort of more than 200 scientists around the world will explore the regolith’s properties, including researchers from many U.S. institutions, NASA partners JAXA (Japan Aerospace Exploration Agency), CSA (Canadian Space Agency), and other scientists from around the world. Additional samples will also be loaned later this fall to the Smithsonian Institution, Space Center Houston, and the University of Arizona for public display.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Lauretta, the principal investigator, leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Littleton, Colorado, built the spacecraft, provided flight operations, and was responsible for capsule recovery. Goddard and KinetX Aerospace were responsible for navigating the OSIRIS-REx spacecraft. Curation for OSIRIS-REx, including processing the sample when it arrived on Earth, is taking place at NASA Johnson.
OSIRIS-REx is the third mission in NASA’s New Frontiers Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate at NASA Headquarters in Washington.
Find more information about NASA’s OSIRIS-REx mission at:
-end-
Shaneequa Vereen
Johnson Space Center, Houston
281-483-5111
[email protected] | Chemistry and Material Sciences |
A dwarf planet called Ceres could offer some amazing insights into our quest to discover alien life within our solar system. The small planet is located near Mars, and a new study showcases that the dwarf planet has an extensive amount of organic material present on the planet.
Ceres is located within the asteroid belt that sits between Jupiter and Mars, and while the dwarf planet plays a vital part in various science fiction stories, such as The Expanse, the dwarf planet has also been a target for scientific study because it has an insane amount of organic material on the planet.
The existence of these compounds was first identified in 2017, thanks to the Dawn spacecraft. However, recent research suggests that organic compounds on Ceres might be more widespread than expected, suggesting that Ceres could sustain signs of extraterrestrial life.
The organic material on Ceres, as well as the large amount of water ice content on the dwarf planet, suggests that it could have the essential elements to foster life beyond Earth. Scientists made the discovery by combining two different datasets, allowing the researchers to map potential organic-rich areas on Ceres that could have sustained life.
These kinds of discoveries continue to underline the significant role that organic compounds and materials play in our search for extraterrestrial life, especially as NASA’s rovers continue to find evidence of life’s building blocks on Mars.
This is an extremely exciting clue, especially given how long we have searched for any signs of life out in space. Perhaps future studies of dwarf planets like Ceres, and the life-building blocks and organic material on Mars and other planets could help us better understand how life expanded through our universe.
The new study was first presented at the Geological Society of America’s GSA Connects 2023 meeting this month, and future observations of Ceres could help us uncover more about the potential of life on the dwarf planet. | Chemistry and Material Sciences |
In August, NASA plans to deploy a high-altitude balloon that'll hunt for gamma-rays, or high-energy wavelengths produced by some of the most powerful explosions in our universe. And last week, the agency provided an update on the mission.
The novel instrument, known as ComPair, has officially been shipped off to its launch site in New Mexico as preparation for next month's liftoff.
If all goes well on the big day, ComPair will sit at a height of about 133,000 feet (40,000 m) above ground, which NASA likens to nearly four times the cruising altitude of a commercial airliner. Once locked-in-place, it'll hopefully test key technologies designed to catch signals of information-rich gamma-rays traveling across space.
Simply put, gamma-rays are invisible waveforms generated by some of the most extreme cosmic entities and interstellar scenarios you can imagine. They often stem from neutron stars, for instance, stellar bodies so dense a tablespoon of one equals something like the weight of Mount Everest. They can also be found in regions of space that house black holes, pulsars and even supernovas. Finding these rays can thus help scientists chronicle the exotic, intense objects that spit them out.
Ultimately, figuring out what space is like near these enigmas can lead to new types of physics, given that gamma-rays are found in arenas that can serve as sort of spaceborne laboratories. For example, many experts enjoy testing whether the theory of general relativity, which has a lot to do with gravitational pull, still stands strong near things like neutron stars that have unimaginably strong gravitational fields compared to the objects in our solar system.
In a way, by looking to the stars, humans can perform experiments impossible to conjure on our own planet.
It's true that gamma rays can be found on Earth, such as in lightning, but with ComPair, NASA wishes to detect these waves with specific energies between 200,000 and 20 million electron volts. That level of gamma ray power, the agency says, is typically associated with things like cosmic explosions, supermassive black holes and what're known as gamma-ray bursts. Gamma-ray bursts, in essence, refer to what many experts consider the strongest and brightest explosions in our universe, thought to be produced during the formation of black holes themselves.
"The gamma-ray energy range we’re targeting with ComPair isn’t well-covered by current observatories," Carolyn Kierans, the instrument’s principal investigator at Goddard, said in a statement. "We hope that after a successful balloon test flight, future versions of the technologies will be used in space-based missions."
One such observatory Kierans is referring to is NASA's Fermi Gamma-ray Space Telescope. Though in contrast to ComPair, Fermi observes light in the energy range between 8,000 and over 300 billion electron volts – a much wider field than the agency's upcoming gamma-ray tracker.
According to the recent press release, however, Fermi is actually how the team decoded the best range to program for ComPair's gamma-ray hunt in the first place.
The mechanism of ComPair lies in its name.
"Com" is short for Compton scattering and "Pair" is short for pair production. Both Compton scattering and pair production are basically ways of identifying and measuring gamma-rays.
In a nutshell, Compton scattering refers to how when a high-energy light particle called a photon hits another particle, such as an electron, the photon transfers some energy to whatever other particle it collides with. As gamma-rays are a form of light – they're just invisible to the human eye – this is something that's expected to happen sometimes as the rays travel through the fabric of space.
Pair production, on the other hand, refers to the event of a gamma-ray grazing the nucleus of an atom, which thereby turns the gamma-ray itself into a particle pair. One part of the resulting pair would be an electron and the other would be a positron, which you can think of as an antimatter electron. It's just that, unlike an electron, a positron has a positive charge.
For this reason, positrons are also sometimes called anti-electrons – and yes, there are also anti-protons.
Returning to ComPair, there are four components on the device that're expected to work together in detecting incoming gamma-rays. They'll essentially decode whether one of those two mentioned processes have occurred, and also measure various aspects of the signal itself.
To begin, NASA explains, ComPair is fitted with an instrument featuring 10 layers of silicon detectors which can determine the general positioning of an incoming gamma-ray. Then, there's also a high-resolution calorimeter that can measure gamma-rays which have undergone Compton scattering and another calorimeter that can measure those associated with pair production.
Lastly, there's something called an anticoincidence detector. Basically, the anticoincidence detector can differentiate between whether an incoming signal is of a gamma-ray or another sort of high-energy particle beam known as a cosmic ray. In the case of the latter, the detector can tell the other instruments on ComPair to ignore the signal. Otherwise, there'd be noise in the data and probably some confusion on what we're looking at.
But for now, the next step in ComPair's journey is simply to fly up toward the void. Until August, ComPair. | Chemistry and Material Sciences |
Scientists have shared new insights regarding metal fragments recovered from the Pacific that came from outside our solar system.
Alien-hunting Harvard physicist Avi Loeb and his team published a preprint study Thursday, explaining that the properties of a meteor that crashed in 2014 'can be naturally explained.'
The researchers trawled the seafloor off the coast of New Guinea in June, finding about 700 tiny metallic spheres during the expedition, and the 57 analyzed contain compositions that are not known to be in our solar system.
The paper suggested that the properties formed when the Earth-like planet deviated from a circular orbit around a dwarf star, creating a stream of debris shooting into interstellar space.
Loeb wrote that during this event, a rocky planet's crust would melt, creating an abundance of beryllium, lanthanum and uranium, which were found in the metallic spheres pulled from the depths of the ocean.
While the new analysis points to a natural origin, Loeb suggested that abundant rare elements could have served a technological purpose.
'For example, lanthanum could have been melted from semiconductors, and uranium could have been used as fuel in a fission reactor,' he explained.
Loeb told DailyMail.com that he and his team 'plan to find out the true nature of IM1 by finding large pieces of it in our next expedition within the next nine months.'
'Does this mean that IM1 definitely originated from a natural astrophysical environment and was not a technological Voyager-like meteor manufactured by another civilization? We do not know for sure,' Loeb shared in a Medium post.
The initial analysis, released in August, revealed the rare properties of the meteor-like object called IM1.
The paper shared that while the elements are found on Earth, the patterns do not match the alloys found on our planet, moon, Mars or other natural meteorites in the solar system.
And the pre-printed paper delves deeper into their origin.
The team calculated the speed at which the rocks launched from the Earth-like planet's crust during the event known as tidal disruption.
Loeb wrote that 'the most abundant planetary systems launch rocks from the crust of an Earth-like planet with a characteristic interstellar speed of about 37 miles per second.
In one second, the rocks covered the same distance as a car driving along a highway for one hour.
'Their speed is higher than 95 percent of the random speeds of stars in the vicinity of the Sun,' wrote Loeb.
'Amazingly, this was the speed inferred for the first reported interstellar meteor, IM1, measured by US government satellites on January 8, 2014.'
The 'BeLaU' composition found in the fragments results from the rocky planet making many close-in passages around the dwarf star, which would cause melting of the planet's surface.
'This melting could yield differentiation of elements, allowing elements with affinity to iron to sink to the planet’s iron core, Loeb shared.
'The unusually high material strength of IM1 might have resulted from the hardening associated with repeated episodes of melting and crusting and enhanced elemental differentiation compared to solar system planets like the Earth or Mars, which went through a magma ocean episode only during their early formation, as a result of bombardment by other objects.'
While the new analysis suggests IM1 had natural origins, Loeb is not ruling out the idea aliens could have fashioned it.
He and his team are planning a second expedition to the Pacific Ocean to scour the seafloor for larger pieces of IM1 'and check whether it was a rock or a more exotic object,' Loeb wrote.
For years, Loeb has argued that interstellar technology may have visited Earth.
In 2017, an interstellar object named Oumuamua passed through the Solar System.
While most scientists believe it was a natural phenomenon, Loeb famously argued it may have been of alien origin.
After discovering Oumuamua in 2017, Loeb theorized - despite much criticism - that more interstellar objects had likely whizzed past Earth.
He was vindicated in 2019 when a student discovered that a high-speed fireball in 2014, the IM1 meteor, also had interstellar origins, predating Oumuamua.
The first mission to find remnants of the 2014 meteor lasted for two weeks in June.
Also known as CNEOS1 2014-01-08, the object had an estimated diameter of 1.5 feet, a mass of 1,014 pounds and a pre-impact velocity of 37.3 miles per second.
IM1 withstood four times the pressure that would typically destroy an ordinary iron-metal meteor — as it hurtled through Earth's atmosphere at 100,215 miles per hour.
Roughly two dozen people, including scientists with Harvard's Galileo Project Expedition, the ship's crew and documentary filmmakers chronicling the endeavor, set sail from the island town of Lorengau on June 14 onboard the Silver Star.
Throughout their two-week Pacific voyage, the Galileo team scoured the seabed for signs of IM1 debris, dragging a deep-sea magnetic sled along the fireball's last known trajectory and completing 26 runs along the sea floor. | Chemistry and Material Sciences |
Nasa's Osiris-Rex capsule will come screaming into Earth's atmosphere on Sunday at more than 15 times the speed of a rifle bullet.
It will make a fireball in the sky as it does so, but a heat shield and parachutes will slow the descent and bring it into a gentle touchdown in Utah's West Desert.
The capsule caries a precious cargo - a handful of dust grabbed from asteroid Bennu, a mountain-sized space rock that promises to inform the most profound of questions: Where do we come from?
"When we get the 250g (9oz) of asteroid Bennu back on Earth, we'll be looking at material that existed before our planet, maybe even some grains that existed before our Solar System," says Prof Dante Lauretta, the principal investigator on the mission.
"We're trying to piece together our beginnings. How did the Earth form and why is it a habitable world? Where did the oceans get their water; where did the air in our atmosphere come from; and most importantly, what is the source of the organic molecules that make up all life on Earth?"
The prevailing thinking is that many of the key components were actually delivered to our planet early in its history in a rain of impacting asteroids, many of them perhaps just like Bennu.
Engineers have commanded the final adjustments to the Osiris-Rex spacecraft's trajectory. All that remains is to make the "go, no-go" decision to release the capsule to fall to Earth this weekend.
The quest to acquire fragments of Bennu began in 2016, when Nasa launched the Osiris-Rex probe towards the 500m (1,640ft) wide object. It took two years to reach the body and a further two years of mapping before the mission team could confidently identify a location on the space rock's surface to scoop up a "soil" sample.
Key to that choice was the British rock legend and astrophysicist Dr Sir Brian May. The Queen guitarist is an expert in stereo imaging.
He has the ability to align two pictures of a subject taken from slightly different angles to give a sense of perspective - making a 3D view of a scene. He and collaborator Claudia Manzoni did this for the shortlist of possible sample sites on Bennu. They established the safest places to approach.
"I always say you need art as well as science," Sir Brian told BBC News. "You need to feel the terrain to know if the spaceship is likely to fall over or if it will hit this 'rock of doom' that was right on the edge of the eventual chosen site, called Nightingale. If that had happened it would have been disastrous."
The moment of sample capture, on 20 October 2020, was astonishing.
Osiris-Rex lowered itself down to the asteroid - holding its grabbing mechanism on the end of a 3m-long (10ft) boom.
The idea was to slap the surface and, at the same time, give out a blast of nitrogen gas to kick up gravel and dust. What happened next was something of a shock.
When the mechanism made contact, the surface parted like a fluid. By the time the gas fired, the disc was 10cm (4in) down. The nitrogen pressure blasted a crater 8m (26ft) in diameter. Material flew in all directions, but crucially also into the collection chamber.
And so now here we are. Osiris-Rex is just hours away from delivering the Bennu sample at the end of what has been a seven-year, seven-billion-kilometre round trip.
Once the capsule is safely on the ground, it will be whisked off to the Johnson Space Center in Texas, where a dedicated cleanroom has been built to analyse the samples.
Dr Ashley King from London's Natural History Museum (NHM) will be one of the very first scientists to get his gloves on the material. He is part of the "quick look" team that will do the initial analysis.
"Bringing back samples from an asteroid - we don't do that very often. So you want to do those first measurements, and you want to do them really well," he says. "It's incredibly exciting."
Nasa regards Bennu as the most dangerous rock in the Solar System. Its path through space gives it the highest probability of impacting Earth of any known asteroid. But don't panic, the odds are very low - akin to tossing a coin and getting 11 heads in a row. And any impact isn't likely until late next century.
Bennu probably contains a lot of water - as much as 10% by weight - bound up in its minerals. Scientists will be looking to see if the ratio of different types of hydrogen atoms in this water is similar to that in Earth's oceans.
If, as some experts believe, the early Earth was so hot that it lost much of its water, then finding an H²O match with Bennu would bolster the idea that later bombardment from asteroids was important in providing volume for our oceans.
Bennu probably also contains about 5-10% by weight of carbon. This is where a lot of the interest lies. As we know, life on our planet is based on organic chemistry. As well as water, did complex molecules have to be delivered from space to kickstart biology on the young Earth?
"One of the very first analyses to be done on the sample will include an inventory of all of the carbon-based molecules that it contains," says the NHM's Prof Sara Russell.
"We know from looking at meteorites that asteroids are likely to contain a zoo of different organic molecules. But in meteorites, they're often very contaminated, and so this sample return gives us a chance to really find out what the pristine organic components of Bennu are."
Prof Lauretta adds: "We've actually never looked for the amino acids that are used in proteins in meteorites because of this contamination issue. So we think we're really going to advance our understanding of what we call the exogenous delivery hypothesis, the idea that these asteroids were the source of the building blocks of life."
Additional reporting by Rebecca Morelle, Alison Francis and Kevin Church | Chemistry and Material Sciences |
Asteroid dust caused 15-year winter that killed dinosaurs: Study
Around 66 million years ago, an asteroid bigger than Mount Everest smashed into Earth, killing off three quarters of all life on the planet—including the dinosaurs.
This much we know.
But exactly how the impact of the asteroid Chicxulub caused all those animals to go extinct has remained a matter of debate.
The leading theory recently has been that sulfur from the asteroid's impact—or soot from global wildfires it sparked—blocked out the sky and plunged the world into a long, dark winter, killing all but the lucky few.
However research published Monday based on particles found at a key fossil site reasserted an earlier hypothesis: that the impact winter was caused by dust kicked up by the asteroid.
Fine silicate dust from pulverized rock would have stayed in the atmosphere for 15 years, dropping global temperatures by up to 15 degrees Celsius, researchers said in a study in the journal Nature Geoscience.
Back in 1980, father-and-son scientists Luis and Walter Alvarez first proposed that the dinosaurs were killed off by an asteroid strike that shrouded the world in dust.
Their claim was initially met with some skepticism—until a decade later when the massive crater of Chicxulub was found in what is now the Yucatan Peninsula on the Gulf of Mexico.
Now, scientists largely agree that Chicxulub was to blame.
But the idea that it was sulfur, rather than dust, that caused the impact winter has become "very popular" in recent years, Ozgur Karatekin, a researcher at the Royal Observatory of Belgium, told AFP.
Study co-author Karatekin said this was because the dust from the impact was thought to be the wrong size to stay in the atmosphere for long enough.
For the study, the international team of researchers was able to measure dust particles thought to be from right after the asteroid struck.
'Catastrophic collapse'
The particles were found at the Tanis fossil site in the US state of North Dakota.
Though 3,000 kilometers (1,865 miles) away from the crater, the site has preserved a number of remarkable finds believed to be dated from directly after the asteroid impact in sediment layers of an ancient lake.
The dust particles were around 0.8 to 8.0 micrometers—just the right size to stick around in the atmosphere for up to 15 years, the researchers said.
Entering this data into climate models similar to those used for current-day Earth, the researchers determined that dust likely played a far greater role in the mass extinction than had previously been thought.
Out of all the material that was shot into the atmosphere by the asteroid, they estimated that it was 75 percent dust, 24 percent sulfur and one percent soot.
The dust particles "totally shut down photosynthesis" in plants for at least a year, causing a "catastrophic collapse" of life, Karatekin said.
Sean Gulick, a geophysicist at the University of Texas at Austin and not involved in the research, told AFP that the study was another interesting effort to answer the "hot question"—what drove the impact winter—but did not provide the definitive answer.
He emphasized that discovering what happened during the world's last mass extinction event was important not just for understanding the past, but also the future.
"Maybe we can better predict our own mass extinction that we're probably in the middle of," Gulick said.
More information: Cem Berk Senel et al, Chicxulub impact winter sustained by fine silicate dust, Nature Geoscience (2023). DOI: 10.1038/s41561-023-01290-4
Journal information: Nature Geoscience
© 2023 AFP | Chemistry and Material Sciences |
Research explores the properties of supernova remnant 1E 0102.2–7219
Using the Australia Telescope Compact Array (ATCA) and the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers has observed a supernova remnant known as 1E 0102.2–7219. Results of the study, presented October 27 in the Monthly Notices of the Royal Astronomical Society journal, shed more light on the properties and nature of this remnant.
In general, supernova remnants (SNRs) are diffuse, expanding structures resulting from a supernova explosion. Observations show that SNRs contain ejected material expanding from the explosion and other interstellar material that has been swept up by the passage of the shockwave from the exploded star.
Discovered in 1981, 1E 0102.2–7219 (or E0102 for short) is a young core-collapse SNR in the Small Magellanic Cloud (SMC)—a dwarf galaxy orbiting the Milky Way. It showcases a bright, filled ring-like structure with an outer edge that traces the forward-moving blast wave. Previous observations have found that E0102 has an age of 1,738 years and its progenitor mass is estimated to be most likely between 32 and 50 solar masses.
Now, a group of astronomers led by Rami Z. E. Alsaberi of the Western Sydney University in Penrith, Australia, decided to investigate E0102 with ATCA and ALMA in order to get more insights into its properties.
"Here, we present new high-resolution and high-sensitivity radio-continuum observations of E0102 obtained from ATCA and ALMA," the researchers wrote in the paper.
The observations found that E0102 shows a ring morphology with a mean radius of about 20.2 light years and a bridge-like structure. The images also unveiled the presence of a horizontal bridge or bar-like feature in the central region of E0102 with a measured flux density of 4.3 mJy.
The mean spectral index across the entire remnant was found to be −0.54. It turned out that most areas near the circumference have a steep spectral index (of approximately −0.6) at both inner and outer radii, while indices with flat gradients are found at intermediate radii. The radio emission appears to be brightest in the north-east part of E0102.
The observations revealed that E0102 shows polarized regions in its shell and the mean fractional polarization for this remnant was measured to be 7 and 12% for 5,500 and 9,000 MHz, respectively. The data also allowed the astronomers to calculate the line-of-sight magnetic field strength in the direction of E0102, which turned out to be at a level of 44 ?G with an equipartition field of 65±5 ?G.
When it comes to the environment of E0102, the observations show an cloud of neutral atomic hydrogen (HI) towards this remnant at the velocity range of about 160–180 km/s and a cavity-like structure at the velocity of 163.7–167.6 km/s.
Summing up the results, the authors of the paper concluded that the properties of E0102 are consistent with that of a typical young SNR. They added that a relatively low integrated linear polarization of this remnant indicates a high degree of turbulence.
More information: Rami Z E Alsaberi et al, ATCA Study of Small Magellanic Cloud Supernova Remnant 1E 0102.2–7219, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad3300
Journal information: Monthly Notices of the Royal Astronomical Society
© 2023 Science X Network | Chemistry and Material Sciences |
Despite being Earth's closest celestial companion, there has long been doubt over how and when the moon formed.
Now there is evidence the moon is 40 million years older than scientists previously believed.
The most widely accepted explanation of why the moon exists is the 'giant-impact theory', suggesting that a Mars-sized planet smashed into the Earth.
The debris ejected from the collision is thought to have recombined to form the moon.
Now lunar crystals brought back from the last Apollo mission in 1972 have been used to estimate the exact age of the moon.
The crystals must have formed after the giant impact which created the moon, researchers say, because that high-energy collision melted the rock which eventually became the moon's surface - creating a magma ocean which would also have melted any crystals.
Assuming the zircon crystals came afterwards, scientists used radiometric dating, looking at the rate of decay of the crystal atoms, to work out their age.
Their results push back the age of the Moon by 40 million years, to at least 4.46 billion years old.
Professor Philipp Heck, senior author of the research, from the University of Chicago, explained why it is important to know the age of the moon, stating: 'The moon is an important partner in our planetary system - it stabilises the Earth's rotational axis, it's the reason there are 24 hours in a day, it's the reason we have tides.
'Without the moon, life on Earth would look different.
'It's a part of our natural system that we want to better understand, and our study provides a tiny puzzle piece in that whole picture.'
More than four billion years ago, when the moon is believed to have formed, our solar system was still young and the Earth was still growing.
To work out the moon's age, scientists used a sample of lunar dust brought back by Apollo 17 astronauts from the last crewed mission to the Moon in 1972.
The dust contained tiny crystals which formed billions of years ago.
Professor Heck said: 'These crystals are the oldest known solids that formed after the giant impact.
'And because we know how old these crystals are, they serve as an anchor for the lunar chronology.'
A previous study had suggested the age of the crystals, but a 'nanoscale' look at the samples was required to understand them fully.
Scientists used a method called atom probe tomography, which acts like a 'pencil sharpener' to narrow the lunar sample into a fine point, before using ultraviolet lasers to evaporate atoms from the surface of that point.
The atoms travelled through a mass spectrometer, with their speed indicating how heavy they were, and therefore their composition.
An atom-by-atom analysis showed how many of the atoms inside the zircon crystals had undergone radioactive decay, which can turn uranium into lead, for example.
By looking at the proportion of different uranium and lead atoms, called isotopes, scientists can tell how old a sample is.
The proportion of lead isotopes found indicated that the sample was about 4.46 billion years old, so the moon has to be at least that old.
Dr Jennika Greer, lead author of the study, published in the journal Geochemical Perspectives Letters, who conducted the study when she was at the University of Chicago, but is now at the University of Glasgow, said: 'It's amazing being able to have proof that the rock you're holding is the oldest bit of the moon we've found so far.
'It's an anchor point for so many questions about the Earth. When you know how old something is, you can better understand what has happened to it in its history.' | Chemistry and Material Sciences |
At 10:19 a.m. Friday, NASA launched an uncrewed spacecraft to study a metal-rich asteroid. Lessons learned from the celestial body could provide insight into the formation of planets.
The Psyche mission, named after the rocky object of interest, will spend the next six years traveling to an asteroid belt between Mars and Jupiter, where the body resides. Data suggests that the Psyche asteroid could be the exposed core of a building block of a rocky planet. It may be a metallic interior left behind after a rockey outer layer was torn away by collisions with other objects.
“There aren’t many classes of objects left in our solar system that we haven’t looked at up close with a spacecraft, and one of them that’s left is the metal asteroids,” Jim Bell, deputy principal investigator for the Psyche mission, says in a video from NASA.
But scientists won’t know for sure where Psyche originated from until they’re able to observe it up close.
“We do not know what Psyche looks like,” Psyche principal investigator Lindy Elkins-Tanton tells CNN’s Ashley Strickland. “I always joke that it’s shaped like a potato because potatoes come in many shapes, so I’m not wrong. But we’re going to find out when we get there.”
Discovered in 1852 by the Italian astronomer Annibale de Gasparis, Psyche is named after the ancient Greek goddess of the soul. It measures 173 miles across its horizontal axis and 144 miles long.
Observations from Earth suggest that the asteroid is made of a mixture of rock and iron-nickel metal. Metal likely makes up between 30 and 60 percent of its volume. If Psyche is a remnant core of a planetary building block, it could reveal to scientists what the interiors of rocky planets like Earth are like.
Psyche may be much farther from us than the center of our planet, but it’s easier to study, since we can’t drill holes to the center of Earth.
“It’s too hot, the pressure’s too high, our instruments would melt,” Bell says in NASA’s video.
“This is really an amazing opportunity that the solar system has presented to us to go and learn about this sort of fundamental building block of a planet that we can’t investigate any other way,” Sarah Noble, a NASA program scientist and planetary geologist, tells the Washington Post’s Sabrina Malhi.
The mission launch, originally scheduled for Thursday morning, was pushed back a day due to unfavorable weather conditions. NASA had a single, precise time each day through October 25 at which it could launch Psyche.
The spacecraft will now embark on its 2.2-billion-mile journey to the asteroid. In May 2026, as it approaches Mars, Psyche will use the planet’s gravity to slingshot towards the asteroid belt. The spacecraft will arrive at Psyche in August 2029 and enter into an orbit of the asteroid. It will then spend the next 26 months studying the celestial object in great detail.
The mission will investigate whether the asteroid has a magnetic field, the existence of which would support the theory that Psyche is indeed a leftover planetary core. Spectrometers will measure the asteroid’s chemical makeup, which will provide insight into its formation. An imager will study its mineral composition and topography, and the spacecraft’s telecommunication system will use radio waves to learn about Psyche’s rotation, mass and gravitational field.
It could turn out that Psyche is not a planetary building block and is instead some rare, previously unobserved object from the early solar system, according to NASA.
“It’s going to surprise us when we get there,” Elkins-Tanton tells CNN. “I think there’s a very good chance that it’s going to be outside of our imaginings, and that is my fondest hope.” | Chemistry and Material Sciences |
Abstract
The formation of stars and planets is accompanied not only by the build-up of matter, i.e., accretion, but also by its expulsion in the form of highly supersonic jets that can stretch for several parsecs1,2. As accretion and jet activity are correlated and because young stars acquire most of their mass rapidly early on, the most powerful jets are associated with the youngest protostars3. This period, however, coincides with the time when the protostar and its surroundings are hidden behind many magnitudes of visual extinction. Millimetre interferometers can probe this stage but only for the coolest components3. No information is provided on the hottest ( > 1000 K) constituents of the jet, i. e. the atomic, ionized, and high temperature molecular gas that are thought to make up the jet’s backbone. Can we detect such a high temperature spine and what is it made up of? Here we report near-infrared JWST observations of Herbig-Haro 211, an outflow from an analogue of our Sun when it was at most a few times 104 years old. These reveal copious emission from hot molecules explaining the origin of the so-called “Green Fuzzies”4–7 discovered nearly two decades ago by the Spitzer Space Telescope8. This outflow is found to be propagating slowly in comparison to its more evolved counterparts and, surprisingly, almost no trace of atomic or ionized emission is seen suggesting its spine is almost purely molecular.
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Supplementary information
The proper motions of HH211 over two decades. This video compares our JWST NIRCam 2.12 micron image of HH 211 with a corresponding one from a European Southern Observatory 8m-class telescope. The time difference is two decades and motion in the outflow is clearly observed. Note also the superior resolution achieved from space.
About this article
Cite this article
Ray, T.P., McCaughrean, M.J., Caratti o Garatti, A. et al. Outflows from the Youngest Stars are Mostly Molecular. Nature (2023). https://doi.org/10.1038/s41586-023-06551-1
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DOI: https://doi.org/10.1038/s41586-023-06551-1 | Chemistry and Material Sciences |
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NASA’s first mission to bring an asteroid sample to Earth will enter its final stretch Sunday, Sept. 24. That’s when the OSIRIS-REx spacecraft is set to drop off a capsule containing several ounces of rocky, dusty material it collected from the asteroid Bennu.
The event is scheduled to begin at 10:00 a.m. ET. Watch it live in the player above.
If the mission is a success, about a quarter of the sample will be eventually doled out to researchers across the globe. The majority of it will be archived at NASA’s Johnson Space Center alongside other extraterrestrial materials — including moon rocks and solar wind particles — and reserved for future generations of scientists.
In years to come, “Your grandchildren could write a proposal to NASA to study a piece of the sample with some new technique,” said Mike Moreau, deputy project manager for the OSIRIS-REx mission at NASA’s Goddard Space Flight Center.
NASA is set to hold a post-landing news conference around 5:00 p.m. ET. Watch it in the player above.
But before any scientists get their hands on these pieces of Bennu, the capsule that contains the sample has to touch down in the desert landscape of Utah.
Early on Sunday, researchers involved with the mission will decide whether conditions are right to follow through with the return. If they give the go-ahead, a series of ultra-precise steps should pave the way for the capsule’s safe landing at the Department of Defense’s Utah Test and Training Range.
First, the OSIRIS-REx spacecraft will release the capsule about 100,000 kilometers away from Earth, a distance that’s roughly a third of the way to the moon, Moreau said. Then, he said, the capsule will cruise through space for four hours, aiming for a mile-wide stretch of the planet’s atmosphere.
WATCH: NASA reviews plan to recover Bennu asteroid sample via OSIRIS-REx
“It’s the equivalent of throwing a dart across the length of a basketball court and hitting the bullseye,” Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center, said during an Aug. 30 news conference.
The capsule’s speed will reach 27,000 miles per hour as it enters Earth’s atmosphere, but a series of parachute deployments will slow it down to just 11 miles per hour by the time it lands in the desert, said Sandy Freund, OSIRIS-REx project manager at Lockheed Martin, at the news conference. She noted that that whole process will take just 13 minutes.
Researchers will then transfer the capsule with a sling that hangs under a helicopter to a temporary clean room for evaluation. The next day, Freund said, it’ll be shipped to its ultimate home — Johnson Space Center in Houston.
Keeping the sample free of any earthly contaminants is a top priority. Scientists at the landing site will scoop up air and soil samples from the local environment so that if something unexpected is detected in the Bennu sample, they can determine its origin, Moreau said.
Bennu is billions of years old. The asteroid dates back to the dawn of the solar system, when its planets — including Earth — were in their very infancy.
Bennu is roughly the size of the Empire State Building, Dante Lauretta, principal investigator on the mission at the University of Arizona, said in the news conference.
“It literally is a droplet made out of rock, gravel and boulder that are barely held together by their own microgravity,” Lauretta said. He added that he refers to Bennu as the “trickster” asteroid because of the many surprises it presented to the OSIRIS-REx team during their mission.
When the spacecraft first arrived at Bennu in 2018, about two years after its initial launch, researchers realized that the asteroid’s surface was covered in boulders, Moreau said. That made identifying a safe sample collection spot a challenge.
Once the team did find an ideal location — dubbed Nightingale — they expected OSIRIS-REx to pluck its sample from a solid expanse of rock, Lauretta said. But when the spacecraft made its collection attempt in 2020, Moreau said they were shocked to find the surface crumbled immediately.
“It was like jumping into a ball pit. The material is so loosely held together,” Moreau said. “And when the nitrogen gas fired [from OSIRIS-REx] to collect the sample, the whole surface disintegrated under the spacecraft.”
After OSIRIS-REx releases the capsule containing that sample in Earth’s direction, it will embark on the next leg of its journey. Though the spacecraft wasn’t initially expected to pursue a follow-up mission, researchers have planned a six-year journey that will allow it to tail another asteroid, named Apophis, when it makes a close pass by our planet in 2029.
Moreau said that Earth’s gravitational pull may influence Apophis’s physical structure as it swings by Earth, including by potentially causing landslides on the asteroid’s surface. The spacecraft — which at that point will be renamed OSIRIS-APEX — will be closely monitoring exactly what happens on the asteroid, plus analyzing its composition and properties.
Researchers believe Bennu can serve as an ancient clue to help us understand the evolution of the solar system.
The rocks and dust collected by OSIRIS-REx should shed light on what types of minerals and materials were present at the formation of asteroids like Bennu, in addition to planets including Earth, said Michelle Thompson, a planetary scientist at Purdue University. The goal, she added, is to “create an inventory for the building blocks of the solar system.”
Bennu is a carbonaceous asteroid, a category of asteroids that harbor organic molecules dating back to the early solar system. Remote analysis found hydrated minerals that contain structural water on Bennu, Thompson said, which means liquid water likely once existed on its parent body before the asteroid broke off.
That doesn’t mean there is any life on the asteroid, she emphasized. But one core theory of how life got its start on Earth posits that asteroids like Bennu helped deliver the basic ingredients when they smashed into our young planet.
READ MORE: What a NASA mission to study a metallic asteroid may teach us about Earth’s core
If life on Earth is like a brick house, Thompson explained, Bennu can tell us about the individual bricks that helped build it.
“By targeting an asteroid that hasn’t really been altered in a significant way over the history of the solar system, we can kind of take a time machine back and see what those organic molecules look like,” she said.
Thompson will be among the first few researchers to study the samples delivered by OSIRIS-REx. She specializes in planetary bodies that don’t have an atmosphere, like asteroids or the moon. Because Bennu has no shield to protect it as it travels through space, the asteroid is routinely struck by forces like solar wind and dust particles, Thompson noted.
She said she’ll focus on parts of the sample that represent the first few millimeters of Bennu’s surface, which are most affected by the asteroid’s exposure to interplanetary space. By comparing Bennu’s “skin” to more protected materials farther below, Thompson explained, she’ll be able to evaluate which characteristics of Bennu have been around since its initial formation, and which have been altered over the past several billion years.
Thompson has also worked with lunar samples brought to Earth during the Apollo missions of the 1960s and 1970s. She noted that researchers continue to learn about the moon’s evolution thanks to those materials, and that the same will be true of these pieces of Bennu, if the OSIRIS-REx mission is successful.
“As techniques have evolved, and as they’ll continue to get better in the future of the OSIRIS-REx samples, they’re really going to be like the gift that keeps on giving,” she said.
Bella Isaacs-Thomas is a digital reporter on the PBS NewsHour's science desk.
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Dec 11 | Chemistry and Material Sciences |
Scientists have been working on models of planet formation since before we knew exoplanets existed. Originally guided by the properties of the planets in our Solar System, these models turned out to be remarkably good at also accounting for exoplanets without an equivalent in our Solar System, like super Earths and hot Neptunes. Add in the ability of planets to move around thanks to gravitational interactions, and the properties of exoplanets could usually be accounted for.
Today, a large international team of researchers is announcing the discovery of something our models can't explain. It's roughly Neptune's size but four times more massive. Its density—well above that of iron—is compatible with either the entire planet being almost entirely solid or it having an ocean deep enough to drown entire planets. While the people who discovered it offer a couple of theories for its formation, neither is especially likely.
A freakish outlier
The study of the new planet started as many now do: It was identified as an object of interest by the Transiting Exoplanet Survey Satellite (TOI, for TESS Object of Interest). TOI-1853 is a star somewhat smaller than our Sun, with about 0.8 times its mass. And there were clear indications of a planet orbiting the star, called TOI-1853 b. The planet orbits quite close to its host star, completing a full orbit in 1.24 days.
The researchers used that orbit time to determine the distance the planet orbits. Based on a combination of that distance, the size of the star, and the amount of light blocked by the planet, it's possible to estimate the planet's size. That turned out to be about 3.5 times Earth's radius, meaning it's a bit smaller than Neptune.
On its own, that's not unusual; many Neptune-sized planets have been discovered. But the combination of size and proximity to the star is unexpected. It places it in what's called the "hot Neptune desert," where intense radiation from the star drives off a planet's atmosphere. Neptunes that reach the hot desert state end up stripped down to their rocky cores, which leaves them as super-Earths.
So what was TOI-1853 b doing in the desert? To find out, the researchers used ground-based observatories to track the movement of its host star as the gravitational pull of TOI-1853 b shifted as it moved through its orbit. The acceleration in the star's motion due to this pull can be used to estimate the planet's mass.
It turned out that TOI-1853 b has a lot of mass. It's estimated to be 73 times the mass of Earth or over four times the mass of Neptune. Pretty clearly, that means its composition must be very different from Neptune's.
Crunchy on the inside and outside?
The researchers involved in its discovery spend a fair bit of text describing just how much of an outlier this makes TOI-1853 b. There are planets with similar densities, but they're typically significantly smaller—the super-Earths formed by stripping away the atmosphere on a Neptune-like planet. There are planets with similar masses, but they're almost all twice as large and are likely to have extensive atmospheres and/or oceans. "It occupies a region of the mass–orbital [distance] space of hot planets that was previously devoid of objects, corresponding to the driest area of the hot-Neptune desert," the researchers conclude. | Chemistry and Material Sciences |
In the 1980s, geophysicists made a startling discovery: two continent-sized blobs of unusual material were found deep near the center of the Earth, one beneath the African continent and one beneath the Pacific Ocean. Each blob is twice the size of the Moon and likely composed of different proportions of elements than the mantle surrounding it.
Where did these strange blobs -- formally known as large low-velocity provinces (LLVPs) -- come from? A new study led by Caltech researchers suggests that they are remnants of an ancient planet that violently collided with Earth billions of years ago in the same giant impact that created our Moon.
The study, published in the journal Nature on November 1, also proposes an answer to another planetary science mystery. Researchers have long hypothesized that the Moon was created in the aftermath of a giant impact between Earth and a smaller planet dubbed Theia, but no trace of Theia has ever been found in the asteroid belt or in meteorites. This new study suggests that most of Theia was absorbed into the young Earth, forming the LLVPs, while residual debris from the impact coalesced into the Moon.
The research was led by Qian Yuan, O.K. Earl Postdoctoral Scholar Research Associate in the laboratories of both Paul Asimow (MS '93, PhD '97), the Eleanor and John R. McMillan Professor of Geology and Geochemistry; and Michael Gurnis, the John E. And Hazel S. Smits Professor of Geophysics and Clarence R. Allen Leadership Chair, director of Caltech's Seismological Laboratory, and director of the Schmidt Academy for Software Engineering at Caltech.
Scientists first discovered the LLVPs by measuring seismic waves traveling through the earth. Seismic waves travel at different speeds through different materials, and in the 1980s, the first hints emerged of large-scale three-dimensional variations deep within the structure of Earth. In the deepest mantle, the seismic wave pattern is dominated by the signatures of two large structures near the Earth's core that researchers believe possess an unusually high level of iron. This high iron content means the regions are denser than their surroundings, causing seismic waves passing through them to slow down and leading to the name "large low velocity provinces."
Yuan, a geophysicist by training, was attending a seminar about planet formation given by Mikhail Zolotov, a professor at Arizona State University, in 2019. Zolotov presented the giant-impact hypothesis, while Qian noted that the Moon is relatively rich in iron. Zolotov added that no trace had been found of the impactor that must have collided with the Earth.
"Right after Mikhail had said that no one knows where the impactor is now, I had a 'eureka moment' and realized that the iron-rich impactor could have transformed into mantle blobs," says Yuan.
Yuan worked with multidisciplinary collaborators to model different scenarios for Theia's chemical composition and its impact with Earth. The simulations confirmed that the physics of the collision could have led to the formation of both the LLVPs and the Moon. Some of Theia's mantle could have become incorporated into the Earth's own, where it ultimately clumped and crystallized together to form the two distinct blobs detectable today at Earth's core-mantle boundary today; other debris from the collision mixed together to form the Moon.
Given such a violent impact, why did Theia's material clump into the two distinct blobs instead of mixing together with the rest of the forming planet? The researchers' simulations showed that much of the energy delivered by Theia's impact remained in the upper half of the mantle, leaving Earth's lower mantle cooler than estimated by earlier, lower-resolution impact models. Because the lower mantle was not totally melted by the impact, the blobs of iron-rich material from Theia stayed largely intact as they sifted down to the base of the mantle, like the colored masses of paraffin wax in a turned-off lava lamp. Had the lower mantle been hotter (that is, if it had received more energy from the impact), it would have mixed more thoroughly with the iron-rich material, like the colors in a stirred pot of paints.
The next steps are to examine how the early presence of Theia's heterogeneous material deep within the earth might have influenced our planet's interior processes, such as plate tectonics.
"A logical consequence of the idea that the LLVPs are remnants of Theia is that they are very ancient," Asimow says. "It makes sense, therefore, to investigate next what consequences they had for Earth's earliest evolution, such as the onset of subduction before conditions were suitable for modern-style plate tectonics, the formation of the first continents, and the origin of the very oldest surviving terrestrial minerals."
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Earth is unique in the solar system for a number of reasons: It's the only planet with a breathable oxygen atmosphere, it's covered in liquid water and it's the only celestial body (that we know of) to harbor life. An often-overlooked characteristic that makes our planet special, however, is that it's the only rocky body in the inner solar system with strong magnetic poles — your compass would be useless on Mars.
But where do these poles come from, and what do they do? To answer these questions, let's start with a journey to the center of our planet.
Earth's core is separated into two layers: the solid inner core and the molten metal outer core. Both layers are made of a cocktail of magnetic iron and nickel, with a few dashes of lighter elements, such as oxygen, silicon and sulfur.
The inner core is extremely dense and hot, like a giant incandescent marble. But the outer core is fluid, and it swirls around this solid mass with its own convective current. It's this constant convection that generates Earth's magnetic field, John Tarduno, a geophysicist at the University of Rochester in New York, told Live Science.
As heat from the inner core continuously radiates into the outer core, it meets material cooled by plate tectonic activity. This cycle drives convection, giving rise to the so-called geodynamo that produces the magnetic field.
Other planets, like Mars and Venus, don't have magnetic fields, in part because they lack plate tectonics. Evidence suggests that these planets may have once had self-sustaining geodynamos but that they petered out for unknown reasons. Mercury does have a weak magnetic field, but it is only 1.1% as strong as Earth's and doesn't do much to shield the planet from solar radiation.
As the liquid metal in Earth's outer core flows, its motion and high iron content cause the planet to act like a huge dipolar magnet, with one negatively charged pole and one positively charged pole. Around 80% of Earth's magnetic field is organized this way, but the remaining 20% is non-dipolar; rather than forming parallel bands of magnetic force, there are certain regions where the field swirls and eddies, behaving "like weather patterns that kind of float around," Tarduno said.
These irregular patterns produce weird patches in the magnetic field — places like the South Atlantic Anomaly, a large swath of the Atlantic Ocean where the intensity of Earth's magnetosphere dips dramatically. Researchers think this "dent" in the magnetic field arises from unusual tectonic activity underneath Africa. Areas like the South Atlantic Anomaly are fascinating, but they are also concerning, for a couple of reasons.
"The magnetosphere is like a protective envelope," Joshua Feinberg, a geologist who specializes in paleomagnetism at the University of Minnesota, told Live Science. It helps to deflect huge amounts of dangerous solar radiation away from Earth, acting like a planetwide layer of sunscreen. In areas where the magnetosphere is weak, extra doses of radiation leak through, potentially contributing to higher rates of skin cancer.
"Another concern is the effect on satellites," Tarduno said. Bursts of radiation from the sun called coronal mass ejections can knock out satellites and other spacecraft if they aren't shielded by Earth's magnetic field. This can have catastrophic effects for telecommunications, internet access and GPS services in anomaly-impacted areas.
The South Atlantic Anomaly may be 11 million years old, according to a 2020 paper published in the journal PNAS, and it might be connected to another planetary magnetic-field phenomenon: pole reversal.
The history of Earth's magnetic field is written in ancient lava flows and deep-sea sediments. These types of rocky material are rich in magnetic metal fragments, such as tiny chips of iron, which orient themselves along magnetic-field lines. "Eventually, that original alignment gets locked into the sediments, and we get these deep-time records of how the Earth's magnetic field was oriented," Feinberg said.
From these records, scientists know that our planet's magnetic poles drift over time. Currently, the geographic North Pole is about 310 miles (500 kilometers) away from its corresponding magnetic pole (which is technically magnetic south, at the moment). And roughly every 300,000 years, the poles suddenly flip, reversing magnetic north and south, according to NASA.
However, the paleogeomagnetic record shows that a complete pole reversal hasn't happened in about 780,000 years. Some researchers believe this means that we're due for a flip — and that the strength of the South Atlantic Anomaly could indicate that one is close.
If the poles were to reverse, Earth's magnetic field would dip to 20% strength, possibly for centuries. Such an event would plunge our current global communications system into disarray. However, other studies suggest that a flip is not imminent.
Either way, Feinberg said, studying our planet's interior and the paleogeomagnetic record will help us understand the complex interplay between the magnetosphere and life on Earth — and possibly help us prepare for future change.
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Joanna Thompson is a science journalist and runner based in New York. She holds a B.S. in Zoology and a B.A. in Creative Writing from North Carolina State University, as well as a Master's in Science Journalism from NYU's Science, Health and Environmental Reporting Program. Find more of her work in Scientific American, The Daily Beast, Atlas Obscura or Audubon Magazine. | Chemistry and Material Sciences |
Buried ice will be a vital resource for the first people to set foot on Mars, serving as drinking water and a key ingredient for rocket fuel. But it would also be a major scientific target: Astronauts or robots could one day drill ice cores much as scientists do on Earth, uncovering the climate history of Mars and exploring potential habitats (past or present) for microbial life.
The need to look for subsurface ice arises because liquid water isn’t stable on the Martian surface: The atmosphere is so thin that water immediately vaporizes. There’s plenty of ice at the Martian poles – mostly made of water, although carbon dioxide, or dry ice, can be found as well – but those regions are too cold for astronauts (or robots) to survive for long.
Led by the Planetary Science Institute in Tucson, Arizona, and managed by NASA’s Jet Propulsion Laboratory in Southern California, SWIM pulls together data from several NASA missions, including the Mars Reconnaissance Orbiter (MRO), 2001 Mars Odyssey, and the now-inactive Mars Global Surveyor. Using a mix of data sets, scientists have identified the likeliest places to find Martian ice that could be accessed from the surface by future missions.
Instruments on these spacecraft have detected what look like masses of subsurface frozen water along Mars’ mid-latitudes. The northern mid-latitudes are especially attractive because they have a thicker atmosphere than most other regions on the planet, making it easier to slow a descending spacecraft. The ideal astronaut landing sites would be a sweet spot at the southernmost edge of this region – far enough north for ice to be present but close enough to the equator to ensure the warmest possible temperatures for astronauts in an icy region.
“If you send humans to Mars, you want to get them as close to the equator as you can,” said Sydney Do, JPL’s SWIM project manager. “The less energy you have to expend on keeping astronauts and their supporting equipment warm, the more you have for other things they’ll need.”
Building a Better Map
Previous iterations of the map relied on lower-resolution imagers, radar, thermal mappers, and spectrometers, all of which can hint at buried ice but can’t outright confirm its presence or quantity. For this latest SWIM map, scientists relied on two higher-resolution cameras aboard MRO. Context Camera data was used to further refine the northern hemisphere maps and, for the first time, HiRISE (High-Resolution Imaging Science Experiment) data was incorporated to provide the most detailed perspective of the ice’s boundary line as close to the equator as possible.
Scientists routinely use HiRISE to study fresh impact craters caused by meteoroids that may have excavated chunks of ice. Most of these craters are no more than 33 feet (10 meters) in diameter, although in 2022 HiRISE captured a 492-foot-wide (150-meter-wide) impact crater that revealed a motherlode of ice that had been hiding beneath the surface.
“These ice-revealing impacts provide a valuable form of ground truth in that they show us locations where the presence of ground ice is unequivocal,” said Gareth Morgan, SWIM’s co-lead at the Planetary Science Institute. “We can then use these locations to test that our mapping methods are sound.”
In addition to ice-exposing impacts, the new map includes sightings by HiRISE of so-called “polygon terrain,” where the seasonal expansion and contraction of subsurface ice causes the ground to form polygonal cracks. Seeing these polygons extending around fresh, ice-filled impact craters is yet another indication that there’s more ice hidden beneath the surface at these locations.
There are other mysteries that scientists can use the map to study, as well.
“The amount of water ice found in locations across the Martian mid-latitudes isn’t uniform; some regions seem to have more than others, and no one really knows why,” said Nathaniel Putzig, SWIM’s other co-lead at the Planetary Science Institute. “The newest SWIM map could lead to new hypotheses for why these variations happen.” He added that it could also help scientists tweak models of how the ancient Martian climate evolved over time, leaving larger amounts of ice deposited in some regions and lesser amounts in others.
SWIM’s scientists hope the project will serve as a foundation for a proposed Mars Ice Mapper mission – an orbiter that would be equipped with a powerful radar custom-designed to search for near-surface ice beyond where HiRISE has confirmed its presence. | Chemistry and Material Sciences |
The idea that one of Britain's oldest cathedrals could help unlock the secrets of life the solar system may sound far-fetched.
But that is exactly what scientists are hoping for after embarking on a project to collect extraterrestrial dust which has fallen on ancient roofs from space.
It is hoped that these particles, which come from comets and meteorites, may hold clues to how life formed on Earth.
A team of experts drew up a list of 13 cathedrals they believe may be ideal locations to recover samples of micrometeorites, beginning with Canterbury Cathedral.
Some of the researchers from the University of Kent have now climbed to the top of the 1,000-year-old building to search for the particles, which are usually only found in places like Antarctica because ordinary terrestrial dust makes them hard to detect.
Cathedral roofs, however, are ideal spots to find cosmic dust because of their size and inaccessibility.
Dr Penny Wozniakiewicz, a senior lecturer in Space Science at the University of Kent, said: 'Up until recently, it was generally regarded that trying to search for micrometeorites anywhere other than places like the Antarctic - where we have a really low background level of terrestrial dust - would be very difficult.
'They are arriving on Earth in large numbers, so we estimate that around 20,000 to 40,000 tonnes of extraterrestrial dust is arriving every year.
'But that's spread over the whole surface of the planet.'
She added: 'There have been estimates that it amounts to about one to six particles per metre square per year arriving if you spread it equally.
'If you're lucky, one might hit you - but not hard. By the time they reach the surface, they are floating down.
'But in places other than the Antarctic you've obviously got large amounts of terrestrial dust that we're making, and this can get very difficult to search through for cosmic dust.'
Dr Matthias van Ginneken, a research associate at the University of Kent, said: 'Micrometeorites are the particles that survive atmospheric entry.
'Most of it gets burnt up when reaching the atmosphere because of collisions with air molecules; they become what we call meteoric smoke.
'But micrometeorites are between a few tens of microns in size up to, let's say, two millimetres.
'So the very big ones you can see with your naked eye like you can see a black dot on your finger.'
Once the samples have been collected, the researchers take them back to the lab in an attempt to isolate the cosmic dust from other matter found on the roof.
Dr van Ginneken added: 'You take it back to the laboratory and wash the sample because roofs are pretty dirty. There's a lot of bird poo, for example.
'Then, once it's clean, you can use a microscope and then spend hours and hours just looking for spheres.
Dr Wozniakiewicz said scientists often use magnets to help collect micrometeorites.
'A really cool characteristic of a lot of extraterrestrial dust is that they contain magnetic material within them,' she added.
'So you can increase your chances of finding a micrometeorite by using a magnet to actually separate out the magnetic portion and then search through that.
'Then, if you look for the particles that have actually come through the atmosphere and melted, they'll form very distinctive spheres, very beautiful spheres.
'In short, you can indeed find cosmic particles amongst the dust on rooftops.'
Dr van Ginneken said the aim of the project was to find clues about how life formed on Earth.
'To make it very simple, let's say that we know amino acids are the building blocks of life,' he said.
'They're rather simple organic molecules; carbon-based molecules that are necessary for life to appear.
'These molecules were found on meteorites, and micrometeorites as well.
'So there is a possibility that the building blocks of life didn't appear on Earth but appeared in space, then were delivered to early Earth.
'And then the presence of water and energy allow these molecules to get more and more complex - eventually leading to the operation of life.'
The team of researchers have also secured permission from several other cathedrals across the country to carry out similar rooftop investigations.
Canterbury Cathedral was originally founded in 597 but was later rebuilt between 1070 and 1077, enlarged at the close of the 12th century and again rebuilt in the Gothic style following a fire in 1174.
The cathedral became a popular pilgrimage site because of its shrine of Thomas Becket - the archbishop who was murdered there in 1170. | Chemistry and Material Sciences |
Two new studies associated with the James Webb Space Telescope’s Early Release Science program have been published, and both have to do with Jupiter’s moons, namely Ganymede and Io.
The first study, led by astronomer Samantha Trumbo from Cornell University and published in Science Advances, presents a fascinating first—the unprecedented detection of hydrogen peroxide on Ganymede. The second study, published in JGR: Planets, reveals another neat finding—sulfurous fumes, specifically sulfur monoxide, on Io.
Both discoveries are linked by a rather powerful force: Jupiter’s immense influence on its natural satellites. And both studies were made possible by astronomy’s new superstar—the James Webb Space Telescope (JWST).
“This shows that we can do incredible science with the [JWST] on solar system objects, even if the object is really very bright, like Jupiter, but also when you look at very faint things next to Jupiter,” Imke de Pater, an astronomer at the University of California-Berkeley, explained in a press release.
For the Ganymede survey, the team used Webb’s near-infrared spectrometer (NIRSpec) to see how light was absorbed by hydrogen peroxide (H2O2) near the moon’s polar regions. The presence of this chemical, which we use on Earth as a disinfectant and bleaching agent, results from the interaction between charged particles around Jupiter and Ganymede, and the ice covering the moon.
Webb telescope “revealing the presence of hydrogen peroxide at Ganymede’s poles shows for the first time that charged particles funneled along Ganymede’s magnetic field are preferentially altering the surface chemistry of its polar caps,” said Trumbo. As a relevant aside, Ganymede is the only moon in the solar system known to host its own magnetic field.
The team argues that radiolysis—the process whereby radiation breaks down molecules—is behind hydrogen peroxide production on Ganymede. “Just like how Earth’s magnetic field directs charged particles from the sun to the highest latitudes, causing the aurora, Ganymede’s magnetic field does the same thing to charged particles from Jupiter’s magnetosphere,” Trumbo added. “Not only do these particles result in aurorae at Ganymede, as well, but they also impact the icy surface.”
Hydrogen peroxide has also been detected on Europa, another Jovian moon, and it’s observed over a large part of the moon’s surface. This is partly because Europa doesn’t have a magnetic field, which would normally protect the surface from incoming, fast-moving particles.
The second study details Webb’s observations of Io, which revealed the presence of multiple ongoing eruptions on the volcanic moon. This included a brightening at Loki Patera—a volcanic complex—and a very bright eruption at the volcano Kanehekili Fluctus. Volcanic activity on Io is the result of enormously strong gravitational forces exerted by Jupiter, which creates tidal heating inside the blistered moon. Of significance, the team, which included de Pater, linked a volcanic eruption to the gas sulfur monoxide (SO), specifically the eruption at Kanehekili Fluctus.
“This is the first time this emission has been seen above an active volcano, and suggests that such emissions are produced by [sulfur monoxide] molecules immediately upon leaving the vent,” the scientists write in the paper. The observation was made on November 15, 2022, when Io was in the shadow of Jupiter, thus preventing Jupiter’s reflected light from overpowering Io’s own light.
Io’s atmosphere mainly consists of sulfur dioxide (SO2), a product of melting sulfur dioxide ice and volcanic eruptions. These volcanoes also produce sulfur monoxide, which is difficult to detect. When in Jupiter’s shadow, however, the sulfur dioxide in Io’s atmosphere freezes onto the surface, leaving behind sulfur monoxide and newly emitted volcanic sulfur dioxide gas. Beneficially, the glowing sulfur monoxide becomes visible when cast within Jupiter’s shadow.
De Pater previously observed Io using the Keck Telescope in Hawaii and discovered low levels of SO emissions across the moon, but couldn’t link them to any active volcano. She suspects these emissions, along with the SO2 observed during an eclipse, come from hidden volcanoes that release gas but no visible dust. Two decades ago, De Pater’s team suggested that the rare state of SO emissions could only occur in hot volcanic vents and last long enough in a sparse atmosphere to emit a specific light wavelength, similar to how Earth’s auroras are produced.
“The link between SO and volcanoes ties in with a hypothesis we had in 2002 to explain how we could see SO emission at all,” de Pater explained. “The only way we could explain this emission is if the SO is excited in the volcanic vent at a temperature of 1,500 Kelvin [ 2,240 degrees Fahrenheit] or so, and that it comes out in this excited state, loses its photon within a few seconds, and that is the emission we see. So these observations are the first that actually show that this is the most likely mechanism of why we see that SO.”
De Pater noted that Loki Patera’s brightening aligned with its eruption cycle, in which it brightens roughly every 500 Earth days for a few months.
Webb continues to astound, whether it’s by making discoveries millions of light years away, or just a few million miles from home. | Chemistry and Material Sciences |
Study reveals violent material ejection process of a dying massive star
A research team led by Dr. Zhang Jujia from Yunnan Observatories of the Chinese Academy of Sciences and Prof. Wang Xiaofeng from Tsinghua University has revealed the stellar mass violently ejected from a progenitor at the end of its life by observing the once-in-a-decade supernova SN 2023ixf. Such mass loss processes can provide essential information for understanding the final evolution of a massive star.
The study was published in Science Bulletin on Sept. 14.
Type II supernovae (SNe II) are the most common stellar explosions in the universe, for which the final stage of evolution of their hydrogen-rich massive progenitors towards core-collapse explosion is elusive. The final stage evolution and the resultant circumstellar environments have led to a rich diversity of such explosions.
To establish a link between the explosion of SNe II and the late-time evolution of massive stars, it is necessary to capture the first-light signals of the SN explosions, i.e., the flashed spectra, due to the ionization of the circumstellar material (CSM)/stellar wind by ultraviolet/high energy photons from shock breakout cooling.
The recent explosion of SN 2023ixf in a very nearby galaxy, Messier 101, provides a rare opportunity to address this long-standing issue. Timely, high-cadence flash spectra taken within one to five days of the explosion allow researchers to place stringent constraints on the properties of the surrounding circumstellar material surrounding this supernova.
It is estimated that the progenitor of SN 2023ixf lost material at a mass-loss rate of 6 × 10-4 M⊙ yr-1 during the last two to three years before the explosion. The nearby material, moving at a velocity of 55 km s-1, accumulated a compact CSM shell within a radius of less than 7 × 1014 cm from the progenitor.
Considering the high mass-loss rate and relatively high wind velocity, together with the pre-explosion observations made about two decades ago, the progenitor of SN 2023ixf could be a short-lived yellow hypergiant that evolved from a red supergiant shortly before the explosion.
"The observation and investigation of SN 2023ixf is ongoing. A series of works on this SN will make it a milestone in the history of SNe II and will then help to reveal the fate of massive stars in the mass range from 10 to 20 M⊙," said Dr. Zhang.
More information: Jujia Zhang et al, Circumstellar material ejected violently by a massive star immediately before its death, Science Bulletin (2023). DOI: 10.1016/j.scib.2023.09.015
Provided by Chinese Academy of Sciences | Chemistry and Material Sciences |
NASA and SpaceX are set to send a spacecraft to a giant metal asteroid discovered back in the 1800s.
The goal? To reveal more about the origins of our solar system.
Here's everything you need to know about the mission.
Psyche is the name of the mission, as well as the name of NASA's spacecraft and the name of the asteroid that it will head to.
The asteroid Psyche is a unique, metal-rich asteroid orbiting the sun between Mars and Jupiter.
It is three times farther from the Sun than Earth - and the distance from Earth to Psyche varies from about 186 million miles to more than 372 million miles.
If all goes as planned, asteroid Psyche's gravity will capture the spacecraft in late July 2029.
The Psyche spacecraft is then expected to spend at least two years orbiting the asteroid - which has a mass of about 440 billion billion pounds - while taking the first-ever images of it.
The purpose of the mission
Unlike most other asteroids that are rocky or icy bodies, scientists think asteroid Psyche is compromised mostly of metallic iron and nickel, similar to Earth's core.
It appears to be the exposed core of an early planet, one of the building blocks of our solar system.
NASA, therefore, hopes to make discoveries about Earth and other rocky planets and how they were formed by looking at Psyche.
The space agency says the asteroid "may offer a close look at the interior of terrestrial planets like Earth".
It adds: "We can't bore a path to Earth's metal core - or the cores of the other rocky planets - so visiting Psyche could provide a one-of-a-kind window into the violent history of collisions and accumulation of matter that created planets like our own.
"If the mission is successful, it will be the first time we've been able to explore a planet formation consisting of iron cores."
NASA says the mission is the exploration of "a new type of world".
The big picture is to learn more about our planet and our universe - but NASA scientists are also curious about the Psyche asteroid itself.
We know it is one of the largest asteroids in our solar system, spanning about 173 miles at its widest point.
The giant metal rock was discovered in 1852 by Italian astronomer Annibale de Gasparis. Because it was the 16th asteroid to be discovered, it is sometimes referred to as 16 Psyche.
NASA said scientists are considering the possibility that Psyche could be an exposed core of an early planet as large as Mars, which shed its rocky outer layers due to violent collisions billions of years ago.
But they are not entirely sure what Psyche is.
It has been viewed through telescopes for nearly two centuries now, yet we don't even know exactly what it looks like.
It has, however, been described as "irregular and potato-like" by NASA.
They also want to know the age of Psyche's surface, as well as its mineral composition and topography.
Scientists have spoken of their excitement about seeing Psyche up close for the first time to learn more about its origin - and one of the most exciting aspects of the mission is "the possibility of the unexpected".
The Psyche spacecraft's main body is about the size of a small van, but with its solar panels, it would just about cover a tennis court.
It is powered by solar electric propulsion and if all goes to plan, the spacecraft will start sending images to Earth in August 2029.
It will use a super-efficient propulsion system called Deep Space Optical Communications (DSOC).
Using a near-infrared laser, DSOC will be the agency's first test of high-bandwidth optical communications between Earth and distances far exceeding the moon.
It means NASA is going from radio communications to laser communications in space, with the space agency comparing it to upgrading old telecommunications infrastructure on Earth with fibreoptics.
This form of communication could potentially provide essential bandwidth enhancement without requiring hardware increases. It should increase data rates 10 to 100 times.
If it proves successful, NASA says the technology will be used by future human and robotic spacecraft to transmit huge volumes of science data, possibly paving the way for NASA to send astronauts to Mars.
When is the launch - and how can I see it?
The launch takes place on Friday 12 October at approximately 3.16pm UK time.
The mission will go into orbit on a SpaceX Falcon Heavy rocket from NASA's Kennedy Space Centre in Florida. | Chemistry and Material Sciences |
A new map of subsurface water on Mars just dropped, and it reveals regions on the Red Planet where ice may be buried beneath the surface for future astronauts to use.
This week, the NASA-funded Subsurface Water Ice Mapping project (SWIM) released its fourth set of maps, which the space agency is calling the “most detailed” since the project first began in 2017.
Using data from several NASA missions, including the Mars Reconnaissance Orbiter (MRO), Mars Odyssey, and the Mars Global Surveyor, SWIM identifies the possible locations of subsurface ice on Mars. For the latest SWIM map, scientists relied on two higher resolution cameras on board MRO, which has been orbiting Mars since 2006 in search of water. As a result, the new map has a much more detailed view of subsurface water than previous iterations which relied on lower-resolution imagers, radar, thermal mappers and spectrometers.
Data from MRO’s Context Camera data was used to further refine the northern hemisphere maps while data from HiRISE (High-Resolution Imaging Science Experiment) was incorporated for the first time to provide the most detailed perspective of the ice’s boundary line as close to the equator as possible, according to NASA. HiRISE even captured a 492-foot-wide (150-meter-wide) impact crater with a “motherlode of ice that had been hiding beneath the surface,” the space agency wrote.
The spacecraft detected what appears to be subsurface frozen water along Mars’ mid-latitudes. This region on Mars is ideal for the landing of future missions as it is characterized by a thicker atmosphere that makes it easier for spacecraft to slow down during their descent to the Martian surface. The real sweet spot for astronauts to land on Mars would be at the southernmost edge of the northern mid-latitudes region, where it’s close enough to the buried ice but also not too far from the equator so that astronauts can enjoy slightly warmer weather.
“If you send humans to Mars, you want to get them as close to the equator as you can,” Sydney Do, SWIM project manager at NASA’s Jet Propulsion Laboratory, said in a statement. “The less energy you have to expend on keeping astronauts and their supporting equipment warm, the more you have for other things they’ll need.”
The Martian poles have plenty of ice, but it’s way too cold over there for astronauts to survive for a long time.
The reason why NASA is more interested in ice found beneath the surface is that any liquid water found on Mars would be unstable. Mars’ atmosphere is so thin that water would immediately evaporate. Subsurface ice, on the other hand, is kept in a safe spot where astronauts can drill ice cores to extract it.
The buried ice will be a valuable resource for future astronauts on Mars who can use it for drinking water or to make rocket fuel. That, in turn, will allow them to carry a lot less to the surface of the Red Planet.
Scientists are also interested to know where the subsurface ice is located on Mars to help them figure out the planet’s climate throughout its history. “The amount of water ice found in locations across the Martian mid-latitudes isn’t uniform; some regions seem to have more than others, and no one really knows why,” Nathaniel Putzig, SWIM’s other co-lead at the Planetary Science Institute, said in a statement. “The newest SWIM map could lead to new hypotheses for why these variations happen.” | Chemistry and Material Sciences |
Astronomers have gotten very good at spotting the signs of planet formation around stars. But for a complete understanding of planet formation, we also need to study examples where planet formation has not yet started. Looking for something and not finding it can be even more difficult than finding it sometimes, but new detailed observations of the young star DG Taurus show that it has a smooth protoplanetary disk without signs of planet formation. This successful non-detection of planet formation may indicate that DG Taurus is on the eve of planet formation.
Planets form in disks of gas and dust, known as protoplanetary disks, around protostars, young stars still in the process of forming. Planet growth is so slow that it's not possible to watch the evolution as it happens, so astronomers observe many protostars at slightly different stages of planet formation to build up a theoretical understanding.
This time an international research team led by Satoshi Ohashi at the National Astronomical Observatory of Japan (NAOJ) used the Atacama Large Millimeter/submillimeter Array (ALMA) to conduct high-resolution observations of a protoplanetary disk around a relatively young protostar, DG Taurus located 410 light-years away in the direction of the constellation Taurus. The team found that DG Taurus has a smooth protoplanetary disk, without any rings which would indicate that planets are forming. This led the team to believe that DG Taurus system will start forming planets in the future.
The team found that in this pre-planet-formation stage, the dust grains within 40 AU (about twice the size of the orbit of Uranus in the Solar System) of the central protostar are still small, while beyond this radius the dust grains have started to grow in size, the first step in planet formation. This is contrary to theoretical expectations that planet formation starts in the inner part of the disk.
These results provide surprising new information about the dust distribution and other conditions at the start of planet formation. Future studies of more examples will further improve our understanding of planet formation.
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Credit: NASA/JPL-Caltech/ASU
I know I was just all hyped about the OSIRIS-REx asteroid mission and believe me, I still am. But now there’s a new asteroid mission on the block and it’s only fair I get all hyped up about that one too. NASA is preparing this coming Thursday, October 12th, to launch Psyche, a spacecraft destined to explore one of the strangest worlds in the asteroid belt, the asteroid…Psyche.
Yes, the spacecraft and the asteroid have the exact same name. Was that a good idea? No. No, it was not. But NASA does not consult me about how to name their spacecraft (otherwise I’d give them a lesson in how acronyms actually work). So just to keep things clear, I’ll be referring to them as Spacecraft Psyche and Asteroid Psyche from here on. I blame NASA.
Anyway, let’s meet this new spacecraft, and find out just why this asteroid is cool!
NASA only gets to build so many missions per year, so when they pick a target to explore you know there must be something special about it, and that definitely holds true for Asteroid Psyche. It is among the largest asteroids in the belt, with its roughly 140-mile diameter putting it 17th in terms of size. That may sound low on the list, but keep in mind the belt contains millions of rocks, so being number 17 puts you pretty high up there.
It may be 17th in terms of size, but it’s only 10th in terms of mass. That’s because Asteroid Psyche’s makeup isn’t quite like any other asteroid—it’s extremely dense. We suspect that a lot of this rock—somewhere between 30-60%--is actually metal, mostly likely iron. As a result it’s classified as an M-type asteroid, a class that contains higher-than-normal concentrations of metal (random nerd side note: as a Star Trek fan, the designation of “Class M” for this asteroid has always delighted me, since Starfleet considers a “Class M” planet to be one that is suitable for humanoid life. That definitely does not apply to Asteroid Psyche, but it pleases me all the same).
Asteroid Psyche sits firmly in the main part of the asteroid belt between Mars and Jupiter, so it’s orbiting the Sun about three times farther away than Earth is. At that distance it takes this metallic rock about five Earth years to complete a single orbit.
As another fun aside, Psyche was discovered early enough (it was the 16th asteroid ever discovered, back in 1852, so its full designation is 16 Psyche) that astronomers were still giving things symbols as well as names. “Psyche” means “soul” in Greek, and apparently the Greek symbol for the soul is a butterfly, so the symbol for Asteroid Psyche is a semi-circle, to represent a butterfly’s wing, crowned by a star, which I find delightfully lovely and whimsical. The semi-circle for the butterfly wing was then incorporated into the patch for Spacecraft Psyche’s mission.
So just how did an object like Asteroid Psyche form? Wonderful question! We don’t know. My personal favorite theory, not necessarily because it’s the most likely but because it’s very definitely the coolest, is that Asteroid Psyche was once the core of something that attempted to become Planet Psyche and failed. In this scenario, extreme impacts stripped the forming outer layers of this theoretical planet away, leaving the core behind. It’s hard to beat the idea of the exposed metallic core of a failed planet. If that’s the case, it would be a chance for us to see what the core of a terrestrial planet would look like with our own eyes (well, with the spacecraft’s anyway). We can’t usually do that because, well, these things are cores, they’re usually on the inside.
There are, of course, other ideas. One is that Asteroid Psyche isn’t a solid object at all, but rather a rubble pile similar to Bennu, the asteroid visited by OSIRIS-REx, although Asteroid Psyche would still be significantly more metallic. A metal rubble pile would be very weird and a very cool find, although I’m still holding out for the exposed planetary core.
Another idea is that Asteroid Psyche is a differentiated object. What that means is that it has different layers made of different materials. Earth, for instance, with its crust and mantle and core, is a differentiated object. We know some of the larger asteroids are, and Asteroid Psyche might be a metal core with a silicate mantle on top of it. In this case Asteroid Psyche might have undergone a sort of volcanism that we haven’t seen evidence of anywhere else: ferrovolcanism, the eruption of molten metal. We’re not expecting to see it actively happening on Asteroid Psyche, but we think it’s possible that this could have happened in its past, and we want to find evidence for it. Eruptions of molten iron isn’t quite as cool as the exposed core theory, but it’s definitely a close second.
The potential worth of this asteroid is another topic that’s often brought up. The idea of asteroid mining is something that humanity has toyed with in the past, since there are certain materials that are much more commonly found in the asteroid belt than on Earth. In theory this could make the process worthwhile, if we can overcome all of the challenges. We don’t actually know how much everything inside Asteroid Psyche is worth, but some estimates put it at $10,000,000,000,000,000,000. That is, for the record, around 100,000x the estimated worth of the entire global economy. You can see why some folks get dollar signs in their eyes when they think of this rock.
For the record, NASA is not going to Asteroid Psyche with an eye towards starting up mining operations. There are currently no plans in NASA’s future for such an endeavor. Asteroid Psyche is simply a world unlike any other, something NASA’s never been able to resist when given the chance.
Okay, so that’s why we want to go. What are we sending? Spacecraft Psyche is a surprisingly small ship for such a big mission. The entire thing is about the size of a tennis court, and most of that is solar panels. Out where Asteroid Psyche lives, Spacecraft Psyche will only be getting around 10% as much solar energy as it would at Earth, so big panels are required to make sure it gets the power it needs, especially since Spacecraft Psyche doesn’t use a traditional propulsion system. Most things we send into space use chemical thrusters to move about, but Spacecraft Psyche will use its solar panels to charge an electrically-powered rocket instead. We’ve never used such a propulsion system past lunar orbit before, so Spacecraft Psyche will be something of a testbed.
The spacecraft itself, the business part of it, is about 10 feet by 8 feet, or a little bigger than a minivan. That’s not a ton of space, but it’s enough to put in four instruments and a communications experiment. Spacecraft Psyche will carry a spectrometer, for figuring out what exactly Asteroid Psyche is made of, a magnetometer to map out the ragged remnants of Asteroid Psyche’s magnetic field, an x-band radio telecommunications system that will help Spacecraft Psyche map Asteroid Psyche’s gravitational field and figure out what its insides look like, and of course a camera so we can all feast our eyes on Asteroid Psyche’s tortured, pitted surface.
It will also carry a laser communication experiment, Deep Space Optical Communications. The hope is that this communications method will increase spacecraft communications efficiency 10-100 times over the usual methods. If we can prove that it works well so far from Earth it could have big implications both for future robotic exploration and for the day we finally get to send humans to Mars.
Spacecraft Psyche may be small, but it is stacked.
Spacecraft Psyche’s path to the launchpad has been anything but smooth. It was originally supposed to launch a year ago, by October 2022. In June 2022, NASA had to announce that the spacecraft was not going to be ready in time. This led to a major review of the mission development process and it was nearly canceled.
In the end it was determined that, with the spacecraft so close to completion, the best thing to do was to pull resources from a different mission, VERITAS, to get Spacecraft Psyche ready to go when the next launch window rolled around in October 2023. VERITAS was a truly amazing mission to Venus that was still in the early phases of development. With the resources lost to Spacecraft Psyche, it remains a question if VERITAS will ever become a reality (I really hope so, this mission is awesome). The rocket carrying Spacecraft Psyche was also originally supposed to carry a smaller, secondary spacecraft, Janus. When Spacecraft Psyche was delayed, Janus lost its chance to fly and has been “shelved”. It is not expected at this time that Janus will ever fly, though one should never say never.
Just when everything seemed set and Spacecraft Psyche would make its October 5, 2023 launch date, trouble struck again. On September 28, NASA announced they were pushing the launch by a week to this coming Thursday, October 12 after discovering that the spacecraft’s thrusters were going to run hotter than expected. For a moment there was the possibility that the thrusters would have to be replaced and that the mission would not make its launch window. Instead it has been determined that the spacecraft can operate by using its thrusters at only 30% of rated thrust and avoid the overheating problem. This aside cost the spacecraft a week of its launch window, and considering the entire window is only 20 days long, ending on October 25, losing a week is no small thing.
Once Spacecraft Psyche actually launches, it has a long journey ahead of it, about 2.2 billion miles all told (spacecraft are rarely able to take a direct trip out to their targets). It will swing past Mars for a gravity assist in 2026, and is expected to reach Asteroid Psyche in August 2029, nearly six years after its launch. Once there, Spacecraft Psyche is expected to spend at least 26 months in orbit around the asteroid, steadily moving into lower and lower orbits to capture all the information it can.
When Spacecraft Psyche’s mission is over, it’s going to simply shut down, remaining forever (or at least for the foreseeable future) as a new, artificial moon of Asteroid Psyche, the body that gave the spacecraft its name and its purpose. There’s something kind of poetic about that.
In the meantime, keep your fingers crossed that Spacecraft Psyche starts its journey on Thursday as currently planned!
Photo Credits:
1. An artist’s illustration of the Psyche spacecraft flying over the asteroid Psyche. Credit: NASA/JPL-Caltech/ASU
2. The mission patch for the Psyche mission to the asteroid Psyche. Credit: NASA/ASU
3. An artist’s illustration of the asteroid 16 Psyche. Credit: Maxar/ASU/NASA/JPL-Caltech/P. Rubin
4. The spacecraft Psyche being constructed in a cleanroom. Credit: NASA/JPL-Caltech
5. An illustration of the Psyche spacecraft’s journey out to the asteroid Psyche. Credit: NASA/ASU | Chemistry and Material Sciences |
Jupiter's moon Europa is one of a handful of worlds in our solar system that could potentially harbor conditions suitable for life. Previous research has shown that beneath its water-ice crust lies a salty ocean of liquid water with a rocky seafloor. However, planetary scientists had not confirmed if that ocean contained the chemicals needed for life, particularly carbon.
Astronomers using data from NASA's James Webb Space Telescope have identified carbon dioxide in a specific region on the icy surface of Europa. Analysis indicates that this carbon likely originated in the subsurface ocean and was not delivered by meteorites or other external sources. Moreover, it was deposited on a geologically recent timescale. This discovery has important implications for the potential habitability of Europa's ocean.
"On Earth, life likes chemical diversity -- the more diversity, the better. We're carbon-based life. Understanding the chemistry of Europa's ocean will help us determine whether it's hostile to life as we know it, or if it might be a good place for life," said Geronimo Villanueva of NASA's Goddard Space Flight Center in Greenbelt, Maryland, lead author of one of two independent papers describing the findings.
"We now think that we have observational evidence that the carbon we see on Europa's surface came from the ocean. That's not a trivial thing. Carbon is a biologically essential element," added Samantha Trumbo of Cornell University in Ithaca, New York, lead author of the second paper analyzing these data.
NASA plans to launch its Europa Clipper spacecraft, which will perform dozens of close flybys of Europa to further investigate whether it could have conditions suitable for life, in October 2024.
A Surface-Ocean Connection
Webb finds that on Europa's surface, carbon dioxide is most abundant in a region called Tara Regio -- a geologically young area of generally resurfaced terrain known as "chaos terrain." The surface ice has been disrupted, and there likely has been an exchange of material between the subsurface ocean and the icy surface.
"Previous observations from the Hubble Space Telescope show evidence for ocean-derived salt in Tara Regio," explained Trumbo. "Now we're seeing that carbon dioxide is heavily concentrated there as well. We think this implies that the carbon probably has its ultimate origin in the internal ocean."
"Scientists are debating how much Europa's ocean connects to its surface. I think that question has been a big driver of Europa exploration," said Villanueva. "This suggests that we may be able to learn some basic things about the ocean's composition even before we drill through the ice to get the full picture."
Both teams identified the carbon dioxide using data from the integral field unit of Webb's Near-Infrared Spectrograph (NIRSpec). This instrument mode provides spectra with a resolution of 200 x 200 miles (320 x 320 kilometers) on the surface of Europa, which has a diameter of 1,944 miles, allowing astronomers to determine where specific chemicals are located.
Carbon dioxide isn't stable on Europa's surface. Therefore, the scientists say it's likely that it was supplied on a geologically recent timescale -- a conclusion bolstered by its concentration in a region of young terrain.
"These observations only took a few minutes of the observatory's time," said Heidi Hammel of the Association of Universities for Research in Astronomy, a Webb interdisciplinary scientist leading Webb's Cycle 1 Guaranteed Time Observations of the solar system. "Even with this short period of time, we were able to do really big science. This work gives a first hint of all the amazing solar system science we'll be able to do with Webb."
Searching for a Plume
Villanueva's team also looked for evidence of a plume of water vapor erupting from Europa's surface. Researchers using NASA's Hubble Space Telescope reported tentative detections of plumes in 2013, 2016, and 2017. However, finding definitive proof has been difficult.
The new Webb data shows no evidence of plume activity, which allowed Villanueva's team to set a strict upper limit on the rate of material potentially being ejected. The team stressed, however, that their non-detection does not rule out a plume.
"There is always a possibility that these plumes are variable and that you can only see them at certain times. All we can say with 100% confidence is that we did not detect a plume at Europa when we made these observations with Webb," said Hammel.
These findings may help inform NASA's Europa Clipper mission, as well as ESA's (European Space Agency's) upcoming Jupiter Icy Moons Explorer (JUICE).
The two papers will be published in Science on Sept. 21.
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But findings from a new paper published in the journal Nature could lead to reanalysis of that data. An international team of researchers discovered the presence of a molten silicate layer overlying Mars’ metallic core—providing new insights into how Mars formed, evolved and became the barren planet it is today.
Published on October 25, 2023, the team’s paper details the use of seismic data to locate and identify a thin layer of molten silicates (rock-forming minerals that make up the crust and mantle of Mars and Earth) lying between the Martian mantle and core. With the discovery of this molten layer, the researchers determined that Mars’ core is both denser and smaller than previous estimates, a conclusion that better aligns with other geophysical data and analysis of Martian meteorites.
Vedran Lekic, a professor of geology at the University of Maryland and co-author of the paper, compared the molten layer to a ‘heating blanket’ covering the Martian core.
“The blanket not only insulates the heat coming from the core and prevents the core from cooling, but also concentrates radioactive elements whose decay generates heat” Lekic said. “And when that happens, the core is likely to be unable to produce the convective motions that would create a magnetic field—which can explain why Mars currently doesn’t have an active magnetic field around it.”
Without a functional protective magnetic field around itself, a terrestrial planet such as Mars would be extremely vulnerable to harsh solar winds and lose all the water on its surface, making it incapable of sustaining life. Lekic added that this difference between Earth and Mars could be attributed to differences in internal structure and the different planetary evolution paths the two planets took.
“The thermal blanketing of Mars’ metallic core by the liquid layer at the base of the mantle implies that external sources are necessary to generate the magnetic field recorded in the Martian crust during the first 500 to 800 million years of its evolution,” said the paper’s lead author Henri Samuel, a scientist with the French National Center for Scientific Research. “These sources could be energetic impacts or core motion generated by gravitational interactions with ancient satellites which have since then disappeared.”
The team’s conclusions support theories that Mars was at one time a molten ocean of magma that later crystallized to produce a layer of silicate melt enriched in iron and radioactive elements at the base of the Martian mantle. The heat emanating from the radioactive elements would then have dramatically altered the thermal evolution and cooling history of the red planet.
“These layers, if widespread, can have pretty big consequences for the rest of the planet,” Lekic said. “Their existence can help tell us whether magnetic fields can be generated and maintained, how planets cool over time, and also how the dynamics of their interiors change over time.”
NASA’s InSight mission officially ended in December 2022 after more than four years of collecting data on Mars, but the analysis of the observations continues. Samuel, Lekic and their co-authors are among the latest researchers to reexamine prior models of Mars using seismology to confirm the planet’s structure and turbulent history.
"This new discovery of a molten layer is just one example of how we continue to learn new things from the completed InSight mission,” Lekic said. “We hope that the information we’ve gathered on planetary evolution using seismic data is paving the way for future missions to celestial bodies like the moon and other planets like Venus.”
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The paper, “Geophysical evidence for an enriched molten silicate layer above Mars’ core,” was published in Nature on October 25, 2023.
This research was supported by NASA (Award Nos. 80NSSC18K1628, 80NSSC19M0216 and 80NSSC18K1680), the National Center for Space Studies and the French National Research Agency (Award Nos. ANR-19-CE31-0008-08 and ANR-18-IDEX-0001), the European Research Council (Award No. 101019965) and the U.K. Space Agency (Award No. ST/W002515/1). This story does not necessarily reflect the views of these organizations.
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Nature
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Article Title
Geophysical evidence for an enriched molten silicate layer above Mars’ core
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25-Oct-2023 | Chemistry and Material Sciences |
Dante Lauretta has waited nearly 20 years to get his hands on pristine specimens from an asteroid, which he says is a key to unlocking answers to mysteries about the origin of life on Earth. On Tuesday, he got his first look at dust grains returned by NASA's OSIRIS-REx mission.
Because they want to be sure, members of the OSIRIS-REx science team will wipe some of the dust from the asteroid sample canister and send it to a laboratory for analysis. But there's little question the dust grains visible immediately after scientists opened the lid to the canister are from asteroid Bennu, where the OSIRIS-REx spacecraft captured rocks during a touch-and-go landing in 2020.
The spacecraft completed its round-trip journey to asteroid Bennu with a near-bullseye landing of its sample return capsule Sunday morning in Utah. The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) mothership released the capsule to plunge into the atmosphere while it fired its thrusters to maneuver on a trajectory to head back into the Solar System for an extended mission to visit another asteroid.
Ground teams quickly retrieved the capsule and shipped it from Utah to NASA's Johnson Space Center in Houston on Monday on a US Air Force cargo plane. It then traveled to a specially built super-clean curation facility at the space center, which is also home to the collection of Moon rocks brought back on NASA's Apollo missions more than 50 years ago.
The sample canister was then placed inside a glovebox to allow scientists to work with the hardware through gloved ports. Then came the moment Tuesday when scientists opened the lid.
“We opened up the canister today, and we did see that there is some black dust-like material that's visible," Lauretta said Tuesday. "We're hoping that's from Bennu. We expect that we'll be collecting a portion of that tomorrow morning, and that'll go right into laboratories."
"This is our first glimpse of what we might have," Lauretta said. "There's good indication that we might have sample."
Tip of the iceberg
When the spacecraft departed the roughly 1,600-foot-wide (500-meter) asteroid Bennu in 2020, engineers estimated the probe had gathered around 250 grams, or 8.8 ounces, of specimens from Bennu's porous surface. The spacecraft sampled the asteroid by extending a robotic arm out in front of it, then essentially pogoing off the surface, only contacting Bennu for a few seconds. When it touched the asteroid, the spacecraft released a burst of gas to funnel loose rocks into a collection chamber shaped like an air filter on the end of the robot arm. This device is called the Touch-and-Go Sample Acquisition Mechanism, or TAGSAM.
Scientists discovered the collection chamber's door was wedged open with larger rocky material, with some fragments of rock leaking out into space, so they decided to quickly stow the sampling device inside the return capsule to avoid losing more material. That led some scientists on the OSIRIS-REx team to wonder whether the spacecraft might come back to Earth with even more than the 250-gram estimate, which was four times the minimum requirement for mission success.
Researchers likely won't know for sure how much material OSIRIS-REx brought home until next month. That will require the lab team in Houston to remove the TAGSAM sampling mechanism from its restraint inside the canister, which protected it for the journey back to Earth like a nested doll. Then they will open up the device and hopefully find larger chunks of rock. All of this should happen in the next couple of weeks.
But the first glimpse at the inside of the sample canister looks promising.
"By Friday, we should have a pretty good sense of what the quick-look analysis is telling us (about the dust)," Lauretta said. "First of all, do we, in fact, have asteroid dust? That's the first thing. Is it the kind of material that we expected, based on the remote sensing that we did at the asteroid? And how does that feed into our sample analysis plan, which we've been writing over the past two years in great detail?
"That's just the dust that we can visibly see right now. The real treasure is inside TAGSAM, which we're not going to get access to until probably late next week, and that is going to be a very deliberative process to figure out what is the nature of that collection, and how do we fairly distribute it to our international partners, to the science team for OSIRIS-REx, and also preserve the long-term integrity for future researchers."
NASA will set aside about 70 percent of the asteroid sample to be analyzed decades in the future by scientists equipped with new lab technology and techniques. NASA has scheduled a press conference for October 11 to reveal more details about the nature of the sample from Bennu.
"I'm thrilled here because this is the moment we've been dreaming of," Lauretta said. "We can see the thing that touched Bennu is now in our laboratories. Of course, we can't wait to get inside. We’ve still got a lot of work to do. We still gotta get inside that TAGSAM. That's where the real treasure is, but we know how to do that and the team is ready and raring to go." | Chemistry and Material Sciences |
NASA'S James Webb Space Telescope observed a planet outside of our galaxy that might be able to support life. Webb discovered the presence of methane and carbon dioxide on the exoplanet K2-18 b, which is 8.6 times the size of Earth. This indicates K2-18 b could be a Hycean exoplanet.
Exoplanets are planets beyond our solar system and Hycean, which comes from a combination of "hydrogen" and "ocean," describes planets that scientists hypothesize have hydrogen-rich atmospheres and liquid-water oceans, according to Space.com.
There was also a possible detection of dimethyl sulfide dimethyl sulfide, known as DMS, on K2-18 b. DMS is a molecule that, when on Earth, is produced by life, according to NASA.
K2-18 b is in the habitable zone, which means its distance from a star may allow water to exist on its surface. These zones are also known as "Goldilocks zones," taking their name from the old children's story because conditions are "just right" for life.
Not only did the planet show an abundance of methane and carbon dioxide, but also a shortage of ammonia. This means an ocean may exist under K2-18 b's hydrogen-rich atmosphere, according to NASA.
The DMS on the planet also leads researchers to believe there could be life on the planet, since DMS in Earth's atmosphere is created by phytoplankton, a marine algae that provides food to sea creatures and is created by sunlight.
"Upcoming Webb observations should be able to confirm if DMS is indeed present in the atmosphere of K2-18 b at significant levels," said Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper on these observations.
Planets like K2-12 b are still "poorly understood," NASA says. However, some astronomers believe they could be a promising place to search for life.
"Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere," Madhusudhan said. "Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations."
The exoplanet's oceans could be too hot to support life. But while K2-18 b has carbon-bearing molecules, it is not yet known if the planet could support life, according to NASA.
There have only been two observations of K2-18 b but there are "many more on the way," said Savvas Constantinou of the University of Cambridge, who worked on the Webb team that observed the exoplanet. "This means our work here is but an early demonstration of what Webb can observe in habitable-zone exoplanets."
for more features. | Chemistry and Material Sciences |
NASA’s Psyche spacecraft has blasted off and begun a six-year, 2.2-billion-mile journey to a peculiar asteroid. Astronomers have speculated that the space rock, also named Psyche, was once the partial core of a small planet in the early days of the Solar System. The seemingly iron- and nickel-rich asteroid may hold clues to the formation of planets, including our own.
On Friday, the uncrewed Psyche spacecraft lifted off at 10:19AM ET aboard a SpaceX Falcon Heavy rocket at Kennedy Space Center in Florida. After successfully jettisoning its fairings and separating from the rocket, ground controllers established two-way communication. Telemetry reports indicate it made it to space in good health. The mission had faced numerous delays before finally lifting off.
Psyche (the asteroid) rotates around the sun in a belt between the orbits of Mars and Jupiter. Researchers estimate it’s made of 30 to 60 percent nickel-iron core, allowing them a rare glimpse into a (possible) planetary core. “My best guess is that it’s more than half metal based on the data that we’ve got,” Lindy Elkins-Tanton, an Arizona State University professor working as the mission’s principal investigator, told The New York Times. “We’re really going to see a kind of new object, which means that a lot of our ideas are going to be proven wrong.”
The spacecraft will take around six years to reach Psyche. At that point, NASA’s Psyche craft will orbit the asteroid for 26 months, studying it with various instruments. The craft will use cameras to get an up-close peek, a magnetometer to look for an ancient magnetic field, a gamma-ray spectrometer to detect high-energy gamma rays and neutrons and a radio antenna to map the space rock’s gravity.
“I am excited to see the treasure trove of science Psyche will unlock as NASA’s first mission to a metal world,” said Nicola Fox, a NASA Science Mission Directorate associate. “By studying asteroid Psyche, we hope to better understand our universe and our place in it, especially regarding the mysterious and impossible-to-reach metal core of our own home planet, Earth.”
The spacecraft will also test NASA’s deep space laser communications, an experimental communications method that could increase deep space bandwidth 100-fold over the current standard, radio waves. “It’s exciting to know that, in a few short weeks, Deep Space Optical Communications will begin sending data back to Earth to test this critical capability for the future of space exploration,” said Dr. Prasun Desai, Associate Administrator (Acting), STMD at NASA HQ. “The insights we learn will help us advance these innovative new technologies and, ultimately, pursue bolder goals in space.” | Chemistry and Material Sciences |
2-faced white dwarf star surprises astronomers
Like other varieties of stars, white dwarf stars are generally pretty similar to each other. Except when they’re not. An international team of astronomers said on July 19, 2023, that they’ve discovered a white dwarf star that’s noticeably different. Oddly enough, it’s two-faced. One half is composed of hydrogen, while the other half is made of helium. Strange, right?
In fact, it’s the first known white dwarf of its kind.
A 2-faced white dwarf star
The astronomers discovered the white dwarf star, nicknamed Janus after the two-faced Roman god of transition, using the Zwicky Transient Facility (ZTF) instrument at Caltech’s Palomar Observatory. The researchers were searching for highly magnetized white dwarfs. That’s when they found Janus. The paper states:
Here we report observations of ZTF J203349.8+322901.1, a transitioning white dwarf with two faces: one side of its atmosphere is dominated by hydrogen and the other one by helium.
Interestingly, Janus experienced rapid changes in brightness. The research team then used the CHIMERA instrument at Palomar, as well as HiPERCAM on the Gran Telescopio Canarias in Spain’s Canary Islands, to investigate further. They also found that Janus rotates on its axis once every 15 minutes.
The surface of the white dwarf completely changes from one side to the other. When I show the observations to people, they are blown away.
Additional observations
Subsequently, the researchers conducted additional observations using the W. M. Keck Observatory on Maunakea in Hawaii. That’s when Janus revealed its double-faced nature. Using a spectrometer, Caiazzo and her colleagues found hydrogen on the side of the white dwarf facing us at the time. But when the other side of the white dwarf rotated into view, it was found to contain helium instead.
Why 2 such different sides?
So what could cause the star to be so different from one side to the other? One possibility, the researchers say, is that the star is undergoing a rare phase of evolution. This phase involves both hydrogen and helium. Caiazzo said:
Not all, but some white dwarfs transition from being hydrogen- to helium-dominated on their surface. We might have possibly caught one such white dwarf in the act.
Hydrogen tends to float to the top of white dwarf atmospheres. Heavier elements, meanwhile, sink to the core. Scientists think all of these elements gradually mix together as the white dwarf cools. It’s also thought that helium may eventually become dominant in some, but all, cases.
However, that still doesn’t quite explain why Janus has two such different sides.
Magnetic fields
The rest of the answer may have to do with magnetic fields. Caiazzo explained:
Magnetic fields around cosmic bodies tend to be asymmetric, or stronger on one side. Magnetic fields can prevent the mixing of materials. So, if the magnetic field is stronger on one side, then that side would have less mixing and thus more hydrogen.
Another possibility is that the magnetic fields change the pressure and density of the atmospheric gases on Janus. Co-author James Fuller at Caltech said:
The magnetic fields may lead to lower gas pressures in the atmosphere, and this may allow a hydrogen ‘ocean’ to form where the magnetic fields are strongest. We don’t know which of these theories are correct, but we can’t think of any other way to explain the asymmetric sides without magnetic fields.
The researchers are hopeful that more white dwarf stars like Janus will be discovered. Since Janus exists, there are likely others as well. Future sky surveys from the Zwicky Transient Facility should be able to find them. As Caiazzo noted,
ZTF is very good at finding strange objects.
What is a white dwarf star?
White dwarfs are called stars, and that is technically true. However, they are actually the dense remaining cores of dead stars. The stars have exhausted their fuel supplies and blasted their gases out into space. They are typically about the size of Earth, but with masses similar to our sun.
And indeed, our own sun will one day become a white dwarf.
Apart from ones that explode in supernovae, most stars eventually become white dwarfs. First, the star inflates enormously to become a red giant. Then, as it evaporates, it leaves behind its stellar core … a new white dwarf.
Bottom line: For the 1st time, astronomers have discovered an unusual white dwarf star where one side is composed of hydrogen and the other side is helium. | Chemistry and Material Sciences |
It is the oldest meteorite ever found, dating back almost 4.6 billion years to a time when the Earth didn't even exist.
Now, space rock Erg Chech 002 is shedding new light on what our early system looked like — and the revelations are not what scientists expected.
A team of Australian researchers say their study brings into question the accuracy of how experts calculate the age of meteorites, suggesting that some may not be as old as first thought.
That's because they found that EC 002 contained more of the radioactive isotope Aluminium-26 (26Al) than other ancient achondrites, or stony meteorites, of a similar age.
This is significant because it challenges the theory that 26AI – which is thought to provide a heat source for the building blocks of planets – was distributed evenly throughout the early solar system.
Experts estimate the age of meteorites based on the amount of 26AI present in them when they were formed.
But if the isotope was distributed unevenly throughout the early solar system, as the new study suggests, then it cannot be relied upon to give an accurate indication of how old a space rock is or what role it might have played in planet formation.
That is at odds with previous research which suggested 26AI was evenly spread in the lead up to the formation of planets such as Earth.
We know that our solar system was formed around 4.5 billion years ago from a collapsing cloud of interstellar gas and dust which was likely part of a much larger nebula.
Scientists think its collapse may have been triggered by the shockwave of a nearby supernova, or exploding star, which in turn led to the creation of a solar nebula — a spinning, swirling disk of material from which the solar system originated.
26AI was then vital in the process that led to us walking on Earth today because it provides enough heat through radioactive decay to produce planetary bodies with layered interiors such as ours.
It also helps dry out early planetesimals to produce water-poor, rocky planets.
Due to its very short half-life of about 770,000 years, scientists think 26AI must have been formed or mixed into the young sun's surrounding planet-forming disk shortly before the condensation of the first solid matter in our solar system.
Its existence in EC 002 therefore provides an opportunity to further explore the initial distribution of the isotope before the Earth was formed.
Whether the isotope was distributed evenly throughout the early solar system is important in determining the age of meteorites.
Researchers at the Australian National University, led by Evgenii Krestianinov, analysed EC 002 and determined its lead-isotopic age to be about 4.566 billion years old.
They combined this finding with existing data for this meteorite and compared it with other very old meteorites that crystallised from melts.
The researchers demonstrated that 26Al had an uneven distribution within the early solar nebula.
For this reason, they said meteorite chronology studies should be cautious and take a generalised approach to dating with short-lived isotopes that account for their uneven distribution.
This, the researchers added, would improve the accuracy and reliability of determining the ages of meteorites and planetary materials.
'Developing a generalised approach for isotopic dating with Al-Mg and other extinct isotope chronometers that accounts for heterogeneous distribution of the parent radionuclide would allow to produce more accurate and reliable age data for meteorites and asteroidal and planetary materials to advance a better understanding for the formation of our solar system,' the authors wrote.
The meteorite was discovered in 2020 in the Erg Chech region of the Sahara Desert in Algeria.
It consists primarily of volcanic rock, leading experts to believe it came from the crust of a very early planet.
A previous study found that the rock was once liquid lava but cooled and solidified over 100,000 years to form the 70-pound piece that eventually made its way to our planet.
No asteroids have been found with similar properties, which suggests the protoplanet it came from has since disappeared by either becoming parts of larger bodies or 'was simply destroyed', the researchers said.
Among the other oldest achondrites previously found include NWA 1111942, which is estimated to be about 4.565 billion years old, and the 4.564 billion-year-old Asuka 88139427.
The new study has been published in the journal Nature Communications. | Chemistry and Material Sciences |
Scientific proof of the existence of intelligent extraterrestrial life could be coming in less than a month, according to a top physicist at Harvard.
Tiny metal fragments recovered from the crash site of a meteor-like UFO that plunged into the Pacific Ocean in 2014 were strong enough to potentially be 'some artificial alloy,' according to Harvard physics professor Avi Loeb.
'There is a chance that it's artificial – that it's a spacecraft,' said Loeb, leader of the recovery efforts to dredge the fragments off the coast of Manus Island this June.
Loeb, who is also the director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, said that the results of this month's analysis could 'definitely' reveal humanity's 'first contact' with aliens.
'I am expecting further news within a month,' Loeb told the Daily Star. 'That's the hope.'
Loeb reports that no less than four research institutions are currently training their scientific equipment and personnel on samples from the recovered metal fragments.
The fragments, 50 mostly iron spheres about 0.1 to 0.7mm in diameter, likely came from an object that originated outside of our solar system — based on analysis by Loeb and a former student as well as scientists with US Space Command.
Loeb's colleagues in Germany, Papua New Guinea and at two top universities in the United States are now busy scrutinizing the spheres to determine if their atomic isotopes, chemical composition and other details can prove an otherworldly origin.
'We are in the process of finding out, within a month or so, what this meteor was made of and whether it is perhaps technological in origin or not,' Loeb said.
Loeb and his colleagues have taken to calling the object IM1, for 'Interstellar Meteor 1,' although it also carries another more technical name with NASA's Center for Near-Earth Object Studies (CNEOS) meteor catalog: CNEOS 20140108.
IM1 is currently ranked first in terms of material strength out of all 273 fireballs in the NASA CNEOS meteor catalog, an early clue to its scientific value.
'It was moving faster than 95 perecnt of the nearby stars near the Sun because of some propulsion it had,' according to Loeb. 'It was also made of some very tough material.'
Loeb has left open the possibility that IM1 — which is estimated to have been about 3 ft. in diameter and approximately half a US ton in weight as it burned through Earth's atmosphere shedding tiny molten metal droplets — might have been an alien probe.
The size of meteor-like object is within the ballpark of humanity's own probes now sailing deeper into the cosmos, like the Voyager 1 and Voyager 2 spacecrafts, which at the longest points of their high-gain antennas come to a length of 12 ft.
The unmanned exploratory probe Voyager 2 is currently itself an interstellar object, now over 12.3 billion miles away from Earth but still beaming its 'heartbeat signal' back to NASA.
'If it's something like the Voyager spacecraft colliding with the planet, that would appear as a meteor,' Loeb noted. 'We will find out.' | Chemistry and Material Sciences |
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