To the great surprise of physicists and meteorologists alike, NASA's orbiting Fermi gamma-ray observatory has discovered that thunderstorms are emitting powerful bursts of antimatter into space.Antimatter is a mirror image of normal matter with unusual properties — protons with negative charges, electrons with positive charges, and so on. It was created in equal abundance to normal matter at the beginning of the universe, but was destroyed when it came in contact with the normal matter and is now primarily the subject of fiction: the material that powers the starship Enterprise, the bomb beneath the Vatican in the novel "Angels & Demons," and so on.Very small amounts have been produced by powerful particle accelerators including CERN's Large Hadron Collider in Switzerland, but can be captured for only fractions of a second. That's why researchers are so astonished to see antimatter being produced by such a common event as lightning.In retrospect, "we can say, 'Why didn't we realize that was happening?' " said physicist Joseph R. Dwyer of the Florida Institute of Technology in Melbourne , Fla., a coauthor of a paper about the findings that is scheduled to appear in the journal Geophysical Research Letters. Even so, "it's surprising that we are seeing so much…. It illustrates the amazing things that thunderstorms can do."Some indirect evidence in the past suggested that antimatter might be emitted by lightning, added electrical engineer Steven Cummer of Duke University , who studies lightning and the radio emissions from it. "But this is the first time it has been absolutely, unambiguously detected," he said.Fermi, launched in 2008, detects gamma rays, the highest-energy form of electromagnetic waves — a spectrum that includes light rays. When a positron produced by a thunderstorm strikes an electron on the satellite, it releases gamma rays with a characteristic energy of 511,000 electron-volts. Such an event linked to a thunderstorm is known as a terrestrial gamma-ray flash. Fermi has witnessed 130 such events since its launch.Most such events occurred when the satellite was directly over a storm. But one event, on Dec. 14, 2009, occurred when Fermi was over Egypt and the nearest active storm was in Zambia, about 2,800 miles to the south and well below the satellite's horizon.But the spacecraft was connected to the storm by the Earth's magnetic field, Dwyer said. Particles rode up the lines of force and struck the craft. Some went past it and reached what is known as a mirror point,where increasing magnetic-field strength caused the particles to reverse their direction and journey back to strike Fermi 23 milliseconds after the first group.Researchers still have only the roughest of ideas what is happening inside a thunderstorm when lightning is triggered. What is clear is that electric fields build up and accelerate electrons almost to the speed of light, like a giant particle accelerator in the sky, Dwyer said. The electrons "bump into air atoms and make gamma rays, which blast electrons and antielectrons out of the atmosphere."What's interesting, Cummer added, "is if we take what we know is happening and calculate how much antimatter might be produced, it's quite a bit less than what was observed…. So clearly, we don't have a lot of the details."The research was also presented Monday at a Seattle meeting of the American Astronomical Society. ||||| View Images An illustration shows high-energy electrons and positrons from Earth traveling into space. 
 
 Illustration courtesy J. Dwyer/FIT, NASA 
 
 Thunderstorms can shoot beams of antimatter into space—and the beams are so intense they can be spotted by spacecraft thousands of miles away, scientists have announced. 
 
 Most so-called normal matter is made of subatomic particles such as electrons and protons. Antimatter, on the other hand, is made of particles that have the same masses and spins as their counterparts but with opposite charges and magnetic properties. 
 
 Recently, radiation detectors on NASA's Fermi Gamma-ray Space Telescope lighted up for about 30 milliseconds with the distinctive signature of positrons, the antimatter counterparts of electrons. 
 
 Scientists were able to trace the concentrated burst of radiation to a lightning flash over Namibia, at least 3,000 miles (5,000 kilometers) away from the Earth-orbiting telescope, which was passing above Egypt at the time. (See an Africa map.) 
 
 "This is a fundamental new discovery about how our planet works," said Steven Cummer, a lightning researcher from Duke University who was not part of the study team. 
 
 "The idea that any planet has thunderstorms that can create antimatter and launch it into space is something out of science fiction. The fact that our own planet is doing it is truly amazing." 
 
 Intense Antimatter Beam a Shocker 
 
 Scientists already knew that thunderstorms can emit gamma rays—the most energetic form of light—and that gamma rays in turn can create positrons through a process called pair formation. 
 
 When a gamma ray with the right amount of energy interacts with an air atom, energy from the gamma ray is converted into matter, one electron and one positron, lightning expert Joseph Dwyer said yesterday during a meeting of the American Astronomical Society in Seattle, Washington. 
 
 Scientists wouldn't have been surprised to see a few positrons accompanying any intense gamma ray burst, added Dwyer, of the Florida Institute of Technology in Melbourne. 
 
 But the lightning flash detected by Fermi appeared to have produced about 100 trillion positrons: "That's a lot," he said. 
 
 What seems to have happened is that positrons created by the lightning were herded into a tight beam by Earth's magnetic field, said study leader Michael Briggs of the University of Alabama, Huntsville. 
 
 The beam funneled positrons from the Namibian storm to the Fermi spacecraft. 
 
 A few milliseconds after hitting the spacecraft, the beam struck a more northerly section of Earth's magnetic field, Briggs added. This caused some of the positrons to bounce back the way they had come, hitting the spacecraft with a second beam, like an echo. 
 
 Antimatter a Clue to Lightning 
 
 Earth is constantly being bombarded by radiation from the sun, as well as cosmic rays from distant but violent events, such as powerful supernovae. (Also see "Black Holes Belch Universe's Most Energetic Particles.") 
 
 Considering the amount of positrons in the beam Fermi detected, the thunderstorm was briefly creating more radiation—in the form of positrons and gamma rays—than what hits Earth's atmosphere from all other cosmic sources combined, Dwyer noted. 
 
 The researcher has previously said, however, that the danger of thunderstorm radiation to airline travelers is extremely low. 
 
 Duke's Cummer added that nobody knows why some thunderstorms produce gamma rays while most do not. 
 
 "We really don't understand a lot of the details about how lighting works," he said. But discovering the creation of positrons "gives us a very, very important clue as to what's happening."
– Scientists have been amazed to discover that thunderstorms on Earth send bursts of antimatter into space. The phenomenon was spotted by NASA researchers using the Fermi space telescope, the Los Angeles Times reports. Scientists at CERN have only been able to produce antimatter—the mirror image of matter, with the components of its atoms in reverse—in tiny amounts for a fraction of a second. "This is a fundamental new discovery about how our planet works," a lightning researcher tells National Geographic. "The idea that any planet has thunderstorms that can create antimatter and launch it into space is something out of science fiction. The fact that our own planet is doing it is truly amazing."