Title: Finding Life on Other Worlds - Science in the News
Headings: Finding Life on Other Worlds
Finding Life on Other Worlds
Finding the Pieces of the Puzzle
Looking in the Neighborhood
Current and Future Missions
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Content: Using this technique, Kepler has identified over 2,400 exoplanets (planets around other stars). The atmosphere of these exoplanets is inferred from spectroscopy, where compounds in the atmosphere block specific wavelengths of light as the planet passes in front of its star. Several of these identified planets are about the size of Earth, and reside in the zone around their star where liquid water could be present based on their stars’ heat output. Looking in the Neighborhood
Due to its proximity, the planet that has been most closely researched for signs of life is Mars, which has been studied using orbiting satellites and rovers, and probably humans themselves in the near future. Though Venus is closer on average to Earth than Mars is, Venus’s 800 degree Fahrenheit acid-laden atmosphere makes it far less likely to sustain life, making Mars our closest plausible planetary neighbor with signs of life. Researchers look for geological features on Mars suggesting the presence of liquid water in its past or present, such as dried-up river basins or underground water, and complex organic molecules that can only be formed by life. So far, small streams of salty water have been observed running down Martian slopes, but the vast majority of water on Mars appears to be in the form of ice. Three other sites in the solar system considered candidates for life are Europa (a moon of Jupiter), and two moons of Saturn: Enceladus and Titan. There is widespread scientific consensus of an ocean of salt water on Europa, hidden by a thick layer of ice.