An artist’s conception shows the light of an alien star shining through a planet’s atmosphere. (NASA Goddard via YouTube)
If we detect oxygen in the atmosphere of an alien world, does that mean life is present? Not necessarily: Scientists say the chemical signature of biological activity is likely to be more subtle, involving a mix of gases that might seem out of whack.
In a paper published today in Science Advances, researchers
Future telescopes will be able to observe atmospheres of distant planets for signs of life. Earth’s oxygen/ozone combination is a sign of life on Earth (top left). For an alien analog to the early Earth (bottom left), the combination of methane and carbon dioxide would provide an alternative biosignature. (UW Illustration / J. Krissansen-Totton via AAAS) …read more