AXIOS - The atmospheres of planets beyond this solar system are coming into focus and helping scientists decide what constitutes evidence of life and where to look for it.
Why it matters: As increasingly sensitive telescopes and other tools study more exoplanets in search of signs of life, scientists are trying to hammer out a framework for determining — and communicating — if and when such extraordinary evidence is found.
"The context is essential because we don't know all of the configurations a purely lifeless planet can take on. We don't know the nature of the most common planet in the universe," says University of California, Riverside astrobiologist Eddie Schwieterman.
"[W]e're only just starting to understand the composition of those atmospheres and there is probably a suite of combinations of gases" that are signatures of life.
"Compelling signs of life on our planet today around another planet may have nothing to do with life," says University of California, Riverside biogeochemistry professor Timothy Lyons.