Astronomy Today@astronomytodayA University of Washington team simulated Earth with all life removed to see which gases can form without biology.
Samantha Gilbert-Janizek's model runs from Earth's formation 4.5 billion years ago to almost half a billion years ahead, and it matches 19 observed traits of pre-industrial Earth, including its oceans and air.
Oxygen and methane together would point to living organisms, while one gas alone proves little. Future telescopes, including the James Webb Space Telescope, could gather the observations needed to compare with the model.
