Samantha Gilbert-Janizek

Astronomy Today@astronomytoday

Planetary scientist Samantha Gilbert-Janizek of UC Riverside has built a computer model of a rocky planet evolving without life. It gives astronomers a reference for exoplanet atmospheres.

The model covers 19 properties unrelated to life, such as the heat a planet receives from its star. Run from Earth's birth 4.5 billion years ago through 500 million years ahead, it produced a lifeless world with oceans and an atmosphere.

If a planet's observed atmosphere doesn't match the lifeless simulation, that could hint at life, though it wouldn't prove it, and it could help pick worlds for follow-up.

Astronomy Today@astronomytoday

A 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.