The Grapevine

Poisonous Earth Gas Could Point To Other Planets That Host Alien Life

A new study funded by NASA’s Astrobiology Institute suggests that a common poisonous gas found on Earth could actually help identify the presence of alien life on other planets outside the solar system. Researchers said the space community should soon look at the buildup of carbon monoxide in a planet's atmosphere to find extraterrestrial life.

A team led by University Of California, Riverside used computer models to explore the composition of the biosphere and atmosphere that may indicate how carbon monoxide form on planets capable of hosting life, EurekAlert first reported.

The models provided the researchers with the idea on how such gas dominated Earth three billion years ago. The ancient Earth appeared capable of maintaining carbon monoxide levels of up to 100 parts per million, a figure significantly higher than the parts-per-billion traces of the gas in the atmosphere today.

"That means we could expect high carbon monoxide abundances in the atmospheres of inhabited but oxygen-poor exoplanets orbiting stars like our own sun," Timothy Lyons, study co-author and a professor of biogeochemistry in UCR's Department of Earth Science, said. "This is a perfect example of our team's mission to use the Earth's past as a guide in the search for life elsewhere in the universe."

The computer models also simulated another scenario showing the buildup of carbon monoxide around red dwarf stars, like Proxima Centauri, that is 4.2 light-years away from the Sun and the nearest of its kind to our solar system.

The researchers said the models suggest that a planet around such red dwarf star could also have extremely abundant carbon monoxide. This means life may potentially be developing on the planet. 

"Given the different astrophysical context for these planets, we should not be surprised to find microbial biospheres promoting high levels of carbon monoxide," Edward Schwieterman, the study's lead author and a NASA Postdoctoral Program fellow in UCR's Department of Earth Sciences, said. 

However, Schwieterman pointed out those planets may not be able to support human or animal life like Earth. He noted that the launch of the James Webb Space Telescope in 2021 will help provide important data that would be useful in analyzing the atmospheres of some rocky exoplanets. 

The researchers published their findings in the Astrophysical Journal