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Life can thrive in a 100% hydrogen atmosphere, according to a new study. The finding could completely change our understanding of how (and where) life could exist in the universe.
For the study, a team of researchers led by Sara Seager, an astrophysicist and planetary scientist at the Massachusetts Institute of Technology (MIT), conducted experiments on the bacteria Escherichia colior E. coliand yeast. They put these species in an atmosphere of 100% hydrogen. And, incredibly, the microbes survived, showing how life can live in such an extreme atmosphere. (By contrast, hydrogen makes up less than one part per million terrestrial atmosphere, which consists mainly of nitrogen).
“I want to push astronomers to think more broadly about what kind of planets might be habitable,” Seager told Space.com in an email. “Biologists, if you ever thought of hydrogen-rich atmospheres, you would think that it is okay for life to survive, because hydrogen is not known to be toxic to life,” he said. However, he noted, astronomers “are not aware that life can survive in hydrogen-dominated atmospheres, so our job was to provide clear and concise experimental evidence that this is the case.”
So, Seager explained, researchers could consider studying exoplanets – or planets outside the solar system – that would not otherwise target the search for alien worlds that could potentially support life. Also, because hydrogen-heavy atmospheres are generally larger and more extended from the surface of your planet, they could be easier to detect with some observation techniques, he added.
Studying microbes
The microbes that Seager and his team studied in the laboratory grew more slowly in the 100% hydrogen atmosphere than in a “normal” terrestrial environment, Seager said. “A few times slower for E. coli and a few hundred times slower for yeast, “he said. However, he added,” This is not too surprising, because without oxygen the microbes have to get all their food from fermentation, and that just doesn’t yield as much energy. “
While this experiment showed how life can survive in a pure hydrogen atmosphere, scientists do not expect to find exoplanets with atmospheres made of 100% hydrogen. Still, they hope to find some exoplanets with hydrogen-dominated atmospheres, Seager said.
Staring at the stars
These findings are especially important to the look for life Because, although they haven’t found them yet, astronomers think they are likely large, rocky exoplanets with fine, hydrogen-rich atmospheres, Seager said.
“We don’t know planets like that yet,” said Seager. “Theory says that they should exist … However, Jupiter, Saturn, Uranus, Neptune, giant exoplanets [and] mini Neptunes everyone has H2 [Hydrogen] and the [Helium] dominated atmospheres, although nobody thinks that life is there. “
In the future, knowing that life can survive on hydrogen, researchers could expand their observations of distant exoplanets and their atmospheres. They could widen their gaze to search for those planets that they might otherwise have missed by making observations with existing technology. Also, when tools like NASA’s James Webb Space Telescope launch into space (the space telescope is slated to launch in March 2021), they will be able to get even better observations.
This work was published today (May 4) in the journal Nature Astronomy.
Follow Chelsea Gohd on Twitter @chelsea_gohd. Follow us on twitter @Spacedotcom and in Facebook.
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