Can life flourish in hydrogen-rich alien worlds?

US, WASHINGTON (ORDO NEWS) — According to a new study, life can flourish in an atmosphere of 100% hydrogen. A discovery can completely change our understanding of how and where life can exist in the universe.

For research, a team of scientists led by Sarah Seager, an astrophysicist and planetologist at the Massachusetts Institute of Technology (MIT), conducted experiments with the bacteria Escherichia coli or E. Coli, and yeast. They placed these species in a 100% hydrogen atmosphere. And, incredibly, the microbes survived, showing how life can live in such an extreme atmosphere. In comparison, hydrogen makes up less than one millionth of the Earth’s atmosphere, which consists mainly of nitrogen.

“I want to push astronomers to broader thinking about which planets can be inhabited,” Seeger said. “Biologists, if they ever thought about hydrogen-rich atmospheres, would say that it’s normal, because hydrogen is not known to be toxic to life,” she said. However, she noted, astronomers “have no evidence that life can survive in an atmosphere where hydrogen prevails, so our job was to provide clear and concise experimental evidence that this is so.”

Thus, Seager explained, researchers could consider exploring exoplanets or planets outside the solar system, which they would not otherwise consider as potentially possible to sustain life. In addition, since heavy hydrogen atmospheres are usually larger in diameter, it would be easier to detect using some observational methods, she added.

The microbes that Seager and her team studied in the lab grew slower in a 100% hydrogen atmosphere than in a “normal” earth environment, Seager said. She’s several times slower for E. coli and several hundred times slower for yeast, she said. However, she added that “this is not too surprising, because without oxygen, microbes should get all their food from fermentation, and this does not give so much energy.”

Although this experiment showed how life can survive in an atmosphere of pure hydrogen, scientists do not expect to find exoplanets with such an atmosphere. And yet, they hope to find several exoplanets with an atmosphere dominated by hydrogen, Seager said.

“These findings are especially important for finding life, because although we have not found such planets, astronomers believe that there are probably large rocky exoplanets with a thin, hydrogen-rich atmosphere,” Seager said.

“We don’t yet know such planets,” said Seager. “The theory says that they must exist … However, Jupiter, Saturn, Uranus, Neptune, giant exoplanets and mini Neptunes all have atmospheres dominated by H2 [hydrogen] and He [helium] – although no one thinks that life exists there “.

In the future, knowing that life can survive in hydrogen, researchers can expand their observations of distant exoplanets and their atmosphere. They could broaden their eyes to look for planets that they could lose sight of when making observations using existing technologies. In addition, when instruments such as the James Webb Space Telescope (NASA) are launched into space (the space telescope is currently being prepared for launch in March 2021), they will be able to receive even better observations.

This work was published May 4 in the journal Nature Astronomy.


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