Microbes can survive and grow in 100% hydrogen atmosphere, even though we have very little hydrogen in the Earth’s atmosphere, according to a new study by the Massachusetts Institute of Technology. As a result, the exoplanet environments that may give birth to extraterrestrial life may be more diverse and diverse than previously thought.
High abundance of hydrogen is generally considered beneficial to life, but there is a lack of research on the viability of living things.
Sara Seager, a professor of planetary science at MIT, and colleagues used E. coli and yeast to represent protonuclear and eukaryotic organisms, respectively, and conducted growth experiments in the lab. Although E. coli lives in anaerobic environments such as animal intestines and has been studied in pure nitrogen, it has traditionally not been considered suitable for pure hydrogen.
They exposed the cultured E. coli and yeast to 100% hydrogen and found that they could reproduce normally, but at a slower rate than in the air. Specifically, E. coli is about 2 times slower and yeast is about 2.5 times slower. The authors’ team attributed the slow reproduction to a lack of oxygen.
If microbes such as E. coli do survive on hydrogen-rich planets, they produce gases, some of which can be potential biomarkers, accumulating to a considerable extent and being detected through the atmospheric spectrum.
The paper was published may 4 in Nature Astronomy.
Of course, the actual planetary environment will not be 100% hydrogen, there will always be a mixture of other gases and chemicals, and the team will simply demonstrate in extreme conditions. So is it possible that the atmosphere of exoplanets is dominated by hydrogen? The answer is yes.
If there is a large amount of iron-rich raw material in the planetary disk that gave birth to the planet, it reacts with water during the intense process of the planet’s birth, producing a large amount of gas. To maintain such a hydrogen-rich atmosphere after birth, several conditions need to be met:
It is colder than Earth, has a larger surface gravity than Earth, or has a complementary mechanism to maintain hydrogen content. There is a category of “super-Earths” slightly larger than Earth. And if the surface of the “super subway” is methane ice, it will be converted into ethane, butane and even carbon monocultures at high pressure, releasing hydrogen.
Why is Siegel interested in pure hydrogen? It turns out that the atmosphere of hydrogen-based rocky planets is easier to spot by telescopes than carbon dioxide or nitrogen.
Exoplanets, or exoplanets, were first identified in 1994. So far, scientists have found more than 4,000 exoplanets in the Milky Way alone, mostly the Kepler telescope, which will be decommissioned at the end of 2018. Its successor, the Tess Telescope, went into space in April 2018.
With the first exoplanet discoverer, Swiss astrophysicist Michel Mayor, and his phdall Didier Queloz, who won the Nobel Prize in Physics last year, the field has gone from cold to hot, with research ideas changing, from the broad web to personalized analysis.
In an interview with Newsbeat, Mayor said one of the most exciting research directions in astronomy today is the biomarker, the characteristic spectral information left in the atmosphere when it implies the presence of life on a planet.
The previous generation of telescopes received technical limitations that prevented them from accurately determining the atmospheric details of exoplanets. The European Space Agency plans to launch an atmospheric remote sensing infrared exoplanet survey (ARIEL) around 2028 to analyze the atmospheric composition and evolution of nearly a thousand exoplanets. James Webb, NASA’s next-generation space telescope, could add an “epic” level of space spectrum research to distant planets if launched well.