An excerpt from Inside Science
In a new study, researchers investigated how well two different kinds of microbes grew in the lab in 100% hydrogen: the bacterium E. coli, which lacks a nucleus, and yeast, which possesses one.
These microbes can survive and grow in 100% hydrogen atmospheres, suggesting life could potentially evolve on a much broader range of alien worlds than is often considered.
Hydrogen is the most common element in the universe. While astronomers have not yet detected any rocky exoplanets with hydrogen atmospheres, they expect such atmospheres to exist, especially around exoplanets known as super-Earths, which have more mass and therefore stronger gravitational pulls than Earth does.
Since hydrogen is the lightest of all gases, hydrogen atmospheres should prove much puffier than Earth’s, extending so far from the planet’s surface that they should be the easiest rocky exoplanet atmospheres to detect, researchers said.
Scientists found both microbes could reproduce, switching from their preferred oxygen-consuming metabolism to less efficient anaerobic processes. Their growth rates were slower in hydrogen atmospheres, perhaps due to the lack of energy the microbes would normally get from oxygen. E. coli reached numbers roughly half those they would have in regular air, and yeast was hundreds of times less abundant than it would otherwise have been.
The scientists detailed their findings online May 4 in the journal Nature Astronomy.