A new approach to finding alien life proposes that aliens can breathe hydrogen. So it is possible that we will soon discover gases that are linked to terrestrial life in the atmosphere of an exoplanet.
A study published in Nature Astronomy reveals that the best chance to find life using atmospheres is to expand the search further to include planets with hydrogen atmospheres.
Aliens could breathe hydrogen
When studying the atmosphere of an exoplanet , one mainly looks at the amount of light that enters it as it passes by its star.
How much is absorbed and how much is lost in transit is determined by looking at the spectrum of the star. This will reveal gases in the atmosphere, which is why the James Webb Telescope will be used to document extraterrestrial atmospheres .
Interpretations are easier for an atmosphere that has a different chemical composition than expected. This is maintained by the activity of life .
Earth’s atmosphere harbors methane which, when combined with oxygen, forms carbon dioxide. However, biological activities keep the supply of methane high.
Another way of looking at it is that without photosynthetic photoorganisms that release oxygen from carbon dioxide during what is known as the “mass oxygenation event,” oxygen would not exist.
According to the authors of the new study, there are beginning to observe planets larger than Earth with hydrogen atmospheres. They may not have free oxygen, because hydrogen and oxygen are combustible .
Hydrogen is the lightest molecule of all, it can quickly escape into space. A super Earth must have a rocky planet that has enough gravity to support a hydrogen atmosphere. It must also have a mass between 2 and 10 million times that of the Earth.
The hydrogen may have been taken directly from the gas cloud, where the planet formed. Or it could have been released through a chemical process using iron and water.
While ascending, the density of a hydrogen-dominated atmosphere decreases about 14 times faster than a nitrogen-dominated atmosphere. Like on Earth.
A new approach to life
This makes it easier to view spectrum data, increasing the chances of seeing said internal when using an optical telescope.
The authors did laboratory studies to show that E.coli, a bacteria found in the gut, can survive in a hydrogen environment and thrive.
This observation is fascinating, but it does not prove that developed life can survive. Many microorganisms that live under the earth’s crust survive by metabolizing hydrogen . There are even multicellular creatures that live in oxygen-free zones in the Mediterranean soil.
Because Earth’s atmosphere formed without oxygen, it is unlikely that more than 1% hydrogen existed . However, it is possible that early life had to metabolize hydrogen and carbon to generate methane, rather than combining oxygen with carbon.
But this study made a more significant finding; found that E.coli products can give off a “surprising array of gases” when exposed to hydrogen.
These could be detected as ‘biological signatures’ in a hydrogen environment. This increases the chances of detecting life on an exoplanet , but you have to know how to look for it.
But the efficiency of metabolic activities that require hydrogen is lower than those that use oxygen. Astrobiologists say that hydrogen-breathing life is an established idea. In fact, science fiction uses this resource a lot.
The authors of the current study also point to molecular hydrogen as a greenhouse gas in high concentrations. This can keep the planet’s surface warmer than necessary for liquid water, affecting life on the surface.
This study gives us a new approach to search for extraterrestrial life, beyond large gas-rich planets like Jupiter. Therefore, the horizon expands more and more.