Laboratory studies reveal microbes can live in extremely hostile environments such as 100 per cent hydrogen.
This finding has implications in the search for extraterrestrial life and expands the amount of planets in which life could thrive to include those previously disregarded.
Many planets have been found with an atmosphere made almost entirely of hydrogen, but they have been previously ignored in the search for life.
Experts now say these worlds should be scrutinised in detail to see if they harbour lifeforms.
Hydrogen also helps keep a planet warm, which makes even more worlds possible hidden sources of alien life, completely unbeknown to us on Earth.
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Many planets have been found with an atmosphere made almost entirely of hydrogen, but they have been widely disregarded in the search for life. Experts now say these worlds should be scrutinised in detail to see if they could harbour some forms of life (stock)
Professor Sara Seager from the Massachusetts Institute of Technology (MIT) believes astronomers should broaden their horizons as they scan the cosmos for life.
She said: ‘Microbes can survive and grow in a 100 percent hydrogen atmosphere. We should expand the types of planets we consider worth searching.’
The award winning astrophysicist, 48, led research published today in Nature Astronomy which found E.coli and yeast survived and grew in pure hydrogen.
The microbes were also able to reproduce in their normal way, just at a much slower rate than in the fertile conditions seen on Earth.
Organisms produced progeny around 300 times slower than in optimum conditions.
Hydrogen in an atmosphere greatly warms the world. On Earth for example, there is only a tiny amount of hydrogen in the atmosphere, keeping conditions temperate despite its relative proximity to the sun.
But the findings show worlds ten times more distant from a star than Earth would be capable of harbouring life as the hydrogen would warm it up.
It means large rocky worlds far from a star could have liquid water – and be habitable – while being subjected to less radiation from their stars.
It makes so-called ‘super-Earths’ — planets similar to our own but up to ten times bigger —prime candidates for life.
They tend to be hydrogen rich and are simpler to spot than their smaller cousins.
They are also dotted all over the Milky Way and it is easy to characterise climactic conditions on these worlds.
Professor Seager said: ‘Life could thrive in a much broader variety of environments than is usually considered.
‘Rocky exoplanets more massive than Earth can retain a significant amount of hydrogen in their atmosphere.
‘Such hydrogen-rich atmospheres are likely to be more extended than Earth-like ones – making them easier to detect.’
Bacteria were also seen to release ‘biosignature’ chemicals, such as nitrous oxide, ammonia and sulfide, that could be used as identifiable markers in future telescopes.
Laboratory studies reveal microbes can live in hostile environments such as 100 per cent hydrogen. This finding has implications in the search for extraterrestrial life, and expands the amount of planets in which life could thrive (stock photo)
Scientists scouring the night sky may be able to specifically look for these chemical signals and hone in on a planet to see if it harbours life.
Professor Seager said: ‘Microorganisms like E. coli produce a great variety of gases – including potential bio-signatures such as nitrous oxide, ammonia and sulfide.
‘These could build up in sizeable abundances – and eventually become detectable.
‘The fact both a simple organism such as E. coli, a prokaryote, and a much more complex one like yeast, a eukaryote, can thrive in a pure hydrogen gas environment and produce a variety of by-product gases, opens the possibility for a much broader spectrum of habitats for life on diverse habitable worlds.
She also explains that it is almost inevitable that there is life beyond Earth, and it may be detected within 15 years.
Professor Seager has said: ‘We stand on a great threshold in the human history of space exploration.
‘If life is prevalent in our neighbourhood of the galaxy, it is within our reach to be the first generation in human history to finally cross this threshold and learn if there is life of any kind beyond Earth.’