Life on Super-Earths?
Once formed may also be preserved for billions of years: the oceans of Super-Earths and exoplanets are a reality. It is provided by the vehemence of a nearby (too close) red dwarf that does not make the oceans evaporate quickly.
To imagine how life could have formed on other planets, the liquid water is an essential element, a prerequisite to the development of an alien biology. The terrestrial geology suggests that our planet’s large expanses of water have accompanied almost all the history of the Earth system. But does the evidence is also extensible to exoplanets where astronomers look oceans, and especially on those who are known as super-Earths (planets of mass similar to or greater than the planet we inhabit)?
The expanse of an ocean on an exoplanet, in rendering of an artist.
New research suggests that the answer to this question may be yes: once formed, the oceans on other worlds may be preserved for billions of years. Provided that the vehemence of a close, too close, red dwarf does not make them evaporate in less than no time.
“When researchers try to define the end of habitability around a star, it is based primarily on distance and temperature. There should be more focus on large expanses of alien water and find a good destination to go to sail or practice of good surf,” joked Laura Schaefer, first signatory of the article and a researcher at the Harvard-Smithsonian Center for Astrophysics (CfA).
Water covers 70 percent of Earth’s surface, and yet is not that a very small fraction of the mass of the planet. The Earth is primarily rock and iron. “The oceans that cover the Earth are a thin layer as the vapors that are deposited on the mirror of a bathroom during a shower,” says Dimitar Sasselov, co-author of the study and a researcher of the CfA.
But the water on Earth is not only on the surface. The tectonic movements of the Earth’s mantle to the oceans steal large amounts of water that are then expelled again thanks to the phenomenon of volcanism. Just think of the mid-ocean ridges. They are a sort of large recycling system of terrestrial waters.
Schaefer and colleagues have used sophisticated processing computer to see if a similar system can run on planets of greater mass than that of Earth. The results confirm that the Super-Earths between 1.5 and 5 times the mass of our planet can follow the development and maintenance of the oceans in a similar way.
According to data from the planets with a mass of 2-4 times the Earth has, there are also the best conditions for the formation and maintenance of the oceans, and would be able to perfectly preserve it for at least ten billion years. Only the planets with a mass of 5 times greater than the terrestrial mass spend a little longer to cool enough and trigger the process of solidification of the crust. But after about a billion years everything is up to speed.
“If we find life on other worlds is therefore better to focus on Super-Earths older,” concludes Schaefer.