Even planets that have very different atmospheres from Earth can host liquid water for long periods of time, a new study suggests. This finding suggested that the concept of planetary habitability should be reconsidered. This is what researchers from the Universities of Bern and Zurich report on Monday in the journal Nature Astronomy.
The team led by doctoral student Marit Mol Lous modeled whether planets with atmospheres of hydrogen and helium can sustain a climate that allows liquid water on the planet’s surface. The atmosphere of the earth initially consisted mainly of these two elements. Over time, it lost this primordial atmosphere in favor of the heavier elements oxygen and nitrogen. However, large rocky exoplanets can maintain such primordial atmospheres.
greenhouse gas effect
As the researchers found out with simulations, the conditions for liquid water could actually prevail on the surface of such exoplanets, provided the atmosphere is thick enough to produce a sufficiently high greenhouse gas effect. If enough geothermal heat reaches the surface, the intense radiation from a star like the sun is not even necessary, Marit Mol Lous was quoted as saying in a broadcast from the University of Bern.