Mars may have supported the underground life, but it was a long time ago – BGR

When humanity noticed Mars in the sky, there were surely many people wondering if life was going on its surface. In recent years, we've had a good view of the surface and realized that no one was home, but the old science-fiction cliché of a hidden underground Martian society has remained. Now, a new study reveals that life may have prospered beneath the surface of the planet, but that time has long passed.

The research that was published in Scientific letters of the Earth and planets, suggests that if life on Mars has long been extinct – if it ever existed at first – the underground conditions were once ideal for it to root.

"We have shown, based on physical and chemical calculations, that the old Martian subsoil probably had enough dissolved hydrogen to feed a global underground biosphere," said Jesse Tarnas, lead author of the study. "The conditions in this habitable zone would have been similar to the places on Earth where underground life exists".

The article focuses in part on the hydrogen richness that would have likely been present in Martian soil about four billion years ago, as well as on the existence of surface water . Researchers used climate models and Mars mission readings to estimate the possible magnitude of the subsurface habitable zone. They now believe that a layer as thick as several kilometers would have been ripe for life.

The conditions would have been very similar to those that allow tiny organisms on Earth to flourish. More importantly, even if the sun's rays made life difficult above the ground, they would have been protected under the ground.

Tarnas is quick to point out that this does not necessarily mean that life was present on the old Mars. A planet that is comfortable for life and a planet that actually hosts life are two very different things, and we will have to wait for future Mars missions before we know if traces of past life are present or not.