A recent study suggests that about 4 billion years ago, Mars had underground hydrogen-based energy that could support the development of microbial life. The details of the study are published in the Earth and Planetary Science Letters.
Our planet is home to underground microbial ecosystems, which derive their energy by removing electrons from the molecules in their environment. On our planet – at least underground – these electrons are largely derived from dissolved molecular hydrogen. So the question is: was there at one time this same environment beneath the surface of Mars? Yes, says a study, which estimates that four billion years ago the concentration of hydrogen underneath the Martian surface were equivalent to that that support many microbes on Earth.
“We have shown, from calculations in physics and basic chemistry, that the old Martian subsoil probably had enough dissolved hydrogen to feed a global biosphere,” says Jesse Tarnas of Brown University and lead author of the study. The conditions in this habitable zone would have been similar to those of the Earth where the underground life exists “.
The study does not confirm the past existence of a life on Mars, but that the underground conditions could actually have allowed a microbial life to develop over a few million years. This global underground habitable zone could have even covered several kilometers thick.
This study could thus allow biologists and astronomers to focus the research of a past life on much more precise areas. “One of the most interesting options for exploration is to examine blocks of megabreccia, pieces of rock that have been extracted from the underground by meteorite impacts,” the researcher continues. Many of them could come from the depths of this habitable zone. They would find themselves today on the surface, often relatively unaltered.
And that’s good news. Two of the sites selected by NASA for its next mission March 2020 – Northeast Syrtis Major and Midway – offer this type of underground rock. The rover someday could fall on a “good pick”, revealing to the world the existence of a past extraterrestrial life.