A new study claims that the breakdown of water molecules trapped in rocks might have sustained life beneath the surface of ancient Mars.
Scientists believe that there was an ample supply of chemical energy that could have sustained and allowed microbes to thrive underground of the red planet four billion years ago.
The study was published in the journal Earth and Planetary Science Letter.
Life On Mars
"We showed, based on basic physics and chemistry calculations, that the ancient Martian subsurface likely had enough dissolved hydrogen to power a global subsurface biosphere," explained Jesse Tarnas, lead author of the study and a graduate student from Brown University. "Conditions in this habitable zone would have been similar to places on Earth where underground life exists."
The researchers used data from NASA's Mars Odyssey which has been orbiting the red planet since 2001. Through the spacecraft's gamma-ray spectrometer, they inspected the abundances of radioactive elements potassium and thorium to infer abundance of a third radioactive element, uranium, on the planet's crust. This is what the researchers used to provide the radiation that drives radiolysis, the process in which radiation breaks down water molecules into separate hydrogen and oxygen parts.
Thanks to the analysis, the researchers were able to discover that the ancient subsurface of Mars had enough hydrogen for the microbes to survive for hundreds of millions of years. Moreover, the findings held up even when researchers factored in various climate changes that could affect the process. In fact, Tarnas argued, the extreme cold might have helped keep hydrogen from escaping from the subsurface of the planet.
"People have a conception that a cold early Mars climate is bad for life, but what we show is that there's actually more chemical energy for life underground in a cold climate," she added.
Search For Life
Unfortunately, the study does not give confirmation that there was or is life within the subsurface of Mars. However, it showed that life could have existed in the red planet because it had the same key ingredients that allowed life to thrive on Earth billions of years ago.
The study also provides future researchers cues on where to look for evidence of life in ancient Mars. The areas where the ancient subsurface is exposed should be explored.
Jack Mustard, a professor at Brown University and a study co-author, already has his sights on the megabreccia blocks or the chunks of rocks that were excavated due to a meteor strike. He is also involved in the process of choosing a landing site for a rover that will be sent to the red planet in 2020 and revealed that two of the areas being considered have breccia blocks available to be analyzed.