Scientists have discovered compelling evidence that a planet-wide groundwater system once existed on Mars, and that some mineral deposits left by this system suggest it may have contained the essential ingredients for life.
Ancient Martian Ocean Filled Groundwater System
According to a new study, published in Journal of Geophysical Research: Planets this week, the Mars Express Orbiter (MEO) has revealed the first geological evidence for an extensive system of groundwater that once existed on ancient Mars, with some of the mineral deposits left behind by the recession of underground water containing elements thought to be essential for the formation of life.
"Early Mars was a watery world, but as the planet's climate changed this water retreated below the surface to form pools and 'groundwater'," says Francesco Salese, lead author of the paper and a scientist at Utrecht University, the Netherlands.
"We traced this water in our study, as its scale and role is a matter of debate, and we found the first geological evidence of a planet-wide groundwater system on Mars."
In the paper, the researchers describe how they explored 24 several-kilometers-deep, enclosed craters on the surface in Mars’ northern hemisphere and found features in the rock that could only have been formed if water was present.
This includes water channels etched into the walls of the crater, as well as valleys carved by sapping groundwater, and many other features. The water level they discovered syncs up with the theorized shorelines of the primordial ocean thought to have existed on Mars about 3-4 billion years ago.
Signs of Minerals That May Have Produced Life On Earth
Inside five of the craters they studied, the researchers also found evidence of several clays, carbonates, and silicates that are thought to be linked to the emergence of life on Earth.
These sites may be of particular interest to the planners of the ExoMars program, a joint European Space Agency (ESA) and Roscosmos project that will begin hunting for evidence of life that may have existed on Mars at some point in its past.
"Findings like this are hugely important; they help us to identify the regions of Mars that are the most promising for finding signs of past life," says ESA's Mars Express project scientist, Dmitri Titov.
"It is especially exciting that a mission that has been so fruitful at the Red Planet, Mars Express, is now instrumental in helping future missions such as ExoMars explore the planet in a different way. It's a great example of missions working together with great success."