A vast system of canyons that dramatically marks the face of Mars could have harbor hidden water reserves.
An unusually high amount of hydrogen has been detected in the heart of the 4,000 kilometers (2,485 miles) of canyons known as the Valles Marineris, nicknamed the Grand Canyon of Mars. We know this from new data from ESA Roscosmos ExoMars Trace Gas Orbiter FREND instrument.
The discovery suggests that at depths of up to one meter (three feet) below the surface, the region’s soil is rich in water, either bound up-in minerals, or as subsurface water-ice, potentially offering a new way to locate precious things on apparently extremely arid world.
“With trace gas orbiter, we can look-down to a meter under this dusty layer & see what happens below the surface of Mars – and key, to identify water-rich “oases” that cannot be detected with previous instruments, “said physicist Igor Mitrofanov of Space Research Institute of the Russian Academy of Sciences in Russia, lead author of the new study.
“FREND revealed an area with an unusually high amount of hydrogen in the colossal Valles Marineris canyon system: assuming the hydrogen we see is bound in-to water molecules, up to 40% of the nearby material of the surface in this region appears to be water.
We know there is water on Mars. We see it, at the cold poles, tied like ice. This is where most of it seems to be; at the equator, conditions are too warm for water-ice to form at surface.
It is possible that there is water below the surface, but other previous searches by other satellites of Mars has only found it at higher latitudes.
Cue FREND, or Fine Resolution Epithermal Neutron Detector. Rather than mapping the light on the surface of the red planet itself, FREND detects neutrons.
This allows you to see the hydrogen content of Mars soil up to one meter under the surface, said researchers. That in the observations taken between May 2018 & 2021 February seems to have done.
“Neutrons are produced when highly energetic particles known as galactic cosmic rays hit Mars; drier soils emit more neutrons than wetter ones, and we can therefore deduce how much water there is in a soil by observing the neutrons it emits, ”said physicist Alexey Malakhov, also of Space Research Institute of Russian Academy of Sciences .
“We discovered that a central part of Valles Marineris is filled with water, much more water than expected. This is very similar to the permafrost regions of the Earth, where water ice permanently persists under dry soil due to the constant low temperatures.
The high hydrogen region is roughly the size of the Netherlands & overlaps with Candor Chasma, one of the largest canyons in Valles Marineris system. In this region of Mars, minerals typically contain very little water, so researchers believe the substance likely occurs in the form of water ice below the surface.
But how this water can persist there is a mystery. The pressure & temperature conditions at equator of Mars should prevent the formation of such water reserves. There may be an unknown combination of geomorphological conditions at Valles Marineris that allow this, such as isolated patchy deposits that have existed for some time, or the angle & orientation of steep slopes.
Further investigation will be needed to understand exactly what is going on, not only the conditions that allow equatorial water on Mars, but to confirm what form this water takes. This could be very rewarding: Reservoirs of water in the form of like permafrost, as we have discovered here on Earth, may have preserved frozen fragments of microbial life or organic molecules that once existed on Mars.
Discovery also represents exciting possibilities for the exploration of Mars. Any manned mission on Mars is likely to be set-down near the equator; water that could be found not far from the surface would be an extraordinary resource, both for exploration purposes & for the vital task of keeping water dependent humans alive.
And, of course, that makes scientists even more eager to visit the unusual & fascinating Valles Marineris, the largest canyon in our solar system.
“This result really demonstrates the success of joint ESARoscosmos ExoMars program,” said Colin Wilson (physicist), of European Space Agency.
“Learning more about how & where water exists on Mars today is essential to understanding what happened to the once abundant water on Mars and helps us search for habitable environments, possible signs of past life & organic materials from the earliest days of Mars.
The team’s research has been published in Icarus.