The substance calcium perchlorate found in Mars soil that lowers the freezing point may have left the water under the surface in its liquid form still and may be present in very salty form as a brine, according to researchers.
Perchlorate absorbs water vapor from the atmosphere and lowers the freezing temperature of water, indicating possible existence of transient liquid brines at higher latitudes on modern Mars, despite the Red Planet’s cold and dry conditions, said researchers.
“We have discovered the substance calcium perchlorate in the soil and, under the right conditions, it absorbs water vapour from the atmosphere. Our measurements show that these conditions exist at night and just after sunrise in the winter,” said Morten Bo Madsen of the Niels Bohr Institute at University of Copenhagen.
The Curiosity rover’s near-equatorial location was found to be favorable for small quantities of brine to form during some nights but drying out after sunrise. These conditions should be even more present at higher latitudes, where colder temperatures and more water vapor can result in higher relative humidity, the point out.
“Conditions near the surface of present-day Mars are hardly favorable for microbial life as we know it, but the possibility for liquid brines on Mars has wider implications for habitability and geological water-related processes,” explains Javier Martin-Torres of the Spanish Research Council, Spain, and Lulea University of Technology, Sweden, and a member of Curiosity’s science team.
New close-up images taken by the rover all the way en route to Mount Sharp on Martian soil show that there are vast sedimentary deposits, lying as ‘plates’ one above the other and leaning toward Mount Sharp.
“These kind of deposits are formed when large amounts of water flow down the slopes of the crater and these streams of water meet the stagnant water in the form of a lake,” Madsen said.
Nearly 4.5 billion years ago, Mars had six and a half times as much water as it does now and a thicker atmosphere, say researchers.
But most of this water has disappeared into space as Mars no longer has global magnetic fields as the Earth has, to protect atmosphere against degradation from energy rich particles from the Sun.
The results were published in the scientific journal Nature.