Adding to the growing literature on possible life conditions on the Red Planet, new research from NASA's Mars rover Curiosity shows that there may be liquid water close to the surface of Mars.
Experts state that a substance called calcium perchlorate has been found in the soil which lowers the freezing point of water so that it does not freeze into ice, but is liquid and present in the form of very salty water called brine.
"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, head of the Mars Group at the Niels Bohr Institute at University of Copenhagen.
When night falls, some of the water vapour in the atmosphere condenses on the planet surface as frost. But calcium perchlorate, which is very absorbent, forms a brine with the water so that the frost turns into liquid. Based on the measurements of humidity and temperature, scientists can estimate the amount of water that is absorbed.
"Over time, other salts may also dissolve in the soil and now that they are liquid, they can move and precipitate elsewhere under the surface," Madsen said.
New close-up images taken by the rover show that there are expanses of sedimentary deposits, lying as 'plates' one above the other near Mount Sharp on Mars.
"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. But most of this water has disappeared into space, the reason being that Mars no longer has global magnetic fields like we have on Earth. The magnetic field protects the Earth's atmosphere against degradation from energy rich particles from the Sun.
The results from the research were published in the scientific journal 'Nature'.