Researchers have known that Mars used to have water and currently has frozen water, but new information from NASA's Mars Curiosity rover shows that it is possible Mars has liquid water close to its surface.
The substance perchlorate has been found in the soil, which lowers the freezing point so the water does not freeze into ice but is liquid and present in very salty salt water (brine). The results are published in the scientific journal Nature.
In August 2012, Mars Curiosity landed on Mars in the large crater, Gale, south of the Red Planet's equator. In two and a half years, the rover has travelled more than 10 kilometers from the 154-kilometer-in-diameter crater to Mount Sharp - taking samples and performing experiments along the way.
The Mars probe's stereo camera previously found rounded pebbles, like those that would have been made smooth by running water in a riverbed, but new close-up images taken by the rover all the way en route to Mount Sharp show that there are expanses of sedimentary deposits, lying as "plates" one above the other and leaning a bit 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," Bo Madsen said, according to the press release. "When the stream meets the surface, the solid material carried by the stream falls down and is deposited in the lake just at the lakeshore. Gradually, a slightly inclined slope is built up just below the surface of the water and traces of such slanting deposits were found during the entire trip to Mount Sharp. Very fine-grained sediments, which slowly fell down through the water, were deposited right at the very bottom of the crater lake. The sediment plates on the bottom are level, so everything indicates that the entire Gale Crater may have been a large lake."
Bo Madsen said he believes that about 4.5 billion years ago, Mars had about 6.5 times more water than it has now and that the conditions are now too dry for life to be found.
