Scientists Find Flowing Salt Water on Mars, Say it’s a Good Place to Look for Life
SCIENTISTS have discovered water flowing on the surface of Mars. (ILLUSTRATION: Mosaic of the Valles Marineris hemisphere of Mars projected into point perspective, a view similar to that which one would see from a spacecraft.)
The discovery announced Monday raises the tantalizing possibility that life could exist today on the red planet, and may turbocharge NASA’s efforts to further explore Mars.
“Mars is not the dry, arid planet we thought of in the past,” said Jim Green, NASA’s chief of planetary science.
Scientists say the water likely exists intermittently as thin layers of wet soil. It is very salty, far more so than oceans on Earth. This brine can therefore exist as a liquid on the surface during the warmer spring and summer months, when temperatures rise to about 0 degrees Fahrenheit.
In the search for life, evidence of flowing water is a game-changer. It strongly indicates that there are large glaciers and possibly flowing water just beneath the surface of Mars.
“It suggests it would be possible for there to be life on Mars today,” said John Grunsfeld, a former astronaut who now leads NASA’s science division.
Until now many scientists believed that while life very well could have existed in the past on a warmer, wetter Mars, the planet is now too cold and dry for life to exist.
During the last four years NASA satellites orbiting the red planet have found curious dark streaks along the sides of mountains and craters. They suspected these features, 5 to 15 feet wide and several football fields long, might be seasonal water flows.
Now, using data collected by NASA’s Mars Reconnaissance Orbiter, scientists led by Georgia Tech University’s Lujendra Ojha have more closely observed these streaks by measuring the kinds of light they absorbed. What they found were salt crystals that contained water molecules. The only reasonable explanation for this is that, periodically, water flows or trickles down these slopes.
A question unanswered for now is what causes these flows. Is water from beneath the surface somehow heated and seeping to the surface or, through a process known as deliquescence, is water from the Martian atmosphere being pulled out of gaseous form and turned into a liquid? NASA won’t be able to answer these questions right away.
Although these dark streaks may exist on Mount Sharp, near where the Mars Curiosity rover landed in 2012, the space agency is concerned that the rover may be contaminated by life it brought from Earth.
Moreover these features often exist on steep inclines, which would be challenging for existing rovers to reach.
Grunsfeld said it would be easy for astronauts, in space suits, to investigate these sites, but a human mission to Mars seems very unlikely before the 2040s.
Another possibility is specially designing a new robotic mission to investigate the dark streaks scattered across the planet. But given funding issues and the long lead time in development of new technology, such a mission probably wouldn’t fly for at least a decade.
Besides, the streaks themselves may not be the best place to look for life.
Without an ozone layer in Mars’ atmosphere the Sun bakes the planet with harsh ultraviolet light. A more cozy place for life, Grunsfeld said, would probably be a dozen feet or more below the surface, away from the UV light and where the water is less salty.
“If I were a microbe that’s where I would live,” he said.
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