Author Topic: NASA finds evidence of recent flowing water on Mars  (Read 2328 times)

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Offline Mister Toast

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NASA finds evidence of recent flowing water on Mars
« on: September 28, 2015, 18:01:28 PM »
A NASA spacecraft circling Mars has found evidence of flowing water on the Red Planet’s surface – and in our time, not in some dim and more verdant past.
Humans may like to think Earth has the solar system’s monopoly on water, but a new study reveals that Earth’s close neighbor boasts multiple seeps of salt-laden water that were wet, or at least damp, as recently as last year.

Until now, “we thought of the current Mars as a barren, extremely dry and cold desert,” SETI Institute planetary scientist Janice Bishop, who did not take part in the research, says via email. “What is new and exciting here is that this provides evidence for liquid water on Mars in the current environment.”

Eons ago, Mars had enough water to fill enormous lakes and rivers. Scientists prospecting for the wet stuff in recent decades, however, had to content themselves with ice at the planet’s poles, small amounts of water vapor in the atmosphere and water locked up in minerals in the Martian soil. The wet Mars of billions of years ago seemed to have become a desiccated world.

But five years ago, researchers spotted mysterious dark streaks running down the warm slopes of Martian craters and mountains. The lines disappeared in the cold season and reappeared in the warm season, like spring freshets on Earth. They looked tantalizingly like a sign of liquid water, but landslides or dust couldn’t be ruled out, says study co-author Scott Murchie of the Applied Physics Laboratory.

These dark, narrow, 100 meter-long streaks called recurring slope lineae flowing downhill on Mars are inferred to have been formed by contemporary flowing water. Recently, planetary scientists detected hydrated salts on these slopes at Horowitz crater, corroborating their original hypothesis that the streaks are indeed formed by liquid water. (Photo: NASA/JPL/University of Arizona)

So Murchie and his colleagues had NASA’s Mars Reconnaissance Orbiter take a closer look. Along the mysterious lines, the spacecraft detected the signature of waterlogged molecules of perchlorate, chemicals made up of chlorine and oxygen, the scientists report in this week’s Nature Geoscience. Something is moistening Mar’s ample deposits of perchlorate, says study leader Lujendra Ojha, a graduate student at the Georgia Institute of Technology. And that something must be liquid water.
Maybe the perchlorate itself is pulling water vapor out of the Martian atmosphere. Or maybe water from melting ice flows down hillsides and soaks the perchlorate in the soil. Or maybe water is trickling out of an aquifer.

That doesn’t mean Mars has frogs and bulrushes. It’s not clear how much water is flowing on the surface, but each wet place may be less of a stream and “more of a sludge,” says planetary scientist David Vaniman of the Planetary Science Institute, who was not a part of the study team. Anyway, perchlorates are toxic.
“Water is the elixir of life,” says Mars expert Ray Arvidson of Washington University in St. Louis, who wasn’t part of the study either. Still, “I wouldn’t particularly want to live in a perchlorate fluid.” Ojha concedes that the briny water spotted by his team would not be hospitable to living creatures.

All the same, the seeps could be “an important source of water for a future human mission to Mars,” Bishop says via email, and its presence in a wide variety of Martian terrains indicates there are water cycles on Mars that Earthlings don’t fully understand, though humans have sent a fleet of sophisticated satellites and rovers to scour the planet.

“Mars is being Mars,” Vaniman says. “It’s always throwing curves at you.”