The Black Vault - Mars dark streaks from seeping water?

WASHINGTON (Reuters) -- Dark streaks running down the slopes of equatorial canyons and craters on Mars could be signs that underground water is seeping to the surface, a member of a scientific research team said this week.

This does not mean there is water close to the surface of Mars in a form that would be useful to living things or potential human visitors, scientist Justin Ferris said by telephone.

"People who have visions of going to Mars and drilling down and hitting water ... we're going to have to invent some big technologies for that," said Ferris, a researcher at the U.S. Geological Survey in Colorado.

But Ferris said the research, presented this week at a meeting of the American Geophysical Union, was exciting because it hinted at sub-surface water moving around Mars' midsection.

Astronomers have long searched for signs of water on and below the Martian surface, since water -- not ice -- is seen as a requirement to supporting life as it is known on Earth. Many scientists believe Mars was once wet and warm enough to support life, though its surface is now cold, dry and inhospitable.

The research by Ferris and scientists at the University of Arizona used high-resolution images of Mars that show dark streaks more than 500 yards (meters) long running down the walls of craters and canyons.

Ferris and his co-authors believe the streaks are signs of movement of super-salty water under the Martian surface and its interaction with molten subsurface rock called magma.

The water, contained in hypersaline underground oceans, could be so loaded with salt that it would flow like syrup, and any seepage to the surface or movement downhill would be slow, Ferris said.

Underground hot springs are common on Earth, and Ferris said the same could be true on Mars, with one important difference.

"Hydrothermal systems might be common on Mars, like hot springs on Earth, perhaps never breaking the surface because it's just so inhospitable," Ferris said.

The streaks come and go, sometimes in a matter of years or decades, which on the cosmic scale is lightning-fast.

The theory of subsurface salty water causing the streaks runs counter to some scientists' idea that the dark smudges are caused by "dry processes" such as wind erosion, Ferris said.

http://www.cnn.com/2002/TECH/space/12/12/mars.water.reut/index.html