September 30, 2008

Icy Snowfall Spotted in Clouds Above Red Planet Snow Detected Falling on Mars


By Marc Kaufman

The Washington Post


Icy snow falls from high in the Martian atmosphere and may even reach the planet's surface, scientists working with NASA's Phoenix Mars lander reported Monday.

Laser instruments aboard the lander detected the snow in clouds about 2 1/2 miles above the surface and followed the precipitation as it fell more than a mile toward the ground. But because of limitations with the technology, it was unclear whether any of the snow made it all the way to the Martian surface.

"Nothing like this view has ever been seen on Mars," said Jim Whiteway of York University in Toronto, lead scientist for the Canadian-supplied Meteorological Station on Phoenix. "We'll be looking for signs that the snow may even reach the ground."

In addition to finding snow, the Phoenix team reported that they had discovered material in the Martian soil that could only have formed in the presence of liquid water. While the lander's instruments had earlier found water ice below Mars' polar surface and had photographed surface fog and clouds, it has found nothing like liquid water on the surface.

The presence of nutrients and other material that once dissolved in water, however, plus the continuing presence of water as snow, vapor and ice, is leading researchers to the conclusion that Mars' polar regions might have supported life in the past - when the region was much warmer.

"Is this a habitable zone on Mars? I think we are approaching this hypothesis," said Peter Smith of the University of Arizona, the lander's principal investigator.

another discovery

The Phoenix team also said they discovered material in the Martian soil that had once been dissolved in water.

Originally published by BY MARC KAUFMAN.

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