SAN FRANCISCO -- A spacecraft now flying in orbit above the poles of Mars has given Earth-bound scientists fresh confidence that vast seas of ice and deep water still lie beneath the Red Planet's arid surface.
The latest news from the craft called Mars Global Surveyor is offering a wealth of surprises about the planet's ice-covered North Pole and the great bowl-shaped depression that appears to fill much of the Martian northern hemisphere.The pole itself, once believed to be huge and to contain virtually all of what might remain of any ancient Martian water, is now seen as little more than a modest ice cap holding somewhat less than half the volume of the ice now covering Greenland.
But there's plenty of water elsewhere on the planet, the scientists agree. It probably lies buried beneath surface dust in the form of several separate seas of ice perhaps a mile and a half thick, with liquid water beneath them.
"A beautiful place to look for life," said a delighted Norman H. Sleep, a Stanford University geophysicist.
New findings on the Martian surface and what may lie beneath were reported Sunday at the opening of the American Geophysical Union's annual fall meeting in San Francisco. More than 8,000 scientists who study the Earth, the oceans, the planets, the climate and the sun's influence have gathered at Moscone Center for five days of reports and debate.
The Global Surveyor spacecraft, which reached Mars 18 months ago, is now flying barely more than 75 miles above the surface -- well within the upper Martian atmosphere -- and is radioing back the first extremely high-resolution images of the north polar ice cap and the surface surrounding it for many miles.