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Visual evidence suggests water springs on Mars
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The appearance of these gullies in the Gorgonum Chaos region of Mars suggest that liquid water has seeped out of the surface recently
(CNN) -- Liquid water in the recent past likely formed distinct gullies and deltas on Mars, scientists said Thursday. The discovery bolstered hopes that the red planet could harbor simple life and someday host human colonists.
"The presence of liquid water on Mars has profound implications for the question of life not only in the past, but perhaps even today," NASA Associate Administrator Ed Weiler told reporters.
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Water seepage and surface runoff could have formed more than 100 rare landforms found along steep cliffs "a million years ago, a thousand years ago, perhaps yesterday," Weiler said.
Planetary geologists made the discovery by combing through
recent photos taken by the Mars Global Surveyor spacecraft. The images show the smallest features ever observed from martian orbit,
about the size of a sport-utility vehicle.
Water mostly in the south
"These are new landforms that have never been seen before on
Mars," principal investigator Michael Malin said. "We see
features that look like gullies formed by flowing water and
the deposits of soil and rocks transported by these flows."
Mostly in high latitudes and the southern hemisphere, the
sites include gullies and alluvial fans within the walls or
rims of pits, valleys and impact craters. More than 90
percent occur south of the equator and most occur on slopes
that face away from the sun.
"We were quite surprised and confused by it. It didn't fit
our model of what Mars is like," said Malin of the Surveyor
data. Malin Space Sciences operates a camera onboard the NASA
satellite, which has orbited Mars since 1997.
Scientists have long thought Mars' surface coursed with water
billions of years ago, based on evidence of liquid erosion
and signs of ancient channels and seas. But the water all but
disappeared as the planet cooled and its atmosphere thinned.
'Dragged kicking and screaming'
Water may have once been abundant on Mars, then disappeared as the planet cooled and its atmosphere thinned
Water is known to exist today as ice in the northern polar
cap and as vapor in faint clouds. But the presence of liquid
water near the surface could strengthen the theory that life
exists or once existed on Mars.
"If life ever did develop there, and if it survives to the
present time, then these landforms would be great places to
look," Weiler said.
Liquid water on Mars would also make travel to the planet
easier. Astronauts could convert water into hydrogen and
oxygen, using both as rocket fuel and the second for
Ken Edgett, the co-author of the Science Magazine report, was at first
skeptical that water formed the unusual features.
"I was dragged kicking and screaming to this conclusion," but
the visual evidence linking groundwater discharges as the
cause was too strong, he said.
The water is thought to exist about 100 to 400 meters (300 to 1,300 feet) below the surface. Malin estimated the volume of a typical flow at about 2,500 cubic meters (90,000 cubic feet), "which would fill half a dozen or so swimming pools."
Troubling questions remain
Still some troubling questions remain. Why do the discharges
take place in the coldest areas on Mars, near the poles and
on slopes facing the poles?
Malin suggested that that the groundwater could be some
exotic salty brine with unknown physical properties.
U.S. Geological Survey scientist Kenneth Tanaka suggested in
Science that frozen carbon dioxide, flashing into a liquid
and then gas, could be the culprit.
NASA plans to launch an orbiter in 2001 that will examine the
seepage sites for evidence of water-related minerals. The
agency is considering two options for an unmanned mission
to Mars in 2003.
The Mars Polar Lander was to search for martian water in
1999. The doomed robot ship was to dig beneath the surface
and study the atmosphere, but went silent as it entered the
atmosphere of the red planet.
Correspondent Miles O'Brien contributed to this report.
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March 28, 2000
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March 9, 2000
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February 23, 2000
Mars lander eludes searchers on Earth
February 8, 2000
Mars Global Surveyor
Malin Space Science Systems
The Mars Society
Mars Explorer for the Armchair Astronaut
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