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August 03, 2010
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Water may still flow on Mars, scientists say
Dec. 6, 2006
Courtesy NASA
and World Science staff
NASA photos have revealed bright new deposits in two gullies on Mars that suggest water
coursed through these ditches sometime in the past seven years, researchers say. Courtesy NASA
This is “the strongest evidence to date that water still flows occasionally on the surface of Mars,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program in Washington.
Liquid water, as opposed to the water ice and vapor known on Mars, is considered necessary for life. The new findings heighten intrigue about the potential for microbial life on
the planet. The Mars Orbiter Camera on NASA’s Mars Global Surveyor provided the
new evidence in images from 2004 and 2005.
“The shapes of these deposits are what you would expect to see if the material were carried by flowing water,” said Michael Malin of Malin Space Science Systems in San Diego, Calif.
“They have finger-like
branches at the downhill end and easily diverted around small obstacles.” Malin is principal investigator for the camera and lead author of a report
on the findings published in the research journal Science.
Mars’ atmosphere is so thin and the temperature so cold that liquid water cannot persist at the surface. It would rapidly evaporate or freeze. Researchers propose that water could remain liquid long enough, after breaking out from an underground source, to carry debris downslope before totally freezing. The two fresh deposits are each several hundred meters or yards long.
Mars Global Surveyor has discovered tens of thousands of gullies on slopes inside craters and other depressions on Mars. Most gullies are at latitudes of 30 degrees or higher. Malin and his team first reported the discovery of the gullies in 2000. To look for changes that might indicate present-day flow of water, his camera team repeatedly imaged hundreds of the sites. One pair of images showed a gully that appeared after mid-2002. That site was on a sand dune, and the gully-cutting process was interpreted as a dry flow of sand.
Today’s announcement is the first to reveal newly deposited material apparently carried by fluids after earlier imaging of the same gullies. The two sites are inside craters in the Terra Sirenum and the Centauri Montes regions of southern Mars.
“These fresh deposits suggest that at some places and times on present-day Mars, liquid water is emerging from beneath the ground and briefly flowing down the slopes. This possibility raises questions about how the water would stay melted below ground, how widespread it might be, and whether there’s a below-ground wet habitat conducive to life. Future missions may provide the answers,” said Malin.
Mars Global Surveyor began orbiting Mars in 1997. The spacecraft is responsible for many important discoveries, but was lost last month.
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NASA photographs have revealed bright new deposits seen in two gullies on Mars that suggest water moved sediment through them sometime in the past seven years, researchers say. “These observations give the strongest evidence to date that water still flows occasionally on the surface of Mars,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program in Washington. Liquid water, as opposed to the water ice and vapor known to exist at Mars, is considered necessary for life. The new findings heighten intrigue about the potential for microbial life on Mars. The Mars Orbiter Camera on NASA’s Mars Global Surveyor provided the new evidence of the deposits in images taken in 2004 and 2005. “The shapes of these deposits are what you would expect to see if the material were carried by flowing water,” said Michael Malin of Malin Space Science Systems in San Diego, Calif. “They have finger-like branches at the downhill end and easily diverted around small obstacles.” Malin is principal invest igator for the camera and lead author of a report about the findings published in the journal Science. Mars’ atmosphere is so thin and the temperature so cold that liquid water cannot persist at the surface. It would rapidly evaporate or freeze. Researchers propose that water could remain liquid long enough, after breaking out from an underground source, to carry debris downslope before totally freezing. The two fresh deposits are each several hundred meters or yards long. Mars Global Surveyor has discovered tens of thousands of gullies on slopes inside craters and other depressions on Mars. Most gullies are at latitudes of 30 degrees or higher. Malin and his team first reported the discovery of the gullies in 2000. To look for changes that might indicate present-day flow of water, his camera team repeatedly imaged hundreds of the sites. One pair of images showed a gully that appeared after mid-2002. That site was on a sand dune, and the gully-cutting process was interpreted as a dry flow of sand. Today’s announcement is the first to reveal newly deposited material apparently carried by fluids after earlier imaging of the same gullies. The two sites are inside craters in the Terra Sirenum and the Centauri Montes regions of southern Mars. “These fresh deposits suggest that at some places and times on present-day Mars, liquid water is emerging from beneath the ground and briefly flowing down the slopes. This possibility raises questions about how the water would stay melted below ground, how widespread it might be, and whether there’s a below-ground wet habitat conducive to life. Future missions may provide the answers,” said Malin. Mars Global Surveyor began orbiting Mars in 1997. The spacecraft is responsible for many important discoveries, but was lost last month.