December 9, 2006
Satellite Images Point to Possibility of Geysers, Water on the Surface of MARS
By JOHN JOHNSON JR.
NASA scientists announced Wednesday that they had found evidence that water still flows over the surface of Mars - sporadic gushers that increase the possibility that the Red Planet could harbor some form of life.
Using images obtained by the Mars Global Surveyor spacecraft, the researchers concluded that geologic changes in the shapes and sizes of gullies cut into the walls of two Martian craters were likely made by flowing water.
The team looked at two sets of images taken several years apart. In both cases, the second set of images revealed a light-colored substance several hundred yards long that had not been there before, indicating that something had erupted from the ground and apparently sloshed toward the bottom of the basin.
NASA's two rovers, Spirit and Opportunity, which are on the surface of the planet, found evidence that water covered large areas of Mars billions of years ago.
"Today, we're talking about liquid water being present on Mars right now," said Ken Edgett, a staff scientist at Malin Space Sciences in San Diego, which built the camera that took the pictures released Wednesday.
"You have all heard of a smoking gun," he said. "This a squirting gun."
The findings, to be published in the journal Science, pose more issues for scientists to with. "The big questions are: how does this happen? And does it point to a habitat for life?" said Michael Meyer, lead scientist for NASA's Mars Exploration Program.
The answers will not come soon. The two rovers, which could investigate further, are both hundreds of miles away from the gullies described Wednesday.
Still, the discovery, if confirmed, would give the search for extraterrestrial life a new focus.
"Liquid water is one of only three things required by all life on Earth," the Planetary Society, a Pasadena, Calif.-based organization of space advocates, said in a statement. "If there is liquid water on Mars, that makes it even more compelling to search for life on Mars."
In another major finding, members of the science team said they found 20 new impact craters, ranging from 7 feet to 486 feet across, in other images from Global Surveyor. The scientists said the number of new craters indicated impacts from meteors could be a hazard if astronauts tried to establish a base on the planet.
The discoveries announced Wednesday were something of a surprise, because the Mars Global Surveyor, launched in 1996, is considered old technology. NASA has been using the twin rovers to painstakingly examine the mineral content of ancient rocks to try to uncover evidence of Mars' watery past over the past two years.
NASA recently announced that it had lost contact with the Global Surveyor because of a malfunction - making Wednesday's announcement all the sweeter. The craft's original mission life was supposed to last just two years.
Over the spacecraft's extended lifetime, its camera produced some 240,000 images. Finding the evidence of water required scrutinizing pictures of tens of thousands of gullies at hundreds of sites on the Martian surface.
The findings came from images taken in 2004 and 2005. The team saw a white crust or patch on the surface in gullies in the Terra Sirenum and Centauri Montes regions of southern Mars that they hadn't noticed before. Looking back to images taken in 1999 and 2001, they confirmed the deposits were new.
"The shapes of these deposits are what you would expect to see if the material were carried by flowing water," said Michael Malin, president of Malin Space Science Systems in San Diego. "They have finger-like branches at the downhill end and are easily diverted around small obstacles."
Scientists are not sure what caused the substance to retain its whitish coloration on a planet where everything is coated with dust. "This is extremely unusual for Mars," Malin said.
Malin said he believed it was some form of frost. The surface temperature on Mars ranges from minus 257 degrees Fahrenheit to minus 62 degrees. Flowing water could not remain liquid for long.
If the water is contaminated with acid, that would allow the mixture to stay wet at the surface, Malin said.
An alternative to frost is a salty crust. Both would be evidence of water flows. If it is a salty crust, the scientists said, it most likely would have been produced by water concentrating salts in the Martian soil.
Malin said he believed the water was erupting from the deep interior. "When it reaches the surface, it creates a frozen dam," he said. "Eventually, the dam breaks and the water comes bursting out."
To continue the search for water and life on Mars, Malin said he would direct a camera on the Mars Reconnaissance Orbiter, which arrived in Mars orbit this year to take over from the Global Surveyor, to look at these sites and other gullies.
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