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Scientists Report Evidence of Saltwater Pools on Mars
By WARREN E. LEARY
ASHINGTON, March 23 --Mars was once a much warmer, wetter place, with pools of saltwater that sometimes flowed across the surface, scientists reported Tuesday.
Analyzing findings from sedimentary rocks explored by the rover Opportunity, the scientists said the rocks now appeared to have formed under a shallow bed of softly flowing water near a shoreline --not
as formerly seemed possible, through seepage from underground.
It was the first concrete evidence that water might have flowed on the Martian surface, and it provided new hints that life may have e
xist
ed there.
n"We think Opportunity is now parked on what was once the shoreline of a salty sea on Mars," Dr. Steven W. Squyres of Cornell University, principal investigator for the science payload on the Opportunity and its twin Mars exploration rover, Spirit, said at a news conference here at NASA headquarters.
"If we are correct in our interpretation, this was a habitable environment," Dr. Squyres went on. "It's a salt flat. These are the kinds of environments that are very suitable for life."
He said there was still no evidence that life existed at the site, and the Opportunity does not have the instruments to hunt for microscopic fossils. But rock formed from sediments from evaporating standing water, like those at the site, "offers excell
ent capability for preserving evidence of any biochemical or biological material that may have been in the water," he said.
The rover Opportunity landed on a plain called Meridiani Planu
m on
Jan. 25, th
ree weeks after the Spirit touched down on the opposite s
ide of the planet at a site called Gusev Crater. NASA officials said Tuesday that the two craft were operating so well that their original 90-day missions would very likely extend into the summer.
Dr. Edward Weiler, NASA's associate administrator for space science, said that when researchers first announced on March 2 that the Opportunity had found rocks that formed in the presence of water, there was some indication that the water pooled on the surface. But to be sure that they were interpreting the data correctly, Dr. Weiler said, they sent it to several outside experts for review before Tuesday's announcement.
One of those scientists, Dr. David Rubin, a sedimentary expert with the United States Geological Survey in
Santa Cruz, Calif., said he was shocked when he received the Mars pictures from NASA. "I was astonished," Dr. Rubin said. "They looked like sedimentary deposits found at a be
ach on E
arth."
D
r. Rubin told the news conference that some of the pictures showed rocks that cou
ld have been formed by particles deposited by the wind, and others by sediments put down by water. However, he said, there are features in some of the formations that require flowing water, which supports the explanations by the rover scientists.
Dr. John Grotzinger of the Massachusetts Institute of Technology, a member of the rover science team, said the rocky outcroppings examined by the Opportunity have ripple patterns and salt concentrations that are telltale signs of rock formed in standing water that sometimes flowed. This would be like some salt flats on Earth, which are periodically submerged, Dr. Grotzinger said.
To examine the patterns in the Mars outcroppings, the Opportunity used a micr
oscopic camera on its robot arm to take multiple postage-stamp-sized pictures that were put together into mosaics to examine the layering in the rock.
The close-up pictures re
vealed that
the sediments that bonded to
form the rocks were in uneven layers distorted by the ripples of flowing water,
patterns called crossbedding and festooning, Dr. Grotzinger said.
Patterns in some of the layered rocks indicate they were shaped by ripples at least two inches deep, and possibly much deeper, flowing at a speed of 4 to 20 inches per second, he said.
The patterns include distinctive, upward-turning curves characteristic of water depositing particles in layers rather than wind, he said.
In further evidence of water formation, Dr. Grotzinger said, the rover found chlorine and bromine salts in the rocks, suggesting that salt concentrations were rising while water was evaporating.
Dr. Weiler said the findings would spur efforts to expand Mars exploration and look for evidence of past
or current life. He noted that NASA planned to send the Mars Science Laboratory, a more sophisticated rover that will do detailed life-science testing, to the planet in 2009 an
d that Meridian
i was now a prime site.
To s
earch for further evidence of Martian water, the Opportunity has climbed out of its lan
ding site and will head for a crater named Endurance, 2,300 feet away. That crater, scientists said, may have even deeper rock formations.
Scientists Report Evidence of Saltwater Pools on Mars
By WARREN E. LEARY
ASHINGTON, March 23 --Mars was once a much warmer, wetter place, with pools of saltwater that sometimes flowed across the surface, scientists reported Tuesday.
Analyzing findings from sedimentary rocks explored by the rover Opportunity, the scientists said the rocks now appeared to have formed under a shallow bed of softly flowing water near a shoreline --not
as formerly seemed possible, through seepage from underground.
It was the first concrete evidence that water might have flowed on the Martian surface, and it provided new hints that life may have e
xist
ed there.
n"We think Opportunity is now parked on what was once the shoreline of a salty sea on Mars," Dr. Steven W. Squyres of Cornell University, principal investigator for the science payload on the Opportunity and its twin Mars exploration rover, Spirit, said at a news conference here at NASA headquarters.
"If we are correct in our interpretation, this was a habitable environment," Dr. Squyres went on. "It's a salt flat. These are the kinds of environments that are very suitable for life."
He said there was still no evidence that life existed at the site, and the Opportunity does not have the instruments to hunt for microscopic fossils. But rock formed from sediments from evaporating standing water, like those at the site, "offers excell
ent capability for preserving evidence of any biochemical or biological material that may have been in the water," he said.
The rover Opportunity landed on a plain called Meridiani Planu
m on
Jan. 25, th
ree weeks after the Spirit touched down on the opposite s
ide of the planet at a site called Gusev Crater. NASA officials said Tuesday that the two craft were operating so well that their original 90-day missions would very likely extend into the summer.
Dr. Edward Weiler, NASA's associate administrator for space science, said that when researchers first announced on March 2 that the Opportunity had found rocks that formed in the presence of water, there was some indication that the water pooled on the surface. But to be sure that they were interpreting the data correctly, Dr. Weiler said, they sent it to several outside experts for review before Tuesday's announcement.
One of those scientists, Dr. David Rubin, a sedimentary expert with the United States Geological Survey in
Santa Cruz, Calif., said he was shocked when he received the Mars pictures from NASA. "I was astonished," Dr. Rubin said. "They looked like sedimentary deposits found at a be
ach on E
arth."
D
r. Rubin told the news conference that some of the pictures showed rocks that cou
ld have been formed by particles deposited by the wind, and others by sediments put down by water. However, he said, there are features in some of the formations that require flowing water, which supports the explanations by the rover scientists.
Dr. John Grotzinger of the Massachusetts Institute of Technology, a member of the rover science team, said the rocky outcroppings examined by the Opportunity have ripple patterns and salt concentrations that are telltale signs of rock formed in standing water that sometimes flowed. This would be like some salt flats on Earth, which are periodically submerged, Dr. Grotzinger said.
To examine the patterns in the Mars outcroppings, the Opportunity used a micr
oscopic camera on its robot arm to take multiple postage-stamp-sized pictures that were put together into mosaics to examine the layering in the rock.
The close-up pictures re
vealed that
the sediments that bonded to
form the rocks were in uneven layers distorted by the ripples of flowing water,
patterns called crossbedding and festooning, Dr. Grotzinger said.
Patterns in some of the layered rocks indicate they were shaped by ripples at least two inches deep, and possibly much deeper, flowing at a speed of 4 to 20 inches per second, he said.
The patterns include distinctive, upward-turning curves characteristic of water depositing particles in layers rather than wind, he said.
In further evidence of water formation, Dr. Grotzinger said, the rover found chlorine and bromine salts in the rocks, suggesting that salt concentrations were rising while water was evaporating.
Dr. Weiler said the findings would spur efforts to expand Mars exploration and look for evidence of past
or current life. He noted that NASA planned to send the Mars Science Laboratory, a more sophisticated rover that will do detailed life-science testing, to the planet in 2009 an
d that Meridian
i was now a prime site.
To s
earch for further evidence of Martian water, the Opportunity has climbed out of its lan
ding site and will head for a crater named Endurance, 2,300 feet away. That crater, scientists said, may have even deeper rock formations.