NASA: Mars Has Evidence of Saltwater
PASADENA, Calif. – A salty pool of liquid water once sloshed on Mars, ebbing and flowing in an environment that could have supported life eons before a NASA spacecraft visited the now dry and frozen spot, the space agency said.
The Opportunity rover turned up the evidence while probing an outcrop of finely layered rock at its landing site on Mars, where the six-wheeled robot landed two months ago. Scientists said the rock likely formed in water, which evaporated to leave layer after layer of sediment behind.
“If we are correct in our interpretation this was a habitable environment,” said Cornell University astronomer Steve Squyres, the mission’s main scientist. “These are the kinds of environments that are very suitable for life.”
Opportunity previously found clues that water once soaked rocks at Meridiani Planum, a broad and flat region of the planet. Those initial results left it unclear whether it was ground or surface water.
The new findings reveal those rocks likely formed at the bottom of a gently flowing body of saltwater. The rocks contain both ripple patterns and concentrations of salt that scientists consider telltale signs that they formed in standing water.
The environmental conditions required to allow a pool of water to persist on Mars confirm the planet once was a wetter and possibly warmer place. Such conditions would be conducive to life, scientists believe.
“This is a profound discovery, it has profound implications for astrobiology,” Ed Weiler, NASA’s associate administrator for space science, told a Tuesday news conference in Washington, D.C.
The water body was shallow, forming a sea, desert basin or salt flat that periodically flooded with water to depths of at least a few inches before evaporating.
The evidence does not indicate when liquid water covered the broad and flat region where Opportunity landed, or for how long. Nor does it indicate if any organisms actually lived on Mars, Squyres cautioned.
If life did flourish at the site when it was awash in water, the type of rock now found at the site is very capable of preserving evidence of any biochemical or biological material that may have been in the water, he said.
Opportunity, however, does not carry instruments capable of revealing traces of microbial life.
NASA intends to send one or more unmanned missions to Mars every 26 months, including a lander in 2009 that would be capable of prospecting for life. A mission slated for launch in 2013 would collect samples of rock and soil and return them to Earth for even more detailed analysis.
President Bush recently proposed a crewed mission to visit the planet but did not set a timeline for such an undertaking, which likely remains decades away.
Opportunity’s microscopic images of the rock outcrop revealed that the sediments that bonded together to form the rocks were shaped into ripples by gently flowing water that stood at least 2 inches deep, said mission science team member John Grotzinger, of the Massachusetts Institute of Technology.
Today, Mars is largely dry and cold. It contains trace amounts of water vapor in its atmosphere and large caps of frozen water at its poles. Spacecraft also have detected significant amounts of ice mixed in the martian soil at high latitudes.
For decades, other spacecraft in orbit around Mars have shown evidence that large amounts of liquid water once flowed across the surface of the planet, carving vast and sinuous networks of channels. The new results provide the first definitive evidence from rocks examined on Mars that liquid water once pooled on its surface.
NASA’s Jet Propulsion Laboratory launched Opportunity and its twin, Spirit, on a $820 million mission to probe Mars for exactly that type of evidence. A group of outside scientists reviewed the rover mission scientists’ findings before they were announced.
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