NASA’s Curiosity Rover Finds Evidence That Water Flowed on Mars
NASA’s Curiosity rover, still very early in its two-year search of Gale Crater for evidence of habitable environments, offered strong visual evidence this week that water flowed across the surface of Mars during a warmer earlier period.
The findings from the robot explorer also known as the Mars Science Laboratory add to the possiblity the neighboring planet once hosted biological activity.
Curiosity, which landed Aug. 6, is rolling slowly toward the base ofMountSharp, a peak comprised of layered sediments that rises 18,000 feet. Once at Sharp’s base, Curiosity will look for evidence of carbon chemistry, or organics, in the soil and rocks that would suggest some form of life was present in the past.
New images from Curiosity’s mast camera of two outcrops, Hottah and Link reveal exposed bedrock, jagged formations and small fragments of rock cemented together into a sedimentary conglomerate. Many rocks ranging in size from grains of sand to golf balls have a distinct roundness — evidence they were rolled along by water, smoothing away the edges.
“Plenty of papers have been written about channels on Mars with many different hypotheses about the flows in them,” Curiosity scientist William Dietrich of the University of California , Berkeley, said in NASA statement. “This is the first time we’re actually seeing water-transported gravel on Mars. This is a transition from speculation about the size of streambed material to direct observation of it.”
NASA’s science team estimated the water flow rate at three feet per second at depths ranging from ankle to hip deep.
“Hottah looks like someone jack-hammered up a slab of city sidewalk, but it’s really a tilted block of an ancient streambed,” said John Grotzinger, the Mars Science Laboratory project scientist of the California Institute of Technology in the same statement.
The roundness of the Martian gravel in the imagery is especially tell-tale.
“The shapes tell you they were transported and the sizes tell you they couldn’t be transported by wind. They were transported by water flow,” said Rebecca Williams, a Curiosity science co-investigator from the Planetary Science Institute in Tucson.
Scientists may seek a deeper understanding of the elemental composition of the material holding the conglomerate together, which would offer new insights into the environment in which the deposits formed. The stones may be examined as well because their travels could reveal more about the regional geology.
However, the significant find will not re-shape Curiosity’s original mission.
“A long-flowing stream can be a habitable environment,” said Grotzinger. “It is not our top choice as an environment for preservation of organics, though. We’re still going to Mount Sharp, but this is insurance that we have already found our first potentially habitable environment.”