NASA: Mars Curiosity rover finds rocky signs of once-gushing stream
NASA’s Curiosity rover has found evidence of strong streams that once gushed across the Martian surface, mission scientists said Thursday.
Curiosity landed in Gale Crater on Aug. 5. But now, less than a couple of months into the Mars Science Laboratory’s two-year mission, the Red Planet rover used its Mast Camera to examine rocks on its way to Glenelg Intrigue. Glenelg has caught scientists’ eyes because the odd spot serves as a junction between three different types of terrain.
The two outcrops in between, named Link and Hottah, have provided some exciting results in the meantime. The mission’s head scientist, Caltech geologist John Grotzinger, described the outcrop at Hottah as a raised cement section in a ”jackhammered urban sidewalk,” possibly caused by an impact on the surface.
The telltale rocks are made of sandy rock riddled with large pebbles. The shape of those pebbles tells the scientists that the rocks must have traveled a long way, bumping into each other and smoothing out the rough edges. The relatively large size of many of those stones – some the size of a golf ball – tells them that water, not wind, must have carried them.
Such rocks could have traveled 20 to 25 miles and started out rough and blocky, big as a football, before being ground down to their current size, the scientists said.
“This is a rock that was formed in the presence of water, and we can characterize that water as being a vigorous flow,” Grotzinger said.
Currently, Curiosity is located about two to four miles from an alluvial fan – a triangle-shaped network of channels on a slope that indicates water may have pushed material downward, spreading as it flowed.
-- Amina Khan, Los Angeles Times