Free Astronomy Magazine January-February 2015

JANUARY-FEBRUARY 2015 SPACE CHRONICLES O bservations by NASA’s Curiosi- ty Rover indicate Mars' Mount Sharp was built by sediments deposited in a large lake bed over tens of millions of years. This interpretation of Curiosity’s finds in Gale Crater suggests an- cient Mars maintained a climate that could have produced long-last- ing lakes at many locations on the Red Planet. "If our hypothesis for Mount Sharp holds up, it challenges tall, its lower flanks exposing hun- dreds of rock layers. The rock layers – alternating between lake, river and wind deposits – bear witness to the repeated filling and evaporation of a Martian lake much larger and longer-lasting than any previously examined close-up. "We are making headway in solving the mystery of Mount Sharp," said Curiosity Project Scientist John Grotzinger of the Cal- ifornia Institute of Technology in Pasadena, California. "Where there's now a mountain, there may have once been a series of lakes." Curiosity finds clues to how water helped shape martian landscape by NASA the notion that warm and wet con- ditions were transient, local, or on- ly underground on Mars,” said Ash- win Vasavada, Curiosity deputy proj- ect scientist at NASA's Jet Propul- sion Laboratory in Pasadena. “A more radical explanation is that Mars' ancient, thicker atmosphere raised temperatures above freezing globally, but so far we don't know how the atmosphere did that." Why this layered mountain sits in a crater has been a challenging ques- tion for researchers. Mount Sharp stands about 3 miles (5 kilometers) T his illustration depicts a lake of water partially filling Mars' Gale Crater, receiving runoff from snow melting on the crater's northern rim. [NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS]