Free Astronomy Magazine January-February 2015

SPACE CHRONICLES T his image from Curiosity's Mastcam shows inclined beds of sandstone interpreted as the deposits of small deltas fed by riv- ers flowing down from the Gale Crater rim and building out into a lake where Mount Sharp is now. It was taken March 13, 2014, just north of the "Kimberley" waypoint. [NASA/JPL-Caltech/MSSS] T his image shows an example of a thin-laminated, evenly stratified rock type that occurs in the "Pahrump Hills" outcrop at the base of Mount Sharp on Mars. The Mastcam on NASA's Curiosity Mars rover acquired this view on Oct. 28, 2014. This type of rock can form under a lake. [NASA/JPL-Caltech/MSSS] inated by rivers to an environment dominated by lakes." Despite earlier evidence from seve- ral Mars missions that pointed to wet environments on ancient Mars, modeling of the ancient climate has yet to identify the conditions that could have produced long pe- riods warm enough for stable wa- ter on the surface. NASA's Mars Science Laboratory Project uses Curiosity to assess an- cient, potentially habitable en- vironments and the significant changes the Martian environment has experienced over millions of years. This project is one element of NASA's ongoing Mars research and preparation for a human mission to the planet in the 2030s. "Knowledge we're gaining about Mars' environmental evolution by deciphering how Mount Sharp formed will also help guide plans for future missions to seek signs of Martian life," said Michael Meyer, lead scientist for NASA's Mars Ex- ploration Program at the agency's headquarters in Washington. sion that carved away the material between the crater perimeter and what is now the edge of the moun- tain. On the 5-mile (8-kilometer) journey from Curiosity’s 2012 landing site to its current work site at the base of Mount Sharp, the rover uncover- ed clues about the changing shape of the crater floor during the era of lakes. "We found sedimentary rocks sug- gestive of small, ancient deltas stacked on top of one another," said Curiosity science team mem- ber Sanjeev Gupta of Imperial Col- lege in London. "Curiosity crossed a boundary from an environment dom- over, is that each time it comes back it is another experiment to tell you how the environment works," Grotzinger said. "As Curiosity climbs higher on Mount Sharp, we will have a series of experiments to show patterns in how the atmo- sphere and the water and the sedi- ments interact. We may see how the chemistry changed in the lakes over time. This is a hypothesis sup- ported by what we have observed so far, providing a framework for testing in the coming year." After the crater filled to a height of at least a few hundred yards and the sediments hardened into rock, the accumulated layers of sedi- ment were sculpted over time into a mountainous shape by wind ero- n