Mars rover takes a sniff of the atmosphere

NASA says it Curiosity rover on Mars has taken significant steps toward understanding how the Red Planet may have lost much of its original atmosphere. The present atmosphere of Mars is 100 times thinner than Earth's, and learning what happened to it will help scientists assess whether the planet ever was habitable, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Friday. Instruments aboard the rover have taken in and analyzed samples of the atmosphere collected near the "Rocknest" site in Gale Crater where the rover is currently doing research. Findings from the Sample Analysis at Mars instruments suggest loss of a fraction of the atmosphere has been a significant factor in the evolution of the planet and that the top layers of the atmosphere may have been lost to interplanetary space. Scientists theorize that in Mars' distant past its environment may have been quite different, with persistent water and a thicker atmosphere.