Mars Briefing

Colin Dundas, a research geologist with the U.S. Geological Survey, speaks during a briefing, Thursday, Aug. 4, 2011, at NASA Headquarters in Washington. Observations from NASA's Mars Reconnaissance Orbiter (MRO) have revealed possible flowing water during the warmest months on Mars. Dark, finger-like features appear and extend down some Martian slopes during late spring through summer, fade in winter, and return during the next spring. Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars' southern hemisphere. Photo Credit: (NASA/Paul E. Alers)