Posted: Wed, Feb 16, 2005, 8:46 PM ET (0146 GMT)
The Mars Exploration Rover Spirit has discovered a new class of water-altered rock, scientists said Tuesday. The rock, dubbed "Peace", contains higher concentrations of sulfate salts than any rock analyzed by the rover in Gusev Crater. Moreover, the sulfate concentrations are deep inside the rock and not just at the surface. Scientists suggest that the rock was made of volcanic rocks ground into grains and then cemented together, possibly in the presence of water. both Spirit and its twin, Opportunity, continue to operate well on the surface of Mars, more than a year after landing.
