Water on Mars

NASA's two Mars Exploration Rovers have spent nearly two Earth years on Mars hoping to explore the clues for past water activity on the planet. Many news stories in the past two years have discussed these clues, suggesting that a considerable amount of water was previously present on Mars. A recent study (also here) carried out at the University of Colorado at Boulder has suggested, however, that the planet was considerably less wet than previously believed. This new study is suggesting that the chemical signatures in the bedrock that were previously interpreted as a sign of past water activity, are instead the result of a "reaction of sulfur-bearing steam vapors moving up through volcanic ash deposits." As one of the research associates on the project explained, the region being studied by Mars' Exploration Rover was thus more like areas in Yellowstone and Hawaii rather than the Great Salt Lake, and the prospects of life having existed in this region in the past are much less favorable than previously believed. The image above, from NASA, shows one of the regions explored by Opportunity.