Taken together, these missions not only will give scientists new insights into the geology, natural resources, and climate of the solar system's most Earth-like planet. If the effort uncovers definitive evidence of past or present life on Mars, it could provoke a shift in human thought as profound as the revolution sparked when Galileo discovered moons orbiting Jupiter - the first direct evidence that Earth was not the center of the universe. The notion that organic life, at least in its most elementary forms, once existed on Mars received a boost late last week when three British scientists said that they had found evidence of primitive life in a second Martian meteorite. In addition, they said, their meteorite contained organic molecules thought to have originated on Mars, as well as deposits of minerals typically formed through biological processes. On Thursday, a British team from The Open University and London's Natural History Museum announced that they had examined NASA's meteorite and agreed with the US team's findings.
Meteorite evidence remains controversial.
Yet even he and his colleague's higher estimates included temperatures that are cozy to some Earth-bound bacteria. These periods may have released large volumes of water, locked in polar caps or permafrost, that etched he Martian surface. Finding water, key for the development of life and an engine for climate, represents the overall goal of the Mars exploration program. The attempt to probe Mars for signs of life, or at least for conditions that could have fostered it, underscores how NASA is changing the way it operates. Calif. Researchers benefit from the approach, she says, because they can adapt future orbiters to follow up on discoveries from earlier Surveyor craft.