Snapshots From The Meeting

摘要

The news from Mars scientists in search of water was mostly upbeat. Radar probing from orbit shows that the Frozen Sea-supposedly dirt-covered ice-"is not ice," but lava, said planetary geophysicist Roger Phillips of Southwest Research Institute in Boulder, Colorado. That's the bad news. More encouragingly, spectro-scopist Bethany Ehlmann of Brown University reported spectroscopic signs that something had long ago altered minerals in and around impact craters. That alteration looks typical of hot groundwater. And Alfred McEwen of the University of Arizona, Tucson, showed orbital images of what may be the oldest rock now on the surface. Large impacts probably lifted the so-called megabreccia from deep in the crust. It consists of great boulders embedded in a fine matrix containing water-altered minerals. McEwen's bottom line: "These may be the best places in the solar system to study…clues to the origin(s) of life."