NASA: Mars Is All Wet

摘要

Almost as soon as mars Global Surveyor slipped into orbit around the Red Planet in late 1997, its main camera began snapping pictures that made scientists do a double take. The walls of some otherwise nondescript craters in Mars's southern hemisphere looked as if they had been chiseled out recently by running water. But that was impossible. The atmosphere of Mars is so thin and so cold, say the textbooks, that surface water would immediately vaporize or freeze. Eager to spy more of the enigmatic features, Michael Malin and Kenneth Edgett of Malin Space Science Systems, which built and operates the camera, scrutinized the thousands of photos that Surveyor snapped during its 1998 orbits. Nothing. But in March 1999 the camera began shooting images 10 times sharper.