NASA Rover Finds Surprising Evidence for Mars' Watery Past

This article, written this year, 2007, says that NASA's Spirit Rover has found even more evidence that Mars is wetter than we thought. Soil kicked up and analyzed by the rover was found to be rich in silica, which needs water to be produced. This discovery occured due to a mechanical failure, as the spirit rover is getting old and one wheel no longer turns, which dragged up the soil sample. While silica is normally found in quartz on Earth, the sample on Mars was found to be non crystaline in nature.