Stuck Mars rover makes another discovery

SPACE.com: Even though NASA's Mars rover Spirit has been trapped in the sand for months, the robot has still managed to report new facts about the red planet—all by just spinning its wheels. These findings shed light on the history... More... Archived source: https://web.archive.org/web/20100114025153/http://www.spacetimeandtheuniverse.com:80/general-physics/3228-stuck-mars-rover-makes-another-discovery.html