San Antonio College Library

Sixteen million years ago, an asteroid crashing into Mars sent fragments flying into space and, eons later, one was pulled by the Earth's gravity onto the icy wilderness of Antarctica, where a geologist spotted it. In its new home at NASA's Johnson Space Center in Houston, the rock languished on a shelf for nine years. Then, in 1993, a geochemist unmasked the rock as a Martian meteorite. Before long, possible signs of once-living organisms were detected,...