Weekend Feature: NASA's Search for Extraterrestrial Genomes --Was There an Earth-to-Mars Microbe Shuttle?

Weekend Feature: NASA's Search for Extraterrestrial Genomes --Was There an Earth-to-Mars Microbe Shuttle?: Scientists confirmed this week that rocks collected recently in the Moroccan desert came from the Red Planet. A little-known fact is that each year Earth is hit by by half a dozen or so one-pound or larger rocks that were...