H Y McSween Jr H Y McSween Jr

The controversial hypothesis that the ALH84001 meteorite contains relics of ancient martian life has spurred new findings, but the question has not yet been resolved. Organic matter probably results, at least in part, from terrestrial conta...

L Margulis,O West L Margulis

The Gaia hypothesis states that the atmosphere, hydrosphere, surface sediments, and life on Earth behave dynamically as a single integrated physiological system. What has been traditionally viewed as the passive environment is a highly acti...