"A sedimentary basin such as this is a chemical reactor, elements get rearranged. New minerals form and old ones dissolve. Electrons get redistributed. On Earth, these reactions support life."
Astronomers are trapped in the exquisitely painful limbo of knowing exactly where to look for Martian life, but being unable to do so for fear of sabotaging the mission.
Astrobiologists are closer than ever before to finding evidence of extraterrestrial life. But with millions of planets in the universe, they first must narrow down their search.