Water, Chemistry, and Early Earth

(Caution: geeky content)

"How Water Made Earth Livable for Us - The Peroxy Way"
Space.com (November 6, 2008)

Looks like non-biological process may have provided the first bits of oxygen for Earth's atmosphere. The article is a bit technical, but worth reading for people interested in current best-guesses of what happened in the first few billion years.

I ran into a new term: ROS, or Reactive Oxygen Species. That's a sort of chemical, not something that's alive. Actually, ROS are rather bad news for living things. More, at "Reactive Oxygen Species" (MIT OpenCourseWare | Biology | The Radical Consequences of Respiration: Reactive Oxygen Species in Aging and Disease - Syllabus / Overview