Bok
09-25-2013, 11:01 PM
Date pushed back to 3 billion years ago
More... (http://www.sciencenews.org/view/generic/id/353516/title/Oxygen_wafted_into_Earths_atmosphere_earlier_than_thought)
More... (http://www.sciencenews.org/view/generic/id/353516/title/Oxygen_wafted_into_Earths_atmosphere_earlier_than_thought)