Another popular account of the idea (via Loeb) that life (especially simple life) may have been more common earlier: http://www.slate.com/articles/health_and_s

Another popular account of the idea (via Loeb) that life (especially simple life) may have been more common earlier: http://www.slate.com/articles/health_and_science/mysteries_of_the_universe/2014/02/what_if_we_ve_misunderstood_our_place_in_the_universe_a_harvard_astronomer.html http://www.slate.com/articles/health_and_science/mysteries_o...