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A short history of nearly everythingThey do indeed get through a lot of rocks at the ANU. Back in BennettБЂ™s office after our tour, I noticed hanging on her wall a poster giving an artistБЂ™s colorfully imaginative interpretation of Earth as it might have looked 3.5 billion years ago, just when life was getting going, in the ancient period known to earth science as the Archaean. The poster showed an alien landscape of huge, very active volcanoes, and a steamy, copper-colored sea beneath a harsh red sky. Stromatolites, a kind of bacterial rock, filled the shallows in the foreground. It didnБЂ™t look like a very promising place to create and nurture life. I asked her if the painting was accurate. БЂњWell, one school of thought says it was actually cool then because the sun was much weaker.БЂ«(I later learned that biologists, when they are feeling jocose, refer to this as the БЂњChinese restaurant problemБЂ«-because we had a dim sun.) БЂњWithout an atmosphere ultraviolet rays from the sun, even from a weak sun, would have tended to break apart any incipient bonds made by molecules ...» |
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