In my hometown newspaper there is a fascinating article entitled "New evidence suggests new view of Earth history" which suggests that geologists may have to unlearn what they think the first 700 million years of Earth's 4.5 billion year existence were really like. Up to this point, most geologists assumed Earth was a hellishly hot place. According to more recent research, however, 4 billion years ago the sun was producing 30 percent less energy than today — which would have made the Earth a much cooler place.
Here is the quote I like the best, though: "We thought we knew something we didn't," said T. Mark Harrison, a professor of geochemistry at UCLA.
