The Oklo natural nuclear reactor

It's an amazing story: back in the Proterozoic, where the African nation of Gabon is today, a natural body of uranium ore reached critical mass and, for the next million years, pulsed like a geyser eight times a day producing 100 kilowatts of heat. How and why it happened sheds light on even earlier doings--like the birth of the solar system. Read more...