September 12, 2010
Galaxies were colliding long before you were born, and they will keep colliding long after us all.
Oklo: Ancient African Nuclear Reactors
Birthday · September 12, 2010
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APOD published September 12, 2010. Credit: Robert D. Loss (Curtin U.). A publication-date match, not a photo taken on your date. Independent of NASA.
The remnants of nuclear reactors nearly two billion years old were found in the 1970s in Africa. These reactors are thought to have occurred naturally. No natural reactors exist today, as the relative density of fissile uranium has now decayed below that needed for a sustainable reaction. Pictured above is Fossil Reactor 15, located in Oklo, Gabon. Uranium oxide remains are visible as the yellowish rock. Oklo by-products are being used today to probe the stability of the fundamental constants over cosmological time and distance scales and to develop more effective means for disposing of human-manufactured nuclear waste.
Image credit: Robert D. Loss (Curtin U.)