Did you know that nuclear fission reactions are natural?  Uranium fission drives many types of nuclear power plants as well as nuclear weapons.  However, these types of reactions occurred on Earth naturally, just billions of years ago.  Today, we discuss the Oklo natural fission reactors in Gabon, Africa.  These natural reactors are not only amazingly cool, but they have a really interesting discovery story and they can teach us a lot about the overlap between nuclear physics and geoscience, how uranium deposits form, and what Earth's ancient atmosphere looked like! These are important for several reasons:Geology and nuclear physics have a very intimate relationship. Basically all radiometric dating we use on Earth was developed on the back of research on Uranium nuclear physics and research into nuclear weapons/reactors. Geoscience and national security are intimately related: Nuclear forensics, or using isotope analyses to look for people enriching uranium, use the same techniques and instruments as geochronologyMany PhD geoscientists go to work in national security labs/jobsThese natural nuclear reactors help us explain Earth’s history and where Uranium deposits occur.  Another cool feature of these ancient nuclear reactors is that they may have looked much like geysers in Yellowstone National Park!  They were moderated by natural groundwater, and they cycled on and off in ~30 minute cycles. All told, these natural nuclear reactors are one of the single coolest geoscience factoid we know of!  ——————————————————Instagram: @planetgeocastTwitter: @planetgeocastFacebook: @planetgeocast Youtube: https://www.youtube.com/channel/UCJ_A82nOMu0nIvZto6zMPqgEmail: planetgeocast@gmail.comWebsite: https://planetgeocast.buzzsprout.com/