I read something recently, about them finding a "natural" nuclear reactor that they found in Africa. It was already dormant, but the thing that I found most strange of all were reports of plutonium, a synthetic element normally found only in the laboratory. I read this, and thought back to the exchange of ideas here, and I have to wonder just how natural this reactor was. Maybe through years of neglect, they've only mistaken it for natural. Maybe the equipment got stripped out, and all that's left are the byproducts.
If the civilized world were annihilated, and the less structurally sound of our buildings went with us, the radioactive elements within power plants
would still be detectable a hundred millenia afterwards. Like at Yucca Mountain. When our civilization is wiped out, I think that if the next
civilization rises, such areas would be a curiosity to them, and perhaps a honey pot. All the scrap metal the new people could want, only it makes
their fingernails and hair fall out, and strange burns. Like that time someone looted a container of caesium from a hospital in Brazil.
Time is a wheel, if you ask me.