The above link is to a short primer on nuclear energy, an article from Idaho State University. I am the first to admit that I am weak on physics, and need to do some serious brushing up to understand energy policy and the thorium cycle.
What caught my eye is the section on natural nuclear reactors, and the attendant “wild theories” probably something about aliens or highly advanced vanished civilizations.
Wiki has an easier to digest article on the phenomenon here:
One nice thing about blogging is that you can actually learn a few things.