Nuclear fusion occurs in nature all the time. It’s that big hot thing in the sky. We all know that.
But does nuclear fission every occur in nature?
The answer is: yes. Once, that we know of. 1.7 billion years ago, in what is currently, but was not then, Gabon, veins of uranium ore arranged themselves just so and were affected just right so that nuclear fission spontaneously began.
But how did this affect the life forms atop the land? Did they mutate and acquire superpowers? IS THIS HOW DINOSAURS BEGAN?
No. Because multicellular life as we know it only started about 600 million years ago.
As with so much of natural history, the only witnesses were protozoa, and they weren’t in the habit of filming newsreels.