This is nonsense. Yep, after 2 billion years this thing is now safe to touch. But that had nothing to do with it's burial.
We at least have pretty good evidence that nuclear fission products can be exposed to groundwater/hydrothermal fluids for a pretty long time.
sliken
Not sure I'd call it safe to touch. Getting with 5cm for an hour gives you as much radiation as a 8 hour flight. I wouldn't want touch it, make jewelry from it, or any substantial near promity. Not to mention if it was "only" a billion years ago it would be MUCH MUCH worse.
We at least have pretty good evidence that nuclear fission products can be exposed to groundwater/hydrothermal fluids for a pretty long time.