I had heard about the natural reactor before, but this Wikipedia article was my first exposure to the hypothesis that the Moon originated from an explosion in a natural fission reactor.
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...
It would have exited the solar system and be flung out across the galaxy starring Martin Landau and Barbara Bain.
An explosion big enough to crack the planet into two chunks is one thing, the series of carefully timed explosions necessary to start those chunks spinning nicely around each other is totally different.
The resulting spin of each chunk can depend on the location of the explosion in the pre-explosion earth.