The origin of the Moon is still a mystery to scientists. One possible scenario includes a natural nuclear reactor running amok on ancient Earth.

The currently favored hypothesis of the formation of the Moon says that a large body impacted with young Earth and, together with the debris, formed our satellite. However, this explanation fails to reconcile with the element composition of the Moon, which is almost identical to Earth’s.

Another less popular theory suggests that proto-Moon separated from the molten Earth when it was spinning so fast that gravity barely outweighed centrifugal forces. Even a small-scale event then would eject a blob into orbit. The biggest problem with this fission theory is that the required energy of this small event was still too large.

Rob de Meijer at the University of the Western Cape and Wim van Westrenen at VU University in Amsterdam attempt to address this in a paper published on the pre-print website arxiv.org. They believe a natural nuclear explosion would do the trick.