Totally not a physicist. But, I would guess that it has to do with wiggles in space-time, since they do say it's from the vibrating of the atoms. Energy is tra

Totally not a physicist. But, I would guess that it has to do with wiggles in space-time, since they do say it's from the vibrating of the atoms. Energy is transferred through a medium via imparting of wiggles to that medium, so I think it would be reasonable to guess that it's either the vibrations moving through space-time or maybe some other field related to mass.