Image description from the artist:
A stylised view of nuclear fission. Nuclear fission involves the most powerful (at this scale) force of nature: the strong interaction. The view has very little physical sense. In real life, nucleons do not look like small balls, moving neutrons do not look like fire, electrons do not look like little spining balls (even if they did, they would be much much far away from the nucleus).
A larger version of the image is available
here