Wikipedia has it has a pretty great article on sunspots. https://en.m.wikipedia.org/wiki/Sunspot https://en.m.wikipedia.org/wiki/Sunspot Your question got me

Wikipedia has it has a pretty great article on sunspots. https://en.m.wikipedia.org/wiki/Sunspot https://en.m.wikipedia.org/wiki/Sunspot Your question got me curious, those are called penumbral filaments. Their form has to do with the orientation of the magnetic field relative to the surface of the sun.