in the core of a burned-out, collapsing star, there are so many atoms, pressed so tightly together, their electrons start to get antsy. At those kinds of pressures, the electrons aren’t bound to specific atoms, but rather are packed in together in a big atomic mess so crowded that they have to jump to higher and higher energy states to keep from all being in the same one. This creates a kind of pressure, called electron degeneracy pressure, which is strong enough to halt the collapse of the star and create an entirely new kind of object: a white dwarf.
