Astronomy
Degenerate Electron Pressure in White Dwarf Interiors
Quick fact
In a white dwarf, the electrons are so tightly packed that they are forced into the highest possible energy states, creating a pressure that can support the star against gravity—but only if the star's mass is below about 1.4 times the Sun's mass, known as the Chandrasekhar limit.
Why this is interesting
You might think that a star that has exhausted its nuclear fuel would simply cool and fade forever. But some stars, like white dwarfs, hold themselves up with a strange quantum pressure that seems to defy gravity—yet only up to a point.