Astronomy
The Internal Structure of White Dwarfs and Their Cooling Paths
Quick fact
White dwarfs are so dense that a sugar-cube-sized piece of their material would weigh about 1,000 kilograms on Earth, and they are expected to cool into invisible 'black dwarfs' after trillions of years—none exist yet because the universe is too young.
Why this is interesting
Imagine a star the size of Earth with the mass of the Sun—a teaspoon of its material would weigh tons. How can such an extreme object exist, and what happens to it as it ages?