While they are small, they are incredibly dense and hot. Here's why:
* Small: White dwarfs are the collapsed cores of stars that were once much larger (like our sun). They are about the size of Earth, but contain the mass of a star.
* Hot: White dwarfs are extremely hot because they were once the core of a star. They slowly cool down over billions of years, eventually becoming black dwarfs (which haven't been observed yet).
* Blue or white: The color of a star is determined by its temperature. White dwarfs are extremely hot and therefore appear white or bluish-white.
It's important to note that white dwarfs are not the smallest stars in the universe. There are even smaller and cooler objects like brown dwarfs, neutron stars, and black holes.
