How big are black holes?
Black holes can come in a range of sizes, but there are three main types of black holes. The black hole’s mass and size determine what kind it is. The smallest ones are known as primordial black holes. Scientists believe this type of black hole is as small as a single atom but with the mass of a large mountain. The most common type of medium-sized black holes is called “stellar.” The mass of a stellar black hole can be up to 20 times greater than the mass of the sun and can fit inside a ball with a diameter of about 10 miles. Dozens of stellar mass black holes may exist within the Milky Way galaxy.
