Happy 4th anniversary for #BlackHoleFriday, a space version of #blackfridayshopping day. How big are black holes? Black holes can be large or small…just like the lines in all of the stores today. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain! So how do black holes form? Scientists think the smallest black holes formed when the universe began. Stellar black holes are made when the center of a very big star collapses. When this happens, it causes a supernova. Supermassive black holes are an altogether different story. Scientists think they were made at the same time as the galaxy they in they reside. Supermassive black holes, with their immense gravitational pull, are notoriously good at clearing out their immediate surroundings by eating nearby objects. When a star passes within a certain distance of a black hole, the stellar material gets stretched and compressed – or “spaghettified” – as ...