Astronomers also suspect that a class of objects called intermediate-mass black holes exist in the universe, although evidence for them is so far debatable. These small vortices of darkness may have swirled to life soon after the universe formed with the big bang, some 13.7 billion years ago, and then quickly evaporated. The tiniest members of the black hole family are, so far, theoretical. The Milky Way hosts its own supermassive black hole at its center known as Sagittarius A* (pronounced “ay star”) that is more than four million times as massive as our sun. Supermassive black holes, predicted by Einstein's general theory of relativity, can have masses equal to billions of suns these cosmic monsters likely hide at the centers of most galaxies. Thousands of these stellar-mass black holes may lurk within our own Milky Way galaxy. Packing all of that bulk-many times the mass of our own sun-into such a tiny point gives black holes their powerful gravitational pull. If its mass collapses into an infinitely small point, a black hole is born. In the stellar remnants of a supernova, however, there are no longer forces to oppose that gravity, so the star core begins to collapse in on itself.

While the star was alive, nuclear fusion created a constant outward push that balanced the inward pull of gravity from the star's own mass. Such a burst flings star matter out into space but leaves behind the stellar core. In their final stages, enormous stars go out with a bang in massive explosions known as supernovae. Learn about the types of black holes, how they form, and how scientists discovered these invisible, yet extraordinary objects in our universe. At the center of our galaxy, a supermassive black hole churns.

Super masive blackhole