No matter their starting size, black holes can grow throughout their lives, slurping gas and dust from any objects that creep too close. 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. An astronaut who ventured too close and was sucked into a black hole would be pulled apart by the overpowering gravity.At the center of our galaxy, a supermassive black hole churns. Objects that fall into black holes are literally stretched to breaking point. Quasars may be hundreds of times brighter than even the largest ordinary galaxies. Supermassive black holes also power active galaxies and ancient galaxies known as quasars. These may be millions or billions of times heavier than our Sun. Most galaxies, including the Milky Way, have supermassive black holes at their centres. What is left of the star – still several solar masses - collapses into an area only a few kilometres across. These 'stellar-mass' black holes form when a heavyweight star, about 10 times heavier than the Sun, ends its life in a supernova explosion. Many of them are only a few times more massive than the Sun. As the discs swirl around them like a whirlpool, they become extremely hot and give off X-rays.īlack holes come in many different sizes. Many of them are surrounded by discs of material. The gravitational pull of this region is so great that nothing can escape – not even light.Īlthough black holes cannot be seen, we know they exist from the way they affect nearby dust, stars and galaxies. This catastrophic collapse results in a huge amount of mass being concentrated in an incredibly small area. Instead, it is a region of space where matter has collapsed in on itself. A black hole does not have a surface, like a planet or star. Black holes are the strangest objects in the Universe.
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