History UsefulNotes / BLACKholes

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely or even mainly responsible for the orbits of all the stars in the galaxy. If it were removed, the orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center, but rather orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered around the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass, called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun. And yes, this means the orbital paths of all the planets are also constantly changing. Not by much, but it's measurable. Likewise, the supermassive black hole Sagittarius A* is located ''very near'' the galactic rotational center, but is not ''exactly'' at the center.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely or even mainly responsible for the orbits of all the stars in the galaxy. If it were removed, the orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center, but rather orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered around the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun. And yes, this means the orbital paths of all the planets are also constantly changing. Not by much, but it's measurable. Likewise, the supermassive black hole Sagittarius A* is located ''very near'' the galactic rotational center, but is not ''exactly'' at the center.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely or even mainly responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun. And yes, this means the orbital paths of all the planets are also constantly changing. Not by much, but it's measurable. Likewise, the supermassive black hole Sagittarius A* is located ''very near'' the galactic rotational center, but is not ''exactly'' at the center.[[/note]]

* Whirlpools: Black holes don't gain any powers of suction when they become black holes. Their mass exerts the same gravitational force as a star, planet, or any other object of the same mass. If our Sun were suddenly turned into a black hole of the same mass, the Solar system would not get "sucked in." In fact, all the orbits would stay exactly as they are now. Nothing would happen to us aside from freezing to death. If we wanted to study a black hole, we could put a probe in orbit around it the same way we put probes around other astronomical bodies. It's not going to instantly spiral to its doom (at least not any faster than it would around anything else).

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely or even mainly responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun. And yes, this means the orbital paths of all the planets are also constantly changing. Not by much, but it's measurable. Likewise, the supermassive black hole Sagittarius A* is located ''very near'' the galactic rotational center, but is not ''exactly'' at the center.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely or even mainly responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun. And yes, this means the orbital paths of all the planets are also constantly changing. Not by much, but it's measurable. Likewise, the supermassive black hole Sagittarius A* is located ''very near'' the galactic rotational center, but is not ''exactly'' at that point.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely or even mainly responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun. And yes, this means the orbital paths of all the planets are also constantly changing. Not by much, but it's measurable.[[/note]]

In short: black holes are really, ''[[MindScrew really]]'' [[EldritchLocation weird]]. It's speculated that there are supermassive black holes at the center of every galaxy and that they were there ''before'' the galaxies formed (rather than just have formed by a variety of small black holes merging into one — yes, they can do that, and the simulations of that are pretty spectacular, but predict that the actual event is downright cataclysmic for anything too close). Think of it like this: In the same way that a solar system is a large central star with many planets and other celestial objects orbiting it, a galaxy may be a supermassive black hole with ''stars'' and their solar systems orbiting around it, albeit on an even grander scale, relatively speaking. Note also that a merger of supermassive black holes can and does happen; this is in fact the inevitable result of galaxies merging, and is likely the source of quasars. At some point roughly 4 billion years in the future, this will happen to the Milky Way and Andromeda galaxies.

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely or even mainly responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun. And yes, this means the orbital paths of all the planets are also constantly changing. Not by much, but its measurable.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely or even mainly responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.0001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.000001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at its exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.000001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects, but rather both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at the exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.000001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center. [[note]]This is actually true of ''all'' orbits. Smaller objects do not actually orbit larger objects. In fact, a smaller and larger object both orbit their combined center of mass called the barycenter. If one object is significantly larger than the other(s), that barycenter may be near or below the surface of the larger object, but it will not be located at the exact center. For example, the center of mass of the solar system is not actually the very center of the Sun, but a point which is constantly changing - sometimes even outside the surface of the Sun.[[/note]]

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.000001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center.

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.000001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (which just happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, not solely the mass of the black hole at the center.

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.000001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (which just happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, and not solely the mass of the black hole at the center.

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.000001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for those few objects that are very close to it). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the ''center of mass'' of the galaxy, which ''includes'' the supermassive black hole (and which just happens to be at the center), but also includes the tens of millions of stars also clustered in the middle. The galactic orbital paths of all objects in the galaxy are caused by the ''total'' mass of the galaxy, and not solely the mass of the black hole at the center.

Another common misconception is that all the stars in the galaxy orbit the supermassive black hole at the center, the same way all the objects in the solar system orbit the Sun. However, the Sun makes up 99.8 percent of the mass of the solar system, while the supermassive black hole at the center of our galaxy (Sagittarius A*), despite indeed being supermassive, having the equivalent of 4.5 ''million'' solar masses, is only 0.000001 percent of the total mass of the galaxy. Sagittarius A* therefore cannot be solely responsible for the orbits of all the stars in the galaxy. If it were removed, the galactic orbits of almost all objects in the galaxy would not change (except for the few objects that are very close to the black hole). Strictly speaking, everything in our galaxy does not orbit the supermassive black hole at the center. Everything in the galaxy orbits the center of mass of the galaxy, which ''includes'' the supermassive black hole (which just happens to be at the center of it), but also the tens of millions of stars also clustered at the center. The galactic orbital paths of all objects in the galaxy are caused by the total mass of the galaxy, and not the mass of the black hole at the center.

* Whirlpools: Black holes don't gain any powers of suction when they become black holes. Their mass exerts the same gravitational force as a star, planet, or any other object of the same mass. If our Sun were suddenly turned into a black hole of the same mass, the Solar system would not get "sucked in." In fact, all the orbits would stay exactly as they are now. Nothing would happen to us aside from freezing to death. If we wanted to study a black hole, we could put a probe in orbit around it the same way we put probes around other astronomical bodies. It's not going to instantly spiral to its doom (at least not any faster than it would around anything else). One rather clinching argument against the idea that you can't orbit a black hole is that, well, you're orbiting one now. Well, your Sun is, along with all the stars in the galaxy, which, so far, has shown few signs of collapsing into oblivion. If you think about it, if black holes really did have such mystic suction powers, then they would have sucked everything in the universe into them by now. In fact, one of the ways that Sagittarius A* was proven to be a supermassive black hole was tracking the stars orbiting it at ''very'' high speeds.

* Whirlpools: Black holes don't gain any powers of suction when they become black holes. Their mass exerts the same gravitational force as a star, planet, or any other object of the same mass. If our Sun were suddenly turned into a black hole of the same mass, the Solar system would not get "sucked in." In fact, all the orbits would stay exactly as they are now. Nothing would happen to us aside from dying due to cold. If we wanted to study a black hole, we could put a probe in orbit around it the same way we put probes around other astronomical bodies. It's not going to instantly spiral to its doom (at least not any faster than it would around anything else). One rather clinching argument against the idea that you can't orbit a black hole is that, well, you're orbiting one now. Well, your Sun is, along with all the stars in the galaxy, which, so far, has shown few signs of collapsing into oblivion. If you think about it, if black holes really did have such mystic suction powers, then they would have sucked everything in the universe into them by now. In fact, one of the ways that Sagittarius A* was proven to be a supermassive black hole was tracking the stars orbiting it at ''very'' high speeds.

* Holes: It doesn't ''go'' anywhere. As far as the rest of the universe is concerned, you're right there.[[note]]In fact, one of the biggest problems with the definition of a black hole, mathematically, is that it seems to completely disregard the laws of thermodynamics (mass and energy are conserved via an increase in the black hole's mass and Hawking radiation). Stephen Hawking admitted that his math had a seriously big hole in the logic as a result, even though the rest added up. Theorists have posited several possible solutions to the problem.[[/note]] They don't look like they do in ScienceFiction, you can't see them from that three-quarters angle that's popular, either. Assuming there's enough stars behind it, it'd just look like a big black spot ''maybe'' with a little light visible around the outside, depending on what's on the opposite side of you, but most of it would probably be red-shifted out of the visual spectrum. Instruments would be able to see much more exciting views in the form of various other kinds of radiation.

* A hole: It doesn't ''go'' anywhere. As far as the rest of the universe is concerned, you're right there.[[note]]In fact, one of the biggest problems with the definition of a black hole, mathematically, is that it seems to completely disregard the laws of thermodynamics (mass and energy are conserved via an increase in the black hole's mass and Hawking radiation). Stephen Hawking admitted that his math had a seriously big hole in the logic as a result, even though the rest added up. Theorists have posited several possible solutions to the problem.[[/note]] They don't look like they do in ScienceFiction, you can't see them from that three-quarters angle that's popular, either. Assuming there's enough stars behind it, it'd just look like a big black spot ''maybe'' with a little light visible around the outside, depending on what's on the opposite side of you, but most of it would probably be red-shifted out of the visual spectrum. Instruments would be able to see much more exciting views in the form of various other kinds of radiation.

A black hole is not:

* Magic: Black holes don't gain any super-magic powers of suction when they become black holes. Their mass exerts the same gravitational force as a star, planet, or any other object of the same mass. If our Sun were suddenly turned into a black hole of the same mass, the Solar system would not get "sucked in." In fact, all the orbits would stay exactly as they were. Nothing would happen to us aside from dying due to cold. If we wanted to study a black hole, we could put a probe in orbit around it the same way we put probes around other astronomical bodies. It's not going to instantly spiral to its doom (at least not any faster than it would around anything else). One rather clinching argument against the idea that you can't orbit a black hole is that, well, you're orbiting one now. Well, your Sun is, along with all the stars in the galaxy, which, so far, has shown few signs of collapsing into oblivion. If you think about it, if black holes really did have such mystic suction powers, then they would have sucked everything in the universe into them by now. In fact, one of the ways that Sagittarius A* was proven to be a supermassive black hole was tracking the stars orbiting it at ''very'' high speeds.

* Magic: Black holes don't gain any super-magic powers of suction when they become black holes. Their mass exerts the same gravitational force as a star, planet, or any other object of the same mass. If our Sun were suddenly turned into a black hole, nothing would happen to us aside from dying due to cold and starvation. If we wanted to study a black hole, we could put a probe in orbit around it the same way we put probes around other astronomical bodies. It's not going to instantly spiral to its doom (at least not any faster than it would around anything else). One rather clinching argument against the idea that you can't orbit a black hole is that, well, you're orbiting one now. Well, your Sun is, along with all the stars in the galaxy, which, so far, has shown few signs of collapsing into oblivion. If you think about it, if black holes really did have such mystic suction powers, then they would have sucked everything in the universe into them by now. In fact, one of the ways that Sagittarius A* was proven to be a supermassive black hole was tracking the stars orbiting it at ''very'' high speeds.

The odd thing about this, when compared with most "normal" spherically-shaped objects in the universe, is that a black hole's ''diameter'' is directly proportional to its mass — double the Schwarzschild radius and you've multiplied the mass by 2. For the average spherical object you and I might be familiar with, such as a ball of metal or water, the volume is proportional to its mass ''cubed'' — double the radius and you've multiplied the mass by 8. This means that the larger and more massive the black hole, the ''lower its average density''.[[note]]When discussing the density of the entire region inside the event horizon, ''not'' the density of the singularity at the center.[[/note]] A black hole with 1 solar mass would have an average density on the order of 10[-[[superscript:16]]-] grams per cubic centimeter, about 1.5 quadrillion times the density of solid lead. A black hole with 4 million solar masses, on the other hand, would only have an average density of 0.00028 grams per cubic centimeter, about a quarter the density of air at sea level on the Earth, and the supermassive black hole mentioned above would be even less dense.

Stars convert hydrogen into helium via fusion, which produces enormous amounts of energy; this balances out the inward pull of gravity and keeps the star stable. However, as the star ages, the hydrogen eventually runs out and gravity begins to collapse the star. At this point, a star of sufficient mass can begin to fuse helium, starting a cycle of fusions that produces several heavier elements and turns the star into a red giant, but even that can't go on forever. Producing elements heavier than iron uses energy instead of producing it, and once the star hits this point, fusion stops and its core completely collapses in on itself; what happens from there depends entirely on the star's mass.

Until February 2016, with the [[https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves first detection of gravitational waves]] with the LIGO instrument and other similar detections in the following years[[note]]As most of the detected signals exactly match the theoretical predictions of a black hole merger[[/note]], there was no strict proof that such things exist. Granted, there ''are'' heavy low-radiating objects ("black hole candidates"), but whether some low-emission star inside an enormous gas and dust cloud is really a black hole or not... Yet there is one [[http://arxiv.org/abs/0903.1105 article]], that states: Sagittarius A* (a source of radio waves, associated with a supermassive object in the center of the Milky Way) must have an event horizon because, given the amount of superhot infalling matter we've detected around it, its surface luminosity is too low to be explained ''without'' something that traps radiation.

Black holes are collapsed stars, but not many people know ''how'' the stars have collapsed in such a way to create black holes. We don't really understand what a singularity (the heart of a black hole) even is. When we try to do the math, key calculations utterly collapse and physics melts down as the spacetime has infinite curvature. In other words, its mass has collapsed to ''[[MindScrew paradoxically zero]]'' because it's [[RhymesOnADime infinitely small and infinitely dense--thus its gravity is infinitely intense]]. They could thus be interpreted as a Real-Life case of a GameBreakingBug.