Many people vision black holes as gigantic cosmic recycling centers. When I was at the very beginning of learning astronomy, I always supposed black hole as being the universe’s vacuum cleaner, extracting everything within its route. As intense and as cool as it may sound, it is not quite accurate. I am afraid that this is a most common misunderstanding about black holes. When we look out into the cosmos, we find that maximum number of galaxies have a supermassive black hole at their centres. The galaxies that don’t are generally dwarf galaxies or asymmetrical galaxies. Even though there are many cases where a dwarf galaxy has a black hole at its core, a general rule is that an irregular galaxy doesn’t however there are few omissions.
So should we imagine to be finally drawn into our supermassive black hole some day? Our sun and some 200 billion other stars have been in a quite well-defined orbit around the center of the Milky Way Galaxy for billions of years and would remain for forever if it weren’t for the ultimate collision with Andromeda.
Image source: N. E. Kassim, D. S. Briggs, T. J. W. Lazio, T. N. LaRosa, J. Imamura (NRL/RSD) via NASA
The cause for this is that the same physics that regulates the orbit of planets around the sun also directs the arrangements of stars around the center of the Milky Way Galaxy. Everything in our solar system circles about the sun, and has been doing the same for billions of years. The reason is the sun is pretty much the same mass as it was some 4.7 billion years ago. If you were somehow able to substitute our sun with a black hole of the same mass, the Earth and all the other planets would stay to do what they’ve been doing, the only real change would be that life wouldn’t be capable to exist as it would be very cold without the sun’s heat. In brief, a black hole is just a mass like any other in the cosmos.
When two galaxies run into each other, though, the supermassive black holes at their centers ultimately fuse. It might take a billion or more years, but it’ll ultimately occur. Two huge masses just aren’t going to favourably orbit one another. After the ultimate unite, things might settle down again, stars continue a steady orbit around the now greater supermassive black hole and the galaxy goes on. Though stars and gas that aren’t close to the black hole are pretty safe, that is not always the situation for things that are near the black hole. Stars can and do have quite constant orbits near the center of the galaxy, but the energetic supermassive black holes do have an accretion disk that is very hot and produces a lot of energy. We can normally say that anything in the accretion disk round a black hole is finally going to fall into it. The cause for this is that it is dropping gravitational energy, where as a star circling outside the accretion disk isn’t.
In the accretion disk atoms are stirring very rapidly and are continually crashing into other atoms quite aggressively. This origins the accretion disk to convert very hot. This heat means that the atoms are releasing a lot of energy, lots in the form of X-rays and radio waves. When atoms discharge this energy they drop some gravitational energy and move in nearer to the black hole.
As you can see, black holes in overall are not huge vacuums that will ultimately suck everything trapped in their gravitational impact. Most of the galaxy is in a nice steady orbit and would continue to be if it weren’t for galactic collisions. Black holes are just a mass like any other, the change being that if you get too near to them, you may lose too much gravitational energy to endure your nice steady orbit.
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