The simplest way to define a black hole is to say that it is a region of space where the attraction of gravity is so intense that light cannot escape from within. The origin of this phenomenon is an enormous accumulation of matter in a small space compared to the size of stars and planets. For example, an object with the mass of the sun would become a black hole if it were compressed to a diameter of 6 kilometers, while an object with the mass of the Earth would have to be compressed to the size of a marble.
Black holes get that name because they’re invisible. The only way to detect them is to observe the behavior of the gas and the stars around it, as NASA explains. For example, by observing the motion of a star, scientists can deduce whether there is a black hole in its vicinity. When a star orbits near these stars, high-energy light (such as X-rays) occurs, which scientists can detect from Earth or space.
Sometimes black holes can be strong enough to” tear ” the stars and steal their gases. An accretion disc is then formed, a mass of gas that falls over the hole forming huge spirals and heating up more as it approaches the hole. However, it is considered that there are two properties that actually define black holes: their mass and angular momentum (related to their rotation speed).
Black holes are theoretical objects?
A lot of people thought they were just mathematical curiosities. From the 1960s onwards, they understood each other much better at the theoretical level, and physicists began to take them more seriously. At the same time, astrophysical objects were discovered that could be explained If there was supposed to be a black hole hidden inside. These are the compact X-ray sources in our galaxy, and also the quasars, which are very distant galaxies with a bestial energy emission from their core.”
“For the last 20 years, this evidence has been growing ever stronger. Now we are even sure that in the center of the Milky Way there is a giant black hole of 4 million solar masses, we should soon be able to see the “shadow” of the hole itself in radio telescopes. Of course, with the detection of gravitational waves from LIGO, it can now be said that two black holes that merged 1300 million years ago have been directly “heard.” So we can already consider them objects of the real world,” concluded the physicist.
How do they originate?
Different black holes have a different origin. It is not known how they appeared, but by definition, the primordial are considered to have formed at the beginning of the universe. On the other hand, stars appear when very massive stars reach the end of their lives and collapse upon themselves because of the gravitational pull. When this happens, a supernova explosion or a weaker burst can also occur. Finally, some scientists believe that supermassive black holes formed at the same time as the galaxy they are in. It appears that its size is associated with the size and mass of its “mother” Galaxy.
But, this is not completely clear: “this may be the result of subsequent evolution. Many people believe that black holes began with masses of 50 to 100 soles, as a result of the explosion in supernovae of the first generation of stars, which were pure hydrogen and very large. And from here they grew up and formed the galaxies around them. Others believe that they formed at the same time as the gas clouds collapsed to form the galaxies.