Recent discoveries by the astronomers illustrate that BHs are the major partner to expand the galaxies. Before finding the activities of black holes, it is necessary to mention here the size and shape of BHs. A black hole is observed by three factors:
All these three factors, mass, gravity and emission of radiations, are responsible to generate accretion. McClintock is of the opinion that this is common notion among the astronomers that accretion is one of the main originators of the universe. The accretion disks have powerful influence on galaxy. The energy, produced by the motion of accretion disc around black hole, generates stars development, builds or destroys galaxy structure, and reloads the large amount of elements which has a constructive engagement for planet construction.
There is a great question, partially answered, that “what is the actual relationship between galaxy and black hole?” “Why are the black holes necessary for galaxy?” “Why do galaxies generate the black holes in it?” The astronomers have discovered that early galaxies (about 4 galaxies) were 30 times large to black holes in them. But every galaxy has black hole in center so it has been concluded that the black hole generates stars around it and then galaxy breeds (Cattaneo and Best 518–523).
Practically, almost all the big galaxies congregate a BH in it. The black holes vary in size and mass. It can be in millions of cosmological masses. As the mass and quantity of black holes increase the galaxy gains a great change in it. The activities of accretion discs enable galactic nuclei to gain the heat and eject the heavy gases from it. Jeffrey E. McClintock, Ph.D., Senior Astrophysicist, Smithsonian Astrophysical Observatory, says:
“There is strong evidence that a supermassive black hole lies at the center of the Milky Way. Astronomers believe this black hole is a radio-wave source known as Sagittarius A* (SgrA*). The