What is a Black Hole | What are the known types of Black Hole | Facty Universe

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What is a Black Hole?

Black holes are among the most unique, divine and controversial objects present in outer space. A black hole is believed to be a region or place of space-time where the pull of gravity is so much that neither minute particles nor the electromagnetic radiation such as light can pass through it. People can't see black holes because no light can either go in or come out of it. So,they are invisible. Space telescopes with special tools allow us to find black holes. These special tools can identify stars that are very close to a  black hole and recognize the difference in their behavior than other stars. The gravitational pull of a black hole is so strong because matter has been squeezed into a tiny space, and it happens when a star is dying. The boundary of the black hole from which no escape is possible is known as the event horizon of black hole. As it reflects no light it is sometimes believed to be an ideal black body.    

Conventionally, a black hole is  formed by the gravitational collapse of heavy objects such as stars, but they can also in theory be formed by other processes too.   

Black holes can either be big or small. The smallest black hole could be as small as just one atom, these black holes are very tiny but can have the mass of a large mountain, as mass is the amount of matter (or stuff) present in an object. The bigger ones could possibly have mass up to 20 times more than the mass of the Earth or even more than that.

What are the known  types of  a Black Hole?   

Currently, there are three types of black holes viz., Stellar black holes, Intermediate black holes, and Supermassive black holes. Now, stellar black holes are extremely dense and smaller in size as compared to others, whereas intermediate black holes are medium-sized ones , and supermassive black holes can be billions of times more massive than the Sun and are thought to be a compilation of many smaller black holes.   

Stellar black holes

 When a star is dying or in its last stage of decaying, the object may collapse or fall into itself. For smaller stars (having mass about three times that of the sun's mass), a neutron star or a white dwarf will become the new core to it. Similarly, when  collapse of a comparatively large star takes place, it continues to compress and creates a Stellar black hole, which is incredibly dense. These objects pack more than three times the mass of the sun into the diameter of a city which directly leads to a crazy amount of gravitational force pulling on objects around the black hole. They also consume the dust and gas from their surrounding galaxies, which keeps them growing in size all the way long.  

Intermediate black holes

 In the past it was believed that black holes are present in only small and large sizes, but later on numerous researches have revealed that possibility of existence of midsize  or intermediate black holes is also there. These are formed when stars in a cluster collides in a chain reaction. Numerous of these black holes forming in a particular region together could then eventually fall together in the center of a galaxy and can give rise to a supermassive black hole.   

Supermassive black holes

 It is true that small black holes populate the universe, but their considered cousins, supermassive black holes still dominate the universe. These gigantic black holes are millions or even billions times as massive as the sun, but are believed to be about the same size in diameter.  Once these giants are formed they gather dust and gas around them, which is available in abundance in the center of galaxies, allowing them to grow to an even more massive size. Supermassive black holes may be the result of hundreds or thousands of tiny black holes that merge together, Large gas clouds could also be responsible which collapsed together.  But the  collapse of a stellar cluster, a group of stars all falling together, is considered to be more common. They could also be formed from large clusters of dark matter, we still are unable to figure out what dark matter is exactly composed of because it does not emit light and cannot be directly observed.   

Coming to the end,  there are thousands of stellar black holes present in our own galaxy (Milky Way galaxy). Milky Way also have its own supermassive black hole at its center known as Sagittarius A having mass four times more than that of our Sun. And, that about existence of intermediate black holes is confirmed, but their evidence is so far debatable.