A black hole is a place of space where gravity is so strong that no particles, not even light, can pass through it. Gravity is extremely strong because the mass has been squeezed into an infinitely tiny space. As the light cannot even break free, hence the name is the ‘black’ hole. Black holes cannot be observed directly. Only Space telescopes with special tools can help find black holes. Using special space tools shows that the stars that are very much nearer to black holes act differently than other stars because of the enormous gravitational field.
Formation of Black Holes
A black hole can be formed by the death of a massive star that has retained at least three times the solar masses. Stars with smaller masses evolve into less compressed bodies, either white dwarf stars or neutron stars.
At the end of the life of massive stars, they exhaust all the internal thermo-nuclear fuels in their core which becomes the core unstable, which causes the stars’ inner layer gravitationally collapse upon itself and the outer layer of the star to be blown away. When this happens, it causes a supernova. A supernova is a powerful explosion of a star that blasts part into space.
The structure of black holes is calculated in detail from Albert Einstein’s general theory of relativity. The singularity initiates the center of a black hole with zero volume and infinite density that pulls in all matter and energy that comes inside the event horizon. The radius of the event horizon is defined by the Schwarzschild radius. Inside the event horizon, the escape velocity exceeds the light speed; therefore, the light rays cannot escape into space.
Types of Black Holes
Scientists assume that the size of the smallest black holes is small, like an atom, but the mass of a small black hole is the same as a large mountain.
Another kind of black hole is known as a “Stellar.” Its mass can be up to 20 times more than the solar mass. Many stellar mass black holes can be there in the Earth’s galaxy, which is called the Milky Way.
The largest black holes are known as “Supermassive.” The masses of these black holes are more than 1 million times of sun’s masses. After much research, scientists have found that the center of every large galaxy contains a Supermassive black hole. The Supermassive black hole at the Galactic Center of the Milky Way galaxy is called Sagittarius A. The mass of Sagittarius A is almost equal to 4 million suns which could hold a few million Earths.
Stephen W. Hawking theorized the creation of many tiny black holes, possibly not larger than an asteroid, during the supernova. These primordial tiny black holes lose their mass over time and disappear as a result of Hawking radiation. Although black holes are still theoretical, their existence is supported by numerous observations of the phenomena corresponding to their predicted effects.