Regardless of its name, a black hole is a huge amount of matter and energy, packed up in a small space. They are the most fascinating and weirdest things of the outer space. The density and gravitational force is so strong that nothing, even the light, can escape its attraction.
Black holes are the cold remnants of big stars. When a star reaches the final stage, it undergoes a massive explosion. As a result of it, most of the matter of the star scatter into space, but a large and cold part is left behind where no more fusion takes place.
In a star, the process of nuclear fusion produces energy and an outward pressure that counter the inward gravitational pull of the star. As a result of the explosion, the cold remnant is left with gravitational pull only. This gravitational pull forces the star to collapse upon it, resulting in an object of large mass and infinite density with zero volume. The high gravitational pull blocks the light in its orbit thus making it a dark star, known as a black hole. The mass of a black hole is ten times the mass of the sun, packed in space equal to a big city. As the light is trapped in their orbit, hence, black holes are not visible. However, there are other methods scientists use to detect its presence. Special tools are used to find black holes with the help of space telescopes. These special tools help to study how stars around black holes act differently as compared to other stars.
Black holes have complex structure and properties that are difficult to understand. The main structure of it is described here. A black hole consists of two layers important to be mentioned:
The event horizon is the point that makes the boundary around the mouth of black holes. The event horizon is that point which a particle once cross can never go back.
It is the single point where all the mass of the black hole is concentrated, and the space-time curvature becomes infinite.
Black holes vary in sizes. According to the scientist the smallest black hole can be of the size of an atom, but with the amount of mass equal to a giant mountain. The gravitational pull makes it shrink in size despite large mass. There are three types of black holes according to their sizes:
Supermassive Black Holes
These are the largest and are usually found in the centres of galaxies. Our Milky Way also has a supermassive black hole. Scientists are still completely not sure of their formation process, but according to the theory, they were formed during the formation of galaxies. As they are placed in the centre of galaxies, between tightly
packed stars and gas clouds, they continue eating up the matter and growing up. There is another theory that they might have formed as a result of merging of thousands of tiny black holes together.
Steller Black Holes
These are the ones formed as a result of massive star collapse. They usually have a mass of three times of sun or even more than that packed in a big city-sized area. Hence the gravitational pull is very strong. They also consume dust and gases from nearby galaxies.
Miniature Black Holes
Although none of their kind has been discovered yet, scientist believed them to be formed as a result of the Big Bang. As per the theory, they have a small mass, even less than the sun.
Though the term “Black Hole” was coined by John Wheeler in 1967 and the first was discovered in 1971, the
concept is much older than that. John Michelle was the first one to propose something resembling a Black Hole in 1783-84, but the theory was proved to be wrong later on. However, the theory of General Relativity, developed by Albert Einstein in 1915, describes a lot about the Black Hole phenomenon and is widely accepted by modern
Danger to Earth
One might wonder whether Earth has some danger from these Black Holes or not? Well, the fact is that there is no black hole near earth close enough. Even if a black hole replaces the sun, still its gravitational force will be equal to what the sun has now. The earth can cancel out its gravitational force just the way it does to the sun and will keep orbiting around it. However, the sun is not a star big enough to turn into a black hole.
Where the world of fiction has helped people understanding the concept of black holes through the move, there prevail some misconceptions about it as well. The concept of tunnels and wormholes that take you rapidly through space and time do not evidently exist in reality.