4 types of black holes that exist in the universe
Black holes are a popular theme in science fiction films. We were all fascinated by the Gargantuan black hole that Christopher Nolan, a British-American director, depicted in his 2014 Hollywood blockbuster Interstellar. Did you know that the Gargantuan black hole is a supermassive black hole? But first things first. How are black holes formed?
Well, 'black hole' is an area in space where gravity is so strong that even light cannot escape. A black hole will form when a massive star runs out of fuel. A star is usually a giant ball of hydrogen gas used as fuel, much like how we use diesel or petrol to fuel our cars. The star continuously transforms hydrogen into other gases, producing energy. The energy pushes outward while the star's gravity pulls inward simultaneously. The star stays the same size due to this balance of pulling and pushing. However, it cannot produce the energy that pushes outward when its hydrogen supply runs low. So, the star keeps getting pulled in on itself by gravity. Gravity finally crushes the star, reducing it to the size of a black hole! A solar mass is measured by the unit of solar mass and one solar mass equals to 2×1030 kg.
In 1916, German-born theoretical physicist, Albert Einstein's general theory of relativity made the first prediction about the existence of black holes. Several years later, in 1967, American astronomer John Wheeler first used the term 'black hole'. The nearest black hole to Earth is known as 'The Unicorn', located around 1,500 light years away. Astronomers have so far identified four different forms of black holes. Here is all you need to know about the four main types of black holes.
Stellar
5-10 solar masses
The most well-known mechanism for a black hole to develop is through star death. Most dying stars will expand, lose mass, and eventually cool to produce white dwarfs. Stars like the Sun become white dwarfs once their nuclear fuel runs out. But, if the collapsing star has a mass higher than 20 times that of the Sun, its core is insufficient to prevent the collapse into the centre. There is no way to stop such a star from becoming a black hole. According to National Aeronautics and Space Administration (NASA), the Milky Way might contain 100 million to a billion stellar black holes.
Intermediate
100- 10,000 solar masses
As the name indicates, intermediate mass black holes exist between stellar mass and supermassive black holes. This particular black hole is neither too huge nor too small.
It is believed that numerous stellar mass black holes undergo a sequence of mergers with one another to create intermediate mass black holes. They begin to circle one another more quickly until they finally merge to form a single, bigger black hole. These mergers commonly take place in densely populated galaxies. The Sloan Digital Sky Survey, a US astronomical survey, has identified 305 current samples that might be potential intermediate mass black holes in our universe.
Supermassive
Above 10,000 solar masses
By merging, black holes frequently get bigger and bigger. Supermassive black holes are also predicted to follow the same pattern. One of the most convincing theories for their formation is that an uncontrolled chain reaction of colliding stars and black holes causes them to become enormous. In this scenario, the initial supermassive black hole combines and consumes increasing amounts of matter until it becomes so huge that it 'sinks' into the galaxy's centre. The black hole might merge with other intermediate and stellar mass black holes along the route, increasing in size. This technique may allow a black hole to increase in size over billions of years to a million times the mass of the Sun. The universe has around 100 billion supermassive black holes. At its heart, the Milky Way has its supermassive black hole known as Sagittarius A, which is more than four million times the mass of our Sun.
Miniature
Less than one solar mass
Miniature black holes are tiny black holes that might have developed 13.8 billion years ago. Because of the rapid expansion of space, certain regions may have been crammed into little, dense black holes smaller than the Sun!