What is a Black Hole?



Introduction


There have been several fascinating discoveries in the field of Physics and one of them is the existence of Black Holes. A black hole is the remains of the core of a planet, who’s gravitational field strength is so enormous that even light cannot escape. That’s how it gets its name i.e., black hole, as light is not reflected from a black hole and we cannot see it.


Do you wonder how do we know that they exist when we cannot see them? Let’s find out how we are able to recognise a black hole.



Creation of a Black Hole


There are billions of stars similar to our Sun in the universe who’s life cycle will come to an end at one point of time. Don’t worry, our sun is estimated to last for another 5 billion years, so we are safe (for now). The creation of a star begins as hydrogen atoms start nuclear fusion and become helium atoms. This reaction produces a lot of energy and heat, which is why our sun is so hot.


As more particles come together, a gravitational field is created and it pulls the particles together. The nuclear fusion tries to expand the particles and gravity tries to squash them. When these two forces are in balance, the star’s radius remains constant and the star is in the main sequence. Our sun is a main sequence star at the moment as its size is not changing and it produces constant heat. As the fuel (hydrogen) is running out, gravity takes over and particles will be squashed.



If the star is less than 5 times the size of our sun, it will become a red super giant and will soon die out to become a neutron star. If the size of the star is more than 10 times the size of the sun, as the fuel runs out, it will explode to become a Supernova. What remains after a Supernova is the super dense core of the planet. This core is called a black hole as it’s very dense. If planet gets very close to it, it will be sucked to the black hole and it will be destroyed.


Existence of Black Hole


Answering our initial question, while we cannot see black holes directly as light cannot be reflected from them but we can surely observe the planets around a black hole. They travel around it and they get closer to the black hole. At some point, the planets or stars get so close to the black hole that they disappear. According to Stephen Hawking, when a planet is consumed by a black hole, radiation is released in the form of X-rays. These rays are called Hawking's Rays but they haven’t still been discovered.



Conclusion


Universe is full of mysteries, some of which are quite unimaginable. Black holes are one such mysteries that scientists are still trying to comprehend. Our collective understanding of black holes revolves around several assumptions and theories created about black holes still remain to be unravelled. We hope they are unravelled soon, making black holes a bit brighter to us.

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