A black hole is a space within the universe in which its gravitational field is so strong nothing can escape from it. Though perceived to be hypothetical, it has a defining characteristic called the event horizon.

This key feature of the black hole is described as a boundary in spacetime which does not permit any outside observer to see the events that are happening within it.

Its name was allegedly derived from John Wheeler who was said to have coined the term in 1967. He described it as a collapsed star that has lost its gravitational force. Anne Ewing was also credited for having given its name in a letter she sent to the AAAS.

Several researches have been done regarding black holes, especially the event horizon. Known to be invisible in the universe, the black hole can be seen through the interaction of other celestial objects that lies around its orbit. An example is observing the group of stars that are in near it.

The other way to see a black hole from Earth is to check the gas that is being pulled into the black hole. This results to the gas spiraling inwards causing it to heat up and release radiation in huge quantities.

How the notion of the black hole was born

Amateur English astronomer John Michell proposed the idea in 1783 that there can be an object strong enough to suck anything, even light, into it. In 1795, a French physicist named Pierre-Simon Laplace also came up with the same notion.

Black holes are thus linked with the general theory of relativity. It cites that if a big amount of mass is present in a very small area of space, the paths via that space is warped within into center and prevents any matter, even radiation, from escaping.

But if quantum mechanics has to be taken into account, the whole idea of black holes as a kind of prison that does not let anything out of it changes. A term called Hawking radiation states that instead of not letting things out forever, black holes may have outlets to which thermal energy leaks out.

Theories at why escaping is impossible in a black hole

It has been stated that to escape from a black hole, need to have an equal speed, the same as that of light, because black holes follow the similar concept as that of Newton's law of gravity. But that nothing can exceed the speed of light, regardless of its mass, will be able to escape from it.

But for Albert Einstein, he produced two concepts concerning the matter. First is the idea regarding spacetime, a continuum in which space and time, though different in concept, become interrelated.

This can be assumed as any object. He mentioned that any matter within spacetime cannot move freely. Instead, it has to move forward through time and that its supposed position within space will not exceed as that of the speed of time.

For the second concept, he stated that the mass, or the black hole, will cause deformities in the structures inside spacetime and a gravitational force that pulls the object within causing it to tilt.

As the distance between the object and the mass draws closer, the titling even becomes stronger. As a result, it will be impossible for the object to escape at that point. That is called event horizon.

What happen to objects when it falls in a black hole?

There are four stages experienced when falling into a black hole.

Spaghettification happen when the object nears the black hole. Its matters stretch and splits into several lines, resulting to the object to form into a string of particles. Upon crossing the event horizon, the object experiences time to slow down.

The changes that will be present with the object will be mainly the change in color as it will turn into red. From outside, everything turns blue. Upon passing through the event horizon, nothing extraordinary will take place. As the object is within the event horizon, the object will reach the singularity at its center.

As the objects hits the singularity, the falling body will be torn apart. This is even before it reaches it strikes the singularity. It is still a mystery at what happens within the singularity. To provide a description about it, a theory of quantum gravity may be needed.

Mostly, it is Hawking's and Einstein's theory that are used in determining the evolution and the formation of black holes. Newton's theory concerning gravity falls under the same category as well.

But as long as there will remain the mystifying and horrendous but nonetheless magnificent existence of black holes and the undying

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