Black hole

THE BLACK HOLE

The term "black hole" was invented by the American physicist John Wheeler, in 1967.

In astrophysics, a black hole is a celestial object whose gravitational field is so intense that it prevents any form of matter or radiation to escape from it.

The black holes were discovered thanks to the general theory of relativity of Albert Einstein at the beginning of 20 century. According to this theory, the black hole deforms space-time so much that even the light can not escape from it.

What is the black hole?

A black hole can be formed by gravitational collapse of a star having an important mass in a very small space. A star at the end of its life stops shining because it doesn't have enough hydrogen, and the internal pressure of star is insufficient to withstand her own gravity.

The black hole is composed of a gravitational singularity a point of space on the level of which the curve of space-time is infinite.

He also comprises a horizon of events a spherical zone which delimits the area where nothing can escape from it anymore.

However, it was noted that the black hole emitted a radiation called the radiation of HAWKING, named by a famous physicist deceased last month.

This radiation would depend on the temperature and the size of the black hole. The larger it would be and the smaller evaporation would be, and the smaller it would be, the evaporation would be more important at the point to disappear.

We can note that there exist various types of blacks holes with different sizes:

The stellar black hole which has a mass ranging between 3 and 5 solar masses minimum.

The paramount black hole which has a microscopic size, it was formed after Big Bang but disappeared immediately by evaporation.

The intermediate black hole located between the stellar black hole and the supermassive black hole with for mass a few thousands of solar masses.

The supermassive black hole which has a mass of a million solar mass and which is generally in the center of a galaxy, such as for example our: Sagittarius A.

The black hole attracts all on its passage, even the light, and other black holes to form a hole even larger.

A phenomenon of collision between black holes was noted for the first time in December 2015.The scientist's detected gravitational waves which arrived on our planet.

The black hole remains still a mysterious subject which gives rise to various theories of which that of the wormhole, which would be a corridor between the black hole and the white hole which would be the exit of the black hole.

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