In Astronomy, a gravitational collapse is the contraction of a massive body under the effect of its own gravitational attraction.
Description
It occurs when all the compressive forces cannot any more compensate for this attraction and maintain a balance: the star “crumbles” on itself. Gravitational collapse is one of the stages of the evolution of stars, at the same time at the beginning and towards the end of their life. It is indeed by gravitational collapse of a gas mass that the stars are formed.At the end of its life, when all the energy sources were exhausted, the star crumbles, to become a compact Objet, i.e.:
- a white Dwarf , whose electronic pressure of degeneration compensates for gravity;
- a neutron star, whose neutron pressure of degeneration compensates for gravity;
- a Black hole, whose internal physics remains unknown.
Case of the black holes
The very massive stars, exceeding the limit of Tolman-Oppenheimer-Volkoff, cannot reach a new dynamic balance by compensating for gravity. They contract until all their matter is in the Horizon of the events of a black hole in formation. One is unaware of what occurs after this moment.
There does not exist yet of physical theory describing what occurs inside a black hole. Indeed, the equations of general relativity, by being unaware of the other physical theories, predict the formation of a singularity. Quantum mechanics, on the other hand, prohibited that the matter shape contracts in on this side its wavelength. The theory of the cords, which tries the union of the two theories, cannot be tested yet.
Supernovas
The gravitational collapse of the heart of star releases so much from energy binding that the external layers are expelled by the explosion. Most impressive of them, which lead to a neutron star or a black hole, the Supernova E form.
See too
References
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