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Questions tagged [gravitational-collapse]

Use for questions related to the creation/possibility of black holes in a certain situation, singularities, the contraction of an astronomical object due to its own gravity, and the re-collapse of our universe. Do not use for questions relating to normal gravitational attraction.

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How does gravity acts on the electrons to collapse a neutrons star or white dwarfs against the degeneracy pressure?

if electrons is considered as quantum particle in case neutron star (alluding to quantum statistics) how does gravity makes the star collapse? considering the fact that electrons are quantum particles ...
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2answers
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Calculation of Gravitational Collapse time

The answers to Gravitational collapse and free fall time (spherical, pressure-free) describe the calculation of collapse time for a gas. For the case of neutral hydrogen gas with number density $10^4$/...
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1answer
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Gravitational collapse (conservation of energy)

During gravitational collapse, gravitational potential energy of the gas is converted to its internal kinetic energy so the internal energy of the clous of gas is said to be increased But isn't ...
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1answer
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How does a distant observer see matters that “form” an initial black hole?

I did see Can black holes form in a finite amount of time? but it does not seem to discuss how a distant observer would see evolution of collapsing matters that form a black hole. Does it view these ...
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1answer
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Photon gas into a Black hole

Can a photon gas have so much energy that it collapse into a black hole just like a regular star?
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1answer
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Do cosmic voids have to exist to prevent gravitational collapse of the Universe?

Since a black hole radius is 2 times the mass, it seems like any infinite distribution of matter has to have voids of increasing size as the scale changes in order for the whole Universe not to ...
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What does black hole formation and evaporation actually look like as viewed from far away?

Many people on Physics SE (myself included) have been confused about what black hole formation and evaporation look like when viewed from far away. For example: Does any particle ever reach any ...
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0answers
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Situation after Saini & Stojkovic's paper on unitarity in gravitational collapse and non-formation of black holes?

In their paper, Anshul Saini and Dejan Stojkovic [1] claimed that by calculations it is possible to demonstrate that in a gravitational collapse of a disk, an event horizon is never made for a far ...
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Elementary flatness - Gravitational collapse of a massless scalar field

Choptuik pioneered numerical studies of the gravitational collapse of massless scalar fields in spherically symmetric, asymptotically flat spacetime. In his papers (e.g. https://arxiv.org/pdf/gr-qc/...
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In what sense is ''Oppenheimer-Snyder collapse a time reversed closed FRW model"?

In what sense is ''Oppenheimer-Snyder collapse a time reversed closed FRW model" ? That is, "Are closed FRW metric (k=1) and the geometry inside the collapsing homogeneous matter same?" If yes, how? ...
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0answers
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Is there a de Sitter or FRW collapse solution for black holes, similar to the Oppenheimer-Snyder-collapse?

I know the Oppenheimer-Snyder-solution and the formation of the black hole event horizon during the collapse. Is there a similar solution for a dynamical collapse, embedded in asymptotic de Sitter ...
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Gravitational collapse

Suppose one has a self gravitating finite sphere of radius $r_{c}$ filled with a gas, i.e. the density satisfies $\rho(r\geq r_{c})=0,$ and a radial pressure that satisfied the equation of state $p(r)=...
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Would a grid of $10^{57}$ hydrogen atoms collapse?

Assume we have a gridded cube of $10^{57}$ hydrogen atoms, with all atoms 1mm apart from other atoms. This 'cube cloud' is in an area of space that would otherwise be at zero g, were it not for the ...
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Lorentz transformed Scharwzschild solution

A question that has always intrigued me is: "Imagine a star moving as it evolves into a black hole, Ignore the effect of debris from the supernova. Assume also that before the collapse, the star was ...