All Questions
Tagged with spacetime event-horizon
108
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How exactly does Hawking radiation occur? [duplicate]
I understand some parts of the theory, I've read from here https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Supplemental_Modules_(Astronomy_and_Cosmology)/Cosmology/Carlip/...
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Why are there multiple universes in the Reissner-Nordström solution?
I am trying to make sense of the Penrose diagram of a non extremal Reissner-Nordström spacetime, that is, the solution with two horizons. The coordinates are
$$ v'=\text{exp}\left(\frac{r_+-r_-}{2r_+^...
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Conformal Diagram for Astrophysical Black Hole
I have a question about the conformal diagram of an ‘astrophysical’ black hole which forms in finite time (but with no evaporation).
Usually I see the conformal diagram presented as something similar ...
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Curvature of space in a black hole
This is a very simplistic view from an interested structural design engineer (retired).
Mass curves space. Taking the case of a sphere of uniform density the point at which you have as much mass ...
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(1+1)d collapsing null-shell?
I am trying to understand the following Penrose diagram (from https://arxiv.org/abs/1507.03489)
According to the authors, it is depicting the formation of a (1+1)d black hole from a collapsing null ...
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Space falling faster than light after it falls inside the event horizon of a black hole?
Typing my question directly so people know what I am asking, afterwards providing background and context.
Q: What does it mean when space is falling, faster than light?
(I am specifically wondering ...
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Why are inner horizons Cauchy horizons?
I know that RN black hole has two horizons, one outer one and one inner one. The outer one is the event horizon.
As far as I know, a Cauchy horizon is the boundary of the domain of dependence of a ...
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Is it possible to extract energy from black hole and decrease event horizon size faster?
So imagine a black hole that is like 3 times the mass of the sun so that there can be a bigger gravitational gradient. Assume the black hole has no accretion disk, charge, or rotation for simplicity's ...
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Why do black holes remain? [closed]
When we think about black holes as not containing matter but being regions of warped spacetime, I can't think why they don't revert to being Euclidian space more quickly. This is because I can see how ...
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Why are distances to event horizons linear with mass when gravitational effects fall off as $1/r^2$?
Black holes' gravitational effects fall off as $1/r^2$, but their event horizon grows linearly with increasing mass. $R$ (event horizon) grows the same rate as $M$ (mass of black hole). Okay lets ...
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Is it possible the Black Holes to be pure deformations in the fabric of spacetime and not an effect of super-dense matter?
Is there any theory in the literature that supports this hypothesis that BHs in their center do not have a super-dense matter singularity but are pure deformations in the fabric of spacetime itself or ...
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Using gravity to beat event horizon of black hole [duplicate]
So I know it's impossible for an object A to escape a black hole once it has crossed the event horizon, but what if it had help from the outside? Is it theoretically possible for a massive enough ...
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What distant observer would see if spaceship remains insitu just outside event horizon?
Imagine 2 spaceships found themselves just outside the event horizon of a blackhole, spaceship A tries to remain in place relative to the black hole while B accelerates around the blackhole. To a ...
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How can I make sense of black hole complementarity if the universe consist of one manifold and observers are not married to coordinates?
I'm reaching way over my head here, so bare in mind my knowledge base is at best upper undergraduate. This is, unfortunately, yet another byproduct of discussions in this page that is itself a ...
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Why does Leonard Susskind draw constant time slices around a black hole as lines passing through the origin at zero?
In this video Inside Black Holes by Leonard Susskind,
why does he draw the constant time slice as lines passing through the origin at zero?
Something seems to be contradicting to have constant time ...
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