Questions tagged [white-holes]

In general relativity, a white hole is a hypothetical region of spacetime which cannot be entered from the outside, although matter and light can escape from it.

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Can Black hole eat white hole or white hole eat black hole? [duplicate]

No light can enter black holes, but is it possible for a white hole to enter a black hole? Or vice versa? Could there be black holes inside the white holes? Or were there black holes inside them that ...
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${}$Hawking radiation and Einstein-Cartan theory

As I understand it, Einstein-Cartan theory predicts that inside every black hole, there is an einstein rosenbridge connecting to a new universe that forms due to a white hole. Where does hawking ...
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Is it experimentally verifiable if we are a inside a white hole that never fully formed?

There are a lot of questions on this site about white holes, but none of them specifically answer my question. Most of these questions talk about observing white holes from outside, but do not talk ...
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If white holes are just time-reversed black holes, then can they split just not merge?

I have read this question: Equations of fundamental physics are usually time-reversible (particle physics is time-reversible in a CP or CPT sense, though) which means you can take a certain reversal ...
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Would a black hole-white hole pair self-propagate?

Would a black hole-white hole pair of equal size self propagate in the direction of the black hole? Suppose the pair are initially stationary relative to each other, with the white hole on the x axis ...
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Do white holes bend light?

White holes share a great deal of properties with black holes such as being completely characterized by rotation, mass and charge, even they have a Hawking temperature. However, I am not able to argue ...
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How do we know that quasars are not white holes?

White holes are speculative in nature. Black holes are known to exist (supermassive black holes in galactic nuclei and stellar-mass black holes in binaries). My question: if white holes are expected ...
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Black hole and white hole symmetry

NB: This question comes from an idea I had while watching this video about the video game portal and its sequel (link: https://www.youtube.com/watch?v=aj8NDOA0Sgw at 15:30 the idea of a black hole was ...
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White hole region in Kruskal–Szekeres coordinates and geodesic

We use Kruskal–Szekeres coordinates$(T,X)$ to describe black hole and white hole. For $r>2GM:$ $$T = \left(\frac{r}{2GM}-1\right)^{1/2}e^{r/4GM}\sinh\left(\frac{t}{4GM}\right)\\$$ $$X = \left(\frac{...
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Would light emitted from a white hole be red-shifted or blue-shifted?

if it's not that straight-forward, what factors would effect the resulting appearance of light emerging from a white hole?
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Is it possible we live in a white hole?

Is it possible we live in a white hole? We live in a universe that is expanding at an accelerating rate – does this not seem similar to a white hole? Could a living organism interpret a black hole as ...
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To an observer inside a black hole, why is the rest of the universe outside the black hole not a white hole?

To an observer inside a black hole, why is the rest of the universe outside the black hole event horizon not a white hole? It is a region the observer could never enter. It is a region from which ...
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Are black holes exploding just like the singularity at the big bang did, we just can't see it because of time dilation?

There is only a few question about exploding black holes but that does not address my question. Can a black hole explode? Is there a relationship between Black Holes and the Big Bang? Did the Big Bang ...
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Wormholes on Kruskal-Szekeres coordinates

Kruskal-Szekeres coordinates in the diagram are $$v=\Big(\frac{r}{2M}-1\Big)^{1/2}e^{r/4M}\sinh\Big(\frac{t}{4M}\Big)$$ $$u=\Big(\frac{r}{2M}-1\Big)^{1/2}e^{r/4M}\cosh\Big(\frac{t}{4M}\Big)$$ Region-$\...
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Near a white hole, what do lightcones look like?

In the vicinity of a Schwarzchild black hole, spacetime looks like this (at least according to a quick google search). Here, the centre of the black hole is supposed to be at $x=0$ and the event ...
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Advanced/Retarded Eddington-Finkelstein coordinates & Black/White Holes

The Schwarzschild spacetime is described by $$ds^2=-(1-\frac{r^*}{r})c^2dt^2+(1-\frac{r^*}{r})^{-1}dr^2+r^2d\theta^2+r^2\sin^2\theta d\phi^2,$$ where $r^*$ is the Schwarzschild radius. The advanced ...
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Can white holes undergo hawking radiations like black hole?

Could white holes undergo reverse hawking radiation? This is because of quantum mechanical uncertainty. So for example a pair of particles one a positive and one a negative energy particle. The ...
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What would happen if a black hole swallowed a white hole? [duplicate]

I’m just curious on this, if you can tell me then please do. Also don’t shame me for my bad question I’m just a curious little fella!
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White holes and trans-Planckian NEC instabilities

According to some recent work by Carlo Rovelli, Planckian white holes are effectively immune to perturbations, due to the fact that any perturbations that could destabilize them would have to be ...
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Do colliding black holes violate time reversal symmetry?

Two black holes can collide and merge into one bigger black hole, but not split into two. Does this mean colliding black holes violate time reversal symmetry? Related: Do black holes violate T-...
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The physical interpretation of the trip inside Kerr (black hole) spacetime

Consider then the Kerr metric$[1]$: $$ds^{2} = -\Bigg(1-\frac{2Mr}{\rho^2}\Bigg)dt^2 - \frac{2Marsin^2(\theta)}{\rho^2}[dt d\phi+d\phi dt] +$$ $$+\frac{\rho^2}{\Delta}dr^2+\rho^2d\theta^2+ \frac{sin^...
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What is a Past Event Horizon?

I've recently been informed about a few things from a reliable source: 1) Wormholes can't form via gravitational collapse 2) The event horizons in an ER bridge can't collide I understand what a ...
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Falling to a white hole

White holes, if they exist (unlikely but still fun to think about), are regions of space that can't be entered. They are time-reversals of black holes (GR is time-symmetric). However, a time reversal ...
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If the Universe were a white hole, how would inflation fit in

So, I was thinking about white holes and one theory in particular about white holes, and that is that white holes, the theoretical opposite of black holes, are each "Big Bangs". That is to say on the ...
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Any theory/author using the white hole model to explain the birth of the universe?

The maximally extended Schwarzschild solution (Kruskal diagram) envisages a white hole, which is the time-reverse of a black hole, i.e. a part of spacetime from which things can escape to us, while we ...
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A few questions about white holes

White holes are seen in the maximally extended Schwarzschild solution, they are a region from the past that appear in the theory of eternal black holes, where the singularity exists in both infinite ...
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Could you extract energy from a rotational white hole?

I understand it is possible to do it in a black hole, and its also possible to reach the event horizon of a black hole and increase its size. But in a white hole, no wave (electromagnetic or ...
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What change of coordinates makes a black hole an De Sitter space with a white hole at the other side?

I have seen that Jean-Pierre Petit describes a change in coordinates for the exterior schwarschild solution that connects two minkowski flat spaces: https://www.jp-petit.org/papers/cosmo/2015-...
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On the death and rebirth of universe in a black hole

Suppose in the end there will remain only one very large black hole, others have died. Now this black hole had absorbed all the matter and energy of the universe due to conservation principle. ...
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Is the Universe inside the event horizon of a white hole or a black hole or none? [duplicate]

I have read this question: Is the observable universe analogous to a white hole? But it does not have a satisfying answer. And this one: Is the observable region of the universe within the event ...
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Could a black hole and a white hole cause gravitational waves, if orbiting one another?

I have been puzzled by an idea that I came across while reading about white holes. But I've only just started learning about white holes, so my knowledge is severely limited. It seems I also can't ...
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Can mass still be observed in our universe after moving from a black-hole to a white-hole?

This question is based on the recent papers on LQG black-holes by Abhay Ashtekar. Quantum extension of the Kruskal spacetime and Quantum Transfiguration by Kruskal Black Holes When mass moves from ...
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What Would a White Hole Look Like?

I know it is merely hypothetical, but I am rather curious about what would it look like if it was real. For instance: a Black hole: that would have a 100% black sphere, called the event horizon ...
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Is there some physical interpretation of the parallel exterior region?

Let the maximal extension of the Schwarzschild spacetime be given. It admits as coordinates the Kruskal-Szekeres coordinates $(T,X,\theta,\phi)$ with $$T^2-X^2<1$$ since the singularity occurs at $...
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Do white holes encode the future evaporation of the black hole?

In General Relativity, white holes arise when one formulates Maximal extensions (the process by which coordinate singularities are mapped to new non-degenerate coordinates) to a geometric solution (...
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Are white holes made of exotic matter

I have recently watched Kurzgesagt in a Nutshell's video on Wormholes https://www.youtube.com/watch?v=9P6rdqiybaw and I have been thinking about white holes, and exotic matter. As I understand, white ...
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What physical laws would need to change? [closed]

My fictional worlds reside in a multiverse. More specifically, they reside in a universe within that multiverse that is very similar to ours. But here are some big differences: White holes are in ...
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Why can't white holes exist? [closed]

Why can't white holes exist? Also considering that there are infinite universes with infinite possibilities can there be a universe where white holes can exist and black holes cant, or maybe they can ...
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Is the observable universe analogous to a white hole?

My instinct is no, but my lack of understanding with respects to white holes doesn't tell me why. My thinking is this: The universe is expanding and the further away from us the faster it is expanding....
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Would a white hole have an event horizon?

I know, thee are no white holes. My question is not about their existence. I am asking about the mathematics of the white hole solution. Does it produce an event horizon or is it a naked singularity? ...
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Basics of a white hole

I know a little bit about white holes. I know that they are formed inside eternal black holes. I just need to get my facts clear. As far as I can understand, when an object goes near the event horizon ...
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Why do white holes exist?

Black holes sort of make sense. Too much mass and too much gravity, so nothing leaves it. But how and why (and where and when) can white holes exist? How can any body not let things enter it while it ...
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Direction of time inside Schwarzchild black holes

How do we know that the direction of increasing time inside the event horizon a Schwarzchild black hole is that of decreasing $r$, instead of increasing $r$? Both directions would be timelike, but how ...
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What does a white hole look like?

If I were looking at a black hole with an accretion disk, I presume it would appear something like this: I.e., the black hole is as black as black can be, and the disk on the far side of the hole is ...
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Are black and white holes linked? [duplicate]

Theoretically, if black holes are entrances where you are sucked in and you appear somewhere else, do we come out of a white hole? I ask this because a white hole is the opposite of a black hole that ...
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Is a black hole the opposite of a cosmic gusher? [closed]

If a black hole sucks things into it and a white hole ejects things, then do objects absorbed by black holes exit from a white hole?
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Are White Holes the inside of Black Holes?

I read about a theory that says that The Big Bang could be actually considered a White Hole. Than I started thinking. White Hole: an unreachable region from which stuff can come out. Black Hole: a ...
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Black hole- white hole interaction

What if a white hole and a black hole of identical size, mass and rotation(same magnitude, opposite direction) meet each other head on? The white hole would try to push away the black hole and the ...
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Black hole and critical mass? [closed]

I keep hearing about big bang, but there are no white holes and no black hole has been observed exploding. So is there a point in which a black hole reaches critical mass?
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White holes as dark energy? [closed]

I apologise right away for the possibly incompetent question, but I am not a physicist, and this just came to my mind without really thinking much about it. On one hand we struggle to find white ...
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