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 caused by the light that gets pulled and never comes back, the ergosphere pushing and spinning space-time, a distortion ring caused by the distorion of the routes of passing by photons, also an accretion disk of debris, dust and hot clouds that orbit it, which would also be possible to see the back of, since it visually distorts around the black hole and also some blue shift on one side and red shift on the other, with one side brighter than the other, due to the doppler effect. Also two relativistic jets of ionized matter perpendicular to the accretion disk. Something like this:

enter image description here Image from: https://www.newscientist.com/article/dn26966-interstellars-true-black-hole-too-confusing/

But since a White Hole is the opposite of a Black Hole, for a White hole I would also expect an ergosphere (Even though a rather different and opposite looking one); instead of a black event horizon, a Hellishly Bright Sphere of light, but since nothing, nor even light, ever entered it, we would be assuming that the White hole would be creating photons out of nothing, which is absurd, so perhaps maybe not. But this is my speculation only, does anyone know a rather more based possibility?

Would there be an event horizon at all? What would it look like? Would there be relativistic jets? Could anything orbit it? Would It be tottally different?

  • $\begingroup$ Matter cannot be created from nothing, rather it is believed that white holes only exist for the biref time after their formation. It's been suggested that a group of gamma-ray-bursts and possibly even the big bang were examples of white holes. $\endgroup$
    – JMLCarter
    Commented Nov 23, 2018 at 21:58
  • 1
    $\begingroup$ @JMLCarter: It's been suggested that a group of gamma-ray-bursts and possibly even the big bang were examples of white holes. This doesn't sound quite right to me. Gamma-ray bursts can't really be white holes, because white holes can't form in our universe through gravitational collapse. The big bang isn't a white hole, because it lacks an event horizon (although they are similar in that they have past singularities). $\endgroup$
    – user4552
    Commented Nov 23, 2018 at 22:19
  • $\begingroup$ Here is some further discussion on this matter. phys.org/news/2011-05-small-white-holes.html $\endgroup$
    – JMLCarter
    Commented Nov 24, 2018 at 13:40
  • $\begingroup$ "White hole would be creating photons out of nothing, which is absurd" - It is no more absurd than a black hole destroying photons to nothing. $\endgroup$
    – safesphere
    Commented Nov 30, 2018 at 4:02

2 Answers 2


It's pretty hard to give a coherent explanation of white holes without appealing to Penrose diagrams. If you haven't seen them before, I have a nonmathematical introduction in section 11.5 of my book Relativity for Poets, as well as further examples in some of the later sections. The basic idea is that they're spacetime diagrams with light cones that make sense, but with the scales distorted, sort of like in perspective art where you have vanishing points. Here is the spacetime diagram for a black hole that forms by astrophysical collapse:

penrose diagram of astrophysical black hole

The notation $J^+$ means an idealized vanishing point where photons end up in the indefinite future. In the pictures you've been looking at, the features like the accretion disk are because you have infalling matter, like the green in this picture.

You've already seen a lot of pictures of black holes with accretion disks. Here's one that I made (intended to be pretty realistic) of one without an accretion disk:

enter image description here

This answer has some description of what you're seeing in the image above.

The reason people created theories of white holes goes something like the following. First, they made a description of a spacetime in which there was a black hole with no infalling matter. This is an eternal black hole. It can't really exist in our universe, but it's useful because it's mathematically simple. Historically, it was the first solution found to the Einstein field equations. Its Penrose diagram looks like this:

enter image description here

But mathematically, this can be extended to a larger spacetime that looks like this:

enter image description here

This is called the maximal extension of the Schwarzschild spacetime. It has two singularities, a past one (bottom dashed line) and a future one (top dashed line). It also has two event horizons, enclosing two interior regions, II and IV. In addition to the exterior spacetime I, which is like our universe, it also has a second exterior spacetime III, which is like a parallel universe.

General relativity can't predict what comes out of a past singularity such as the Big Bang or the singularity inside the white hole. As John Earman of the University of Pittsburgh puts it, anything could pop out of such a singularity, including "green slime or your lost socks." So if you like, you can imagine stuff popping out of there if you like, or you can say that nothing does. There is no physical law that tells us what to choose.

The Penrose diagram shows us where matter can end up later if it's in a certain place now, because it has to be in the future light cone. So any socks or whatever that come out of the past singularity could exit either into region I or region III. If it came out into region I, we would see it as stuff being ejected from the event horizon.

instead of a black event horizon, a Hellishly Bright Sphere of light

If the past singularity produces photons, then those would come out, and the white hole could look bright. If the past singularity doesn't produce photons, then it would look black.

If you look at how the light cones work out, it is not possible for the white hole to have an accretion disk of matter falling into it. It does attract matter (its mass is positive), but its event horizon lies in the past light cone of all matter in region I.

Because it has positive gravity, matter can orbit it, and it can deflect light rays, as in the simulated image of the black hole above.

By the way, if you were living in the maximal extension of the Schwarzschild spacetime, you could jump into the black hole, and then during the time you spent in region II, you would be able to see both region I and region III. This type of suicide mission would be the only way to see region III.

  • 1
    $\begingroup$ So you're saying that a White Hole has two ends, one in the past and other in the future/present, and possibly different parallel universes? Also, if the mass is positive than it can suck things in? So why can't it have an accretion disk? Sorry if those questions show some misunderstanding of the diagrams, that's because I've never seen those types of diagrams before. $\endgroup$ Commented Nov 24, 2018 at 19:22
  • $\begingroup$ The green collapsing matter diagram is incorrect. A star collapses to a line, not point: inspirehep.net/record/864268/files/fig1.png $\endgroup$
    – safesphere
    Commented Nov 30, 2018 at 4:41
  • $\begingroup$ @safesphere: The green collapsing matter diagram is incorrect. A star collapses to a line, not point Your interpretation is incorrect. There is no contradiction between the two diagrams. There is no metric at the singularity, so we can't say whether or not there are distinct points on it or not. $\endgroup$
    – user4552
    Commented Sep 22, 2019 at 18:02
  • $\begingroup$ @ArthurdeSouzaJúnior: So you're saying that a White Hole has two ends, one in the past and other in the future/present There are two singularities, one in the past and one in the future. The future one is the black hole, the past one the white hole. Also, if the mass is positive than it can suck things in? So why can't it have an accretion disk? As a crude analogy, consider the big bang. All the matter has positive mass, and yet the big bang can't suck things in. That's because it's a spacelike surface in the past, not a timelike surface. $\endgroup$
    – user4552
    Commented Sep 22, 2019 at 18:04
  • $\begingroup$ @BenCrowell Sure you can in the asymptotic limit. As it is evident from the Schwarzschild metric, the geometry of the inner space is a 3-cylinder shrinking in time asymptotically to an infinitely long Euclidean line of the singularity. You do have the metric arbitrarily close to the singularity and close enough to understand that the singularity is not compact, but infinitely extended in the spatial direction of the Schwarzschild coordinate $t$. You can see the correct diagram here showing that a star does not collapse to a point: physics.stackexchange.com/questions/496050 $\endgroup$
    – safesphere
    Commented Sep 22, 2019 at 18:26

I have no scientific background like most people answering here. Only a creative one. So where they lose centuries on calculations, I use imagination.

Ant to put it bluntly if you want my best explanation of what a white hole would look like, at 12:00 o'clock during the day, just look up.

I can't put 4-5 letters with mathematical signs between them to explain it, but if a white hole truly acts opposite of a black hole, stars would be my first suspects.

They continuously eject matter and have event horizons that lock celestial objects around them, but never leaving them reach the center.

And if the next question is how this works in regard of the black hole at the other end of the duality, my belief is that a white hole represents the singularity at the center of a black hole, and they shouldn't be seen as two separate entities, more like the nucleus and the outer edge of the same 4th dimensional sphere.

If someone is kind enough to help me with the letters and mathematical symbols to test this, I would be forever grateful. It won't change anything, but we would know more.

If not, I guess I will have to waste a few centuries to learn how to explain this in science lingo...

  • $\begingroup$ And I beg of the scientific community to stop calling them holes. If we lived in a 2D universe it would be enough, but as our universe is 3D, let's call them spheres already... $\endgroup$
    – N0-B0DY
    Commented Dec 12, 2022 at 2:43
  • $\begingroup$ This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review $\endgroup$
    – Miyase
    Commented Dec 12, 2022 at 5:43
  • $\begingroup$ @N0-B0DY they are holes in the spacetime fabric (i.e. manifold), and from that perspective the universe is not actually 3D but rather 4D. $\endgroup$ Commented Dec 12, 2022 at 12:40
  • $\begingroup$ Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. $\endgroup$
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    Commented Dec 12, 2022 at 17:51

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