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Is Our Universe Inside Another Larger Universe?

Wormhole. Credit: Internet Encyclopedia of Science

A wormhole is a hypothetical “tunnel” connecting two different points in spacetime, and in theory, at each end of the wormhole there could be two universes. Theoretical physicist Nikodem Poplawski from Indiana University has taken things a step further by proposing that perhaps our universe could be located within the interior of a wormhole which itself is part of a black hole that lies within a much larger universe.

Whoa. I may have just lost my bearings.

As crazy as the concept of wormholes sounds, it does offer solutions to the equations of Einstein’s general theory of relativity. In fact, wormholes – also called an Einstein-Rosen Bridge — offer such a great solution that some theorists think that real wormholes may eventually be found or even created, and perhaps they could even be used for high-speed travel between two areas in space, or maybe even time travel.

However, a known property of wormholes is that they are highly unstable and would probably collapse instantly if even the tiniest amount of matter, such as a single photon, tried to travel though them.

But would it work – and could matter exist — if we were inside a wormhole inside a black hole inside another universe? Poplawski thinks so. He takes advantage of the Euclidean-based coordinate system called isotropic coordinates to describe the gravitational field of a black hole and to model the radial geodesic motion of a massive particle into a black hole.

“This condition would be satisfied if our universe were the interior of a black hole existing in a bigger universe,” Poplawski said. “Because Einstein’s general theory of relativity does not choose a time orientation, if a black hole can form from the gravitational collapse of matter through an event horizon in the future then the reverse process is also possible. Such a process would describe an exploding white hole: matter emerging from an event horizon in the past, like the expanding universe.”

So, a white hole would be connected to a black hole a wormhole, and is hypothetically the time reversal of a black hole. (Oh my, I’m now dizzy…)

Poplawski’s paper suggests that all astrophysical black holes, not just Schwarzschild and Einstein-Rosen black holes, may have Einstein-Rosen bridges, each with a new universe inside that formed simultaneously with the black hole.

“From that it follows that our universe could have itself formed from inside a black hole existing inside another universe,” he said.

IU theoretical physicist Nikodem Poplawski. Credit: Indiana University

By continuing to study the gravitational collapse of a sphere of dust in isotropic coordinates, and by applying the current research to other types of black holes, views where the universe is born from the interior of an Einstein-Rosen black hole could avoid problems seen by scientists with the Big Bang theory and the black hole information loss problem which claims all information about matter is lost as it goes over the event horizon (in turn defying the laws of quantum physics).

Poplawski theorizes that this model in isotropic coordinates of the universe as a black hole could explain the origin of cosmic inflation.

Could this be tested? Well, there is the issue that to see if an object could travel through a wormhole, the observer would have to be inside the wormhole as well, since the interior cannot be observed unless an observer enters or resides within.

A possible solution is that exotic matter wouldn’t collapse the wormhole, so we’d have to create – and be made of – exotic matter to keep the it open. But perhaps, as Poplawski proposes, if the wormhole is inside a black hole inside another universe it would work.

Anyone ready to give it a try?

Radial motion into an Einstein-Rosen bridge,” Physics Letters B, by Nikodem J. Poplawski. (Volume 687, Issues 2-3, 12 April 2010, Pages 110-113.

Sources: Indiana University
, Internet Encyclopedia of Science


Nancy Atkinson is currently Universe Today's Contributing Editor. Previously she served as UT's Senior Editor and lead writer, and has worked with Astronomy Cast and 365 Days of Astronomy. Nancy is also a NASA/JPL Solar System Ambassador.

Comments on this entry are closed.

  • DrFlimmer April 9, 2010, 6:12 AM

    You don’t know the power of the theoretical side! I must obey the mathematics.


    – Your thoughts betray you, I feel the crisis!
    – There is no crisis!

    Everyone is gathered again to destroy this thread with nonsense. Thanks, folks!

    @ LBC

    I’m quite amazed that I can follow your explanations almost until the end 😉 . This means, I’ve actually learned something in the math-courses at university.

    Btw: Your description of “strings” getting destroyed either by Hawking radiation or tidal forces (depending on the observer’s point of view) — is this also the explanation how an external observer can “see” a black hole growing?
    I mean, from the external point of view no matter actually crosses the horizon and thus the BH should not become more massive — although we know that matter falling into the BH does not feel the horizon and just enters, which means the BH grows. Is your description also a solution to this problem?

  • solrey April 9, 2010, 6:22 AM


    The irony is just too rich in digging up that one paragraph, which is mere supposition in the style of the notorious scienceapologist, in light of the subject of this article. Talk about cherry picking from a long, detailed and well cited biography on Tesla. So what if he was eccentric, most geniuses are. Einstein was a bit eccentric himself, big deal.

    The list of Tesla’s accomplishments is way too long to post here so interested parties can visit the hyperlink to Wiki above.
    The lesson is that as an empirical scientist (as opposed to theoretical mathematician) Tesla’s theories and inventions laid the foundation for all of the modern technology we enjoy today, regardless of anyones opinions about his personality or how a few questionable rogue’s might go too far with his work in their ideas.

    It’s just constant slander from some of you people.

  • Jean Tate April 9, 2010, 6:43 AM

    solrey, IVAN3MAN_AT_LARGE, Anaconda,

    The science stands on its own two feet.

    Whether you like, or dislike, a particular approach in one branch of science or other is irrelevant to the science itself.

  • IVAN3MAN_AT_LARGE April 9, 2010, 7:50 AM


    Pure fantasy dressed up as “science”.

    Oh, so what do you call “Symbols of an Alien Sky” on that Thunder[bollocks].info website that you and solrey like to frequent, then?!

    Hey, Jean Tate, why did you group me in with those two individuals, “solrey” and “Anaconda”, above?

    By referring to Nikola Tesla, I was merely pointing out the fact that pseudoscience proponents often like to associate themselves with a real genius and to quote the man out-of-context in order to give credence in support of their crazy and unsubstantiated claims, just like bloody creationists who often quote Albert Einstein out-of-context alleging his ‘belief’ in a god.

  • Olaf April 9, 2010, 8:18 AM

    @Jean Tate,

    Big respect from me to keep this forum clean. It is not an easy job.

  • Anaconda April 9, 2010, 8:33 AM

    Jean Tate wrote: “The science stands on its own two feet.”

    Please, this is only slightly better than those scientists that claimed higgs-boson particles from the future had come back to wreck the Hadron collider so Man could not discover them…ha ha ha LOL.

    Science is about empirical observation & measurement. This is mathematical jibberish posing as science.

    Jean, that you would stand up for this nonsense tells me you don’t understand or respect science.

  • DrFlimmer April 9, 2010, 8:43 AM

    The ability to destroy a thread is insignificant next to the power of science!

  • Jean Tate April 9, 2010, 9:11 AM


    I will say this to you just one more time: you do not get to dictate to anyone what the nature of science is; no one has that power.

    If you do not like how science is done, in a particular field, you are welcome to your opinions of course.

    However, using the comments on Universe Today articles to promote your personal views on the nature of science is just as unacceptable as promotion of perpetual motion machines or overunity devices is.

    If you are interested, I can suggest some internet forums which welcome discussions of the nature of science, in general.

  • bugz April 9, 2010, 10:24 AM

    believe it or not, i enjoy the endless mysteries of the universe. b/c as soon as one mystery is solved, new ones replace it. if we ever solved every mystery of the universe we’d be so bored. i think the universe is in on this awesome game of hide & seek. and if we ever do figure it out the universe will change all the rules again for kicks.

    seriously – enjoy the MYSTERY, people.

  • bugz April 9, 2010, 10:26 AM

    btw, the MYSTERY does not invalidate the search for and discovery of new knowledge.

  • Torbjorn Larsson OM April 9, 2010, 3:31 PM

    I’m not sure why this article is posted on an eminent forum such as Universe Today.

    The author to this paper, who somehow got his picture connected to it, is taking speculative and mainly rejected ideas (wormholes, white holes) and mix them to an opaque mix. Of course you can combine faulty and conflicting ideas and prove just about anything. So what?

    First, wormholes. The idea that you can use such for time travel is rejected already by a simple semiclassical study in the arxiv. It runs up against a classical mechanics paradox.

    Presumably then, as they don’t work for all spacetime connections, they don’t work for any of them. (What would pick a preferential direction?)

    Remains that they can putatively exist by quantum fluctuations. But as any proposal that geometry can fluctuate they run up against recent observations that spacetime is observationally smooth well into the Planck regime. (That gamma ray observation last year, IIRC UT had it too.)

    There is no such thing as “quantum gravity” observed. One can quantize gravity just fine (specifically, its Lagrangian) and get the required graviton out of it at low energies. That is all one can request of an effective theory like GR.

    Geometric fluctuation is, apparently, daft. Theoretically it breaks down due to divergences at the high energies requested. Observationally it breaks down because it is rejected as per above. So presumably no wormholes either.

    [And especially, on the old and quaint topic of exotic matter for macroscopic wormholes: where is the evidence?]

    Second, white holes. The interest died down as they were found to have problems. Which I don’t know, but supposedly serious enough that they aren’t discussed much anymore.

    In conclusion, a speculative work at best, of which many pollutes the arxiv.

  • Lawrence B. Crowell April 9, 2010, 3:46 PM

    DrFlimmer: The entropy of a black hole is determined by S = kA/4L_p, where L_p is the Planck unit of length, k the Boltzmann constant and A = 2pi r^2 is the area of the event horizon. The radius r = 2GM/c^2. The entropy is then a measure of the units of Planck area on the horizon. The area does change as matter is absorbed by the BH. The area is may be written as A = NL_p^2. The string length is related to the Planck length by L_p = gL_s, g = couling parameter, so the area is given by A = N(gL_s)^2. So the area does increase with each string attached to the stretched horizon.

    @Torbjorn Larsson: I agree there are no classical or macroscopic black holes. The metric fluctuations don’t exist in the way that loop variable people think. The fluctuation is concealed from the universe by the string.

    Well it looks as if it is time for my boot heels to be wandering from here. The blog page is now on page 2 of UT and the EU barbarians have scaled the walls and entered in force.


  • DrFlimmer April 10, 2010, 2:27 AM

    @ LBC

    First of all, thanks!

    Do I get this right? The outside observer (far away) does not see the particle enter the BH, but he notices the change in the entropy of the BH and/or the change in the geometry around the BH?
    A change in the geometry should be observable, because somehow the increase of mass must be communicated to the universe. Otherwise a BH could grow and grow and nothing would happen.

    However, we still shouldn’t see the particle disappear. It becomes redder and redder but does not cross the horizon, from the observers point of view far away.

    Damn, I get a knot in my head again…..

  • Lawrence B. Crowell April 10, 2010, 3:54 AM

    Good thing I checked this. I wrote “I agree there are no classical or macroscopic black holes.” I meant no classical wormholes. Classical black holes are fairly common.

    To the exterior observer at some constant proper distance from a black hole any string, which is a small but extended field configuration that appears as a particle on larger scales, slows down and is Lorentz boosted as it approaches the BH. This means that longitudinal modes (radially directed) get shortened and transverse modes appear to become elongated or distributed around the horizon. The high frequency modes of the string then appear to be of lower frequency, just as a longer string has longer standing waves than a short one. This is commensurate with the time dilation effect this exterior observes. This occurs until the string reaches a distance of d = L_p = sqrt{G-hbar/c^3) of the horizon. This is the so called stretched horizon of the BH, one Planck unit of distance from the mathematical horizon of general relativity. Now if the string has energy E < A + delta E^2, or the radius of the black hole increases by about a string length. The same occurs with the stretched horizon as well. So all the strings splayed out on the horizon now appear on a somewhat larger horizon. The event is a quantum transition, and the “old” description of the strings on the stretched horizon is in some quantum superposition with the new description at the transition. So the strings on the stretched horizon are in both positions at equivalently. This is a signature of the loss of locality in the description of fields in standard quantum field theory.

    What this means is that fields in the universe are holographically determined. The fields exterior to a black hole, or any even horizon such as the cosmological horizon, are holograms of fields on stretched horizons of one dimension lower. So the standard quantum field theoretic description of fields according to amplitudes of harmonic oscillators at every point is only a flat spacetime approximation. So the locality which underpins quantum field theory according to fields at every point on a spatial 3-dimensional surface is replaced fundamentally by a holographic description of fields on stretched horizons of one dimension lower, and these fields do not have a unique local description at every point in space. This is why one can have a string stretched out on the horizon of a BH while it has as well an equivalent description in the interior, or why the Hawking evaporation of the string is on the horizon is equivalent to its transformation as it approaches the BH singularity. The stretched horizon (ultimately a form of Dp-brane) is then dual to the interior singularity which is another Dp-brane. This is generalized into something called the AdS/CFT correspondence, where there is a duality between fields in an anti-de Sitter spacetime and conformal fields on a 5-dimensional sphere.


  • Lawrence B. Crowell April 10, 2010, 3:58 AM

    err: I wrote energy E < A + delta E^2, which is supposed read that the area of the black hole horizon increases by A' = A + delta E^2. Need more coffee :-)


  • Anaconda April 10, 2010, 5:57 AM

    What this post does demonstrate is that there is such a low level of physical constraints on the concept of so-called “black holes” (Am I allowed to question the existence of “black holes” under this regime?) that basically anything goes…

    As long as you honor the concept by calling it a “black hole” even if by conjuring up of a set of ideas it makes a mockery of the existence of “black holes” to begin with.

    In that sense, this is a very good post because it illustrates the absurdity of “black holes”.

    Because you can imagine “black holes” to be anything…as long as you call it a “black hole”.

  • Jean Tate April 10, 2010, 6:16 AM

    On the nature of science, some internet discussion forums: here, here, here, and here. They differ considerably in popularity, intellectual heft, and range.

  • Jean Tate April 10, 2010, 12:31 PM


    Which part of ‘just one more time’ did you not understand?

    Black holes have been part of physics, astrophysics, astronomy, and cosmology for several decades now, and others here have provided you with a very great deal of helpful and informative material on this topic. They have been doing so for over a year now (google “Anaconda black holes” within this domain).

    Using the comments on Universe Today articles to promote your personal views on the nature of black holes is just as unacceptable as promotion of your personal views on the nature of science is.

  • Lawrence B. Crowell April 10, 2010, 6:05 PM

    I think that in part what is happening here is what I call the certitude of minimal knowledge (CKM). This happens on a range of educational experience. A person can learn some physics up to some level, whether that be high school physics, undergraduate physics, and this is quite often seen with BS level engineers. A person learns some canonical elements of physics, where they then think the foundations of physics should conform to what they think. Such people read some layman’s literature on strange things about black holes, Hawking radiation, strings and so forth and find there is a void between what they know and the strangeness of these things. They then figure there must be a “simpler way,” and they set out on their intellectual steed Rocinante to conquer these evil windmills trampling down what should be rational physics. There are literally 10s of thousands of people like this, and the web is fertile ground for them. There are various alt-science camps, from EU stuff, or alternatives to Einsteinian relativity, to anti-quantum groups and so forth. The web is loaded with this stuff.

    Black holes exist. Without any reference to quantum gravity, strings, holography and so forth, basic astrophysical black holes clearly exist. They are virtually beyond question. Of course to understand them requires some idea of relativity theory. Einstein removed a certain obstruction from classical physics to establish this, which was to remove the notion of universal absolute time and generalize the idea of the invariant interval and local constancy of light speed. Quantum theory removed an obstruction on the distribution of energy and the notion of what was meant by a particle. Similarly with quantum gravity and cosmology further obstructions must be removed. This obstruction involves the notion of there being a locality to an event. Leonard Susskind, Juan Maldacena, and others have removed this in some partial sense. There is a question about the black hole complementarity and the nature of branes and string in the BH interior, and matters related to how our universe could be equivalent to the interior of a wormhole. These things require one to really wrap one’s brain around strange ideas and to be willing to abandon certain axioms or rules one has learned, even those in graduate school, and to replace them with more general statements. This is not easy to do, and one must first wrap one’s mind around quantum theory and relativity first, which depart from ordinary experience considerably as is, before pressing on to these foundational questions.

    This is entirely different from the CMK strategy, which is to reduce everything down to rules learned in (fill in the blank). I am aware to two people trying to reduce physics to Aristotle’s ideas of things. Einstein made a comment that it is easy to try to reduce physics to many complicated formulas based on known rules, but much harder to abstract new rules which permit a much simpler formalism. In the case of EU I find that people seem to have only a basis physics “101” idea of electromagnetism as it is, Anaconda could not answer a question about the impedance of free space (junior level problem), and yet seem to insist they have access to some crucial understanding of everything. The EU folks are in a curious way more into an ideology of physics, than an understanding of it.


  • HolyAvengerOne April 20, 2010, 7:56 PM

    Oh god. Lol.

    Lawrence B., Torbjorn L., I usually really enjoy reading your discussions and points on various subjects posted on UT. But this.

    What the fuck. Lol !!

    Thanks for the interesting topic though =)