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Study: Our 3D Universe Could Have Originated From a 4D Black Hole

New submitter TaleSlinger sends this quote from Nature: "Afshordi's team realized that if the bulk universe contained its own four-dimensional (4D) stars, some of them could collapse, forming 4D black holes in the same way that massive stars in our Universe do: they explode as supernovae, violently ejecting their outer layers, while their inner layers collapse into a black hole. In our Universe, a black hole is bounded by a spherical surface called an event horizon. Whereas in ordinary three-dimensional space it takes a two-dimensional object (a surface) to create a boundary inside a black hole, in the bulk universe the event horizon of a 4D black hole would be a 3D object — a shape called a hypersphere. When Afshordi's team modeled the death of a 4D star, they found that the ejected material would form a 3D brane surrounding that 3D event horizon, and slowly expand. The authors postulate that the 3D universe we live in might be just such a brane — and that we detect the brane's growth as cosmic expansion. 'Astronomers measured that expansion and extrapolated back that the Universe must have begun with a Big Bang — but that is just a mirage,' says Afshordi."

32 of 337 comments (clear)

  1. Sorry by krovisser · · Score: 5, Funny

    Turtles all the way down.

    1. Re:Sorry by NoNonAlphaCharsHere · · Score: 3, Funny

      Mmmmmmm. Branes.

    2. Re:Sorry by FredGauss · · Score: 5, Insightful

      Turtles all the way down.

      Funny, but also Insightful? Turtles all the way down, or turtles all the way up? If we inhabit the 3D manifold that resides in a black hole within a 4D bulk universe, and observe 3D black holes (with a 2D event horizon), does this imply 1D black holes inside of the black holes that we observe (with 0D black holes inside...). Is the 4D bulk universe a black hole in a 5D hyper-bulk universe within a 6D ... Is there a physicist in the house that can shed more light on this than the article/paper?

  2. Re:NO! by VortexCortex · · Score: 4, Funny

    Falling into a black hole you are stretched like strands of spaghetti.
    The tendrils of a sun's magnetic fields are like great bands of spaghetti as well.

    However, this is merely confirmation bias. Clearly, with all the roundness everywhere His meaty balls have the most influence.

  3. Uhhh... what did he just say to us? by pspahn · · Score: 5, Funny

    So whatever a 4D star is, when it explodes there is a 3D layer that represents the event horizon. We live in this layer. One side of the layer is a 4D black hole, and the other side of the layer is some other kind of nothingness. Yeah?

    Is there someone here I can offer monetary compensation to for them to comprehend this summary for me?

    --
    Someone flopped a steamer in the gene pool.
    1. Re:Uhhh... what did he just say to us? by rasmusbr · · Score: 5, Interesting

      If I understood it correctly they mean that on the other side is a universe with 4 spatial dimensions.

      Think of it this way: in a universe with 3 spatial dimensions a black hole has a 2-d surface (shaped roughly like the surface of a sphere) as its event horizon. On the inside of the surface is the black hole. On the outside is the rest of the universe. Generalizing this to a hypothetical universe with 4 spatial dimension, a black hole in such a universe would have a 3-d "surface" surrounding it with the black hole inside of the surface and the rest of the universe outside of it.

      By the way, there is already an idea floating around about how the edge of the visible universe seems be a bit like the event horizon of a black hole. Once something has passed the edge of the visible universe it is effectively lost to us, a bit like when something passes the event horizon of a black hole.

    2. Re:Uhhh... what did he just say to us? by Rockoon · · Score: 5, Interesting

      What will really cook your noodle is if you calculate the mass of a black hole whos event horizon the size of the visible universe, its within an order of magnitude of the suspected mass of the visible universe (including dark matter.)

      A common misconception is that black holes require singularities. Simple thought experiments show it differently.. for example, imagine living in a universe with a mass about that of a black hole that would have an event horizon that is just a little bit smaller than the universe. Now imagine that universe contracting. You can see that as it contracts it will eventually become small enough to form an event horizon without a singularity.

      --
      "His name was James Damore."
    3. Re:Uhhh... what did he just say to us? by plover · · Score: 4, Funny

      Damn! Just when 3D printers started getting reasonably priced, now I have to go out and buy a 4D printer? And to print a 4D universe you're telling me I'll need a 5D printer?

      Theoretically, would a 4D printer use "strings" instead of "filament"?

      --
      John
    4. Re:Uhhh... what did he just say to us? by pspahn · · Score: 5, Funny

      All the way up to 20D, at which point the DM's mother informs him it's time for dinner (corndogs and mac'n'cheese yet again).

      --
      Someone flopped a steamer in the gene pool.
    5. Re:Uhhh... what did he just say to us? by mysidia · · Score: 5, Interesting

      By the way, there is already an idea floating around about how the edge of the visible universe seems be a bit like the event horizon of a black hole. Once something has passed the edge of the visible universe it is effectively lost to us

      Because we can only see things that have sent light back towards us, AND that return light has already reached us. If something is further away from earth, than the distance that light could have possibly travelled back from the object towards earth from the time that the object was at that distance, then by induction: we cannot see the object yet.

      Because near the rim of the universe.... the universe is expanding faster than the speed of light; so it's far enough, that light would take longer to travel back to where earth is, than the duration the universe has existed.

      Furthemore: since the universe can continue to expand at a rate faster than the speed of light --- the light travelling back towards earth, can never overtake the rate of the universe's expansion, and find its way back to us.

      It is kind of like an infinite treadmkill ---- very similar to the concept of a gravitational well that is so deep not even light can escape.

      We have an outer rim of our universe expanding so quickly, that not even the very timespace; the spatial dimensions or the passage of time can escape it.

    6. Re:Uhhh... what did he just say to us? by rasmusbr · · Score: 4, Interesting

      Well, I'm not a physicist either and I could be wrong but I think that there are two equivalent views of what a black hole is. The holographic view is pretty strange...

      The stuff that supposedly sits at the event horizon in the holographic view is not matter; it is information. My understanding is that the event horizon of a black hole can basically be though of as a data storage device that stores scrambled information about everything that the hole has swallowed, except for the information about the stuff that it has since spit out.

      I imagine it works something like this: when the black hole swallows some matter the information content in that matter (that is the entropy) gets stored on the horizon and the horizon expands to make room for it. When the hole spits out a particle the horizon "erases" the information/entropy of that particle and the horizon contracts to make sure there isn't any empty "disk space".

    7. Re:Uhhh... what did he just say to us? by ChromaticDragon · · Score: 5, Informative

      Umm... No.

      http://en.wikipedia.org/wiki/Observable_universe

      http://en.wikipedia.org/wiki/Future_of_an_expanding_universe

      http://en.wikipedia.org/wiki/Big_Rip

      We have no idea how large the universe is. But the current estimates of the radius of the observable universe is about 45 billion light years. That's how "far" we can see. And this is indeed due to the expansion of the universe essentially moving distances apart faster than light can travel. Furthermore, it's not just that we won't "catch up"... It seems rather likely that it's gonna get worse over time - to the point we won't be able to see much at all (relatively speaking).

    8. Re:Uhhh... what did he just say to us? by LWATCDR · · Score: 4, Insightful

      I think they are just making this crap up to mess with us at this point.

      --
      See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
    9. Re:Uhhh... what did he just say to us? by JesseMcDonald · · Score: 4, Insightful

      a black hole in such a universe would have a 3-d "surface"

      I'm trying to decide whether this makes any more sense than a square circle. 3D surface is a contradiction in terms. A surface is 2 dimensional by definition.

      The term "surface" normally refers to a two-dimensional shape in 3D space, but it can be generalized to any number of dimensions (a hypersurface). One example would be a hypersphere (x**2 + y**2 + z**2 + w**2 = 1), which has three orthogonal directions of movement along the hypersurface and encloses a four-dimensional space. Movement tangent to the hypersphere it would seem like movement in normal 3D Euclidean space, except that if you travel far enough in any direction you'll eventually end up back where you started.

      Once something has passed the edge of the visible universe it is effectively lost to us

      Only until we build a bigger telescope.

      It's not a matter of how large or sensitive the telescope is; if something is far enough away, the expansion of the space between the object and ourselves causes the distance between us to increase faster than the speed of light, meaning light from the object can never reach us. Once something reaches that distance it's cut off from us for good (or at least as long as the universe continues to expand).

      It's not really the same because anything that collides with a black hole will cease to exist. ... Even if the collapsed star's gravity did not stop the photons from exiting it would effectively vanish out of existence.

      These are one and the same thing. Black holes are not particularly special; the event horizon isn't some solid barrier things crash into. It's merely the point of no return, beyond which escape velocity exceeds the speed of light. Objects which enter a black hole "cease to exist" in exactly the same sense as objects which pass beyond the visible universe: any effect involving the object would need to propagate faster than the speed of light to reach us.

      --
      "The state is that great fiction by which everyone tries to live at the expense of everyone else." - Bastiat
    10. Re:Uhhh... what did he just say to us? by mysidia · · Score: 4, Informative

      Yes. universal expansion occurs at a speed faster than the speed of light.

      The expansion of the universe causes distant galaxies to recede from us faster than the speed of light, if comoving distance and cosmological time are used to calculate the speeds of these galaxies. However, in general relativity, velocity is a local notion, so velocity calculated using comoving coordinates does not have any simple relation to velocity calculated locally[16] (see comoving distance for a discussion of different notions of 'velocity' in cosmology). Rules that apply to relative velocities in special relativity, such as the rule that relative velocities cannot increase past the speed of light, do not apply to relative velocities in comoving coordinates, which are often described in terms of the "expansion of space" between galaxies. [....]
      There are many galaxies visible in telescopes with red shift numbers of 1.4 or higher. All of these are currently traveling away from us at speeds greater than the speed of light. Because the Hubble parameter is decreasing with time, there can actually be cases where a galaxy that is receding from us faster than light does manage to emit a signal which reaches us eventually.[18][19] However, because the expansion of the universe is accelerating, it is projected that most galaxies will eventually cross a type of cosmological event horizon where any light they emit past that point will never be able to reach us at any time in the infinite future,[20] because the light never reaches a point where its "peculiar velocity" towards us exceeds the expansion velocity away from us

    11. Re:Uhhh... what did he just say to us? by HuguesT · · Score: 4, Informative

      Replying to myself, sorry. Actually orbits are stable in dimension d=2 and 3 and no other. In both orbits are elliptical. With d=2 the center of mass is the center of the ellipse. For d=3 the center of mass is at one of the focal points.

      http://physics.stackexchange.com/questions/50142/gravity-in-other-dimensions-than-3-and-stable-orbits

    12. Re:Uhhh... what did he just say to us? by wonkey_monkey · · Score: 4, Insightful

      A surface is 2 dimensional by definition.

      No, it isn't. It's two-dimensional only by everyday common experience.

      Once something has passed the edge of the visible universe it is effectively lost to us

      Only until we build a bigger telescope.

      No, we'll never see it. The light from there will never reach us.

      It's not really the same because anything that collides with a black hole will cease to exist.

      No, it won't.

      YANAP

      --
      systemd is Roko's Basilisk.
    13. Re:Uhhh... what did he just say to us? by Rockoon · · Score: 4, Interesting

      This is not quite right: according to the Penrose singularity theorem, the existence of an event horizon implies that spacetime is singular (more precisely: geodesically incomplete).

      You have overstepped the theorem. The theorem states that a singularity must eventually form if there is an event horizon, not that a singularity must exist at all points in time that the event horizon exists.

      Remember than in a hollow sphere of any mass, gravity is neutral at all points that arent edge points. The sphere can be massive enough that the schwarzschild radius (aka the event horizon) can be outside the sphere, yet inside gravity is neutral and space-time remains flat. Entropy will eventually collapse the sphere, but thats eventually... not immediately.

      --
      "His name was James Damore."
  4. Re:Get out the bong by binarylarry · · Score: 5, Informative

    That would be Cypress Hill, not ICP.

    --
    Mod me down, my New Earth Global Warmingist friends!
  5. It's not a paper in Nature by 93+Escort+Wagon · · Score: 4, Informative

    It's a news story on their website talking about a preprint paper posted on Arxiv.

    --
    #DeleteChrome
  6. What's their point? by istartedi · · Score: 4, Funny

    What's their point? There's not a singular thing I can see there.

    --
    For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
  7. Obligatory XKCD by Anonymous Coward · · Score: 3, Funny

    "I just had an awesome idea. Suppose the entire observable universe exists as a 3d brane on the edge of a 4 dimensional black hole."

    "Okay. What would that imply?"

    "I dunno."

  8. That's easy for you to say .. by codeusirae · · Score: 3, Funny

    ".. we happen to live in the causal future of the classical big bang singularity .. we outline a novel mechanism through which any thermal atmosphere for the brane, with comoving temperature of 20% of the 5D Planck mass can induce scale-invariant primordial curvature perturbations on the brane, circumventing the need for a separate process (such as cosmic inflation) to explain current cosmological observations ..."

  9. Re:Get out the bong by gl4ss · · Score: 5, Insightful

    ICP could be playing CH, it's his head, his rules.

    but if the clown posse is playing cypress hill songs in his head he might not need another hit for a while...

    --
    world was created 5 seconds before this post as it is.
  10. Don't get too confused by Anonymous Coward · · Score: 3, Informative

    The article is about string theory (I think more properly called "M-Theory" these days but not sure). It is the outcome of a lot of very crazy math and complicated equations that are hard to visualize.

    But, what this theory sorely lacks is evidence. By which I mean any evidence at all. It is popular in the physics world because it can resolve the discrepancies between quantum mechanics (for which there is quite a lot of solid, verifiable evidence) and general relativity (for which there is also quite a lot of evidence). Everyone wants to be aboard THAT train...so it gets a lot of attention... ...but it still lacks evidence. And without the evidence it is just so much hot air.

    So, don't lose any sleep over this one. The proof just isn't there.

  11. Re:We live inside a black hole? by mysidia · · Score: 3, Insightful

    Is it possible to enter the universe inside a black hole?

    Arguably... to enter the universe inside a blackhole; you have only to enter the event horizon, and merge with it.

    Once you merge with the event horizon; you can never leave the black hole or ever be visible to an outside observer again. Also; you will get squashed into 2 dimensions, and your particles will be scrambled ---- so although the matter that comprises you merges with the universe inside the blackhole: your physical body does not survive.

    Physicists cannot say what happens to your immortal soul --- whether it escapes the pull; or whether it too becomes entrapped in the event horizon of that featureless pocket universe for the rest of eternity.

  12. the math that proves it by slashmydots · · Score: 3, Insightful

    There's actually some math that proves this theory.
    Baseless claim/theory with zero evidence + inability for anyone anywhere to disprove it = book deal + huge $$$ grant + discovery channel special

    You know, like the theory that the entire universe is a gigantic is a simulation similar to the matrix. There was a very elaborate, college-funded experiment to test that actually (as seen on slashdot)

  13. The trouble with mathematical models by Tony+Isaac · · Score: 4, Interesting

    This is an illustration of where mathematical models can run amok.

    Every kind of model has its limits. Bohr, for example, envisioned atoms as a nucleus of positively charged protons and neutral neutrons, with orbiting electrons. The model works well because it's something people can grasp. But the model has its limits, and there are many aspects of quantum behavior that cannot be explained by the Bohr model. The model is still useful because it does lead to many accurate scientific predictions.

    A newer mathematical model, quantum mechanics, seeks to be even more accurate in its predictions than Bohr's model. It succeeded in many ways, and like the Bohr model, has led to many interesting discoveries. But it too has its limits.

    In pure mathematics, exceeding three dimensions is effortless. Calculations involving four or more dimensions can easily be solved. But just because the mathematical model can do it, doesn't mean that the physical reality it attempts to model, can also do it. A model is designed to represent reality, but it is not itself reality. I suspect that all such mathematical models of the universe, which point to other dimensions, will eventually be shown to be purely mathematical.

    1. Re:The trouble with mathematical models by jamesh · · Score: 3, Funny

      This is an illustration of where mathematical models can run amok.

      My favourite is:
      There are 4 people in a room, then 7 people leave. How many people have to enter the room for it to be empty again?

    2. Re:The trouble with mathematical models by oldhack · · Score: 4, Informative

      I don't know, but maybe they should have used condom.

      --
      Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
  14. Trying to visualize this ... by triclipse · · Score: 3, Funny

    ... hurts my brane.

    --
    No Inflation Taxation without Representation
  15. Several errors. by rjh · · Score: 5, Informative

    In no particular order:

    1. Hawking proved... No, he did not. Hawking has a mathematical description that's consistent with quantum mechanics and general relativity, but that doesn't mean the universe actually works this way. There have been a large number of highly promising theoretical constructs that have never been observed in reality and are believed to not exist. Hawking radiation may be one of them. Most physicists believe Hawking radiation exists and is a real phenomena, but it has never been observed in reality. (We have, however, observed analogues to Hawking radiation from acoustic 'black holes'.)

    2. Highly charged particles are emitted at the poles of a black hole... No, they are not. Those jets are made of matter that was about to cross the event horizon until they suddenly and violently thought better of it. The area around an accreting black hole is perhaps the most violent spot imaginable in the universe; it should be no surprise whatsoever that once something has gone around the accretion disc a few million times it would have enough kinetic energy to go like hell off in another direction as soon as it collides with another particle. One of the billiard-balls rockets across the event horizon and the other uses its kinetic energy to escape from the accretion disc. (This is handwaving a lot of astrophysics, but is basically accurate.)

    3. the black hole itself is also rotating at the speed of light... No, it is not. Black holes have to obey the cosmic speed limit just like everything else. Also, not all black holes possess angular momentum. General relativity gives perfectly satisfactory predictions for stationary black holes.

    4. The information, that is the quantum state, of mass and energy that is eaten by a blackhole is later ejected as what could be termed high energy 'noise'; x-rays and gamma rays. Not in the slightest. Hawking radiation is about the longest-wavelength (which means lowest-energy) stuff in the universe. The reason for this is really simple: although it started off as unbelievably energetic, it had to expend virtually all of its energy escaping from where it was created a nanometer beyond the event horizon.

    No offense, but you need to sit down with a good book on general relativity. (I like Sean Carroll's Spacetime and Geometry. YMMV.)