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Five-Dimensional Black Hole Could 'Break' General Relativity (sciencealert.com)

Posted by BeauHD on from the theory-of-gravity dept.

The researchers, from the University of Cambridge and Queen Mary University of London, have successfully simulated a black hole shaped like a very thin ring, which gives rise to a series of 'bulges' connected by strings that become thinner over time. Ring-shaped black holes were 'discovered' by theoretical physicists in 2002, but this is the first time that their dynamics have been successfully simulated using supercomputers. Should this type of black hole form, it would lead to the appearance of a 'naked singularity', which would cause the equations behind general relativity to break down. "If naked singularities exist, general relativity breaks down," said co-author Saran Tunyasuvunakool, also a PhD student from DAMTP. "And if general relativity breaks down, it would throw everything upside down, because it would no longer have any predictive power -- it could no longer be considered as a standalone theory to explain the universe."

14 of 146 comments (clear)

  1. Predictive power by Tough+Love · · Score: 5, Insightful

    I wonder where the rubbish claims about predictive power came from. General Relativity has already made many predictions, subsequently verified. Those won't suddenly vanish.

    --
    When all you have is a hammer, every problem starts to look like a thumb.
    1. Re:Predictive power by NotInHere · · Score: 5, Insightful

      Newtonian mechanics made lots of preditions too, and applied to a small enough frame newtonian mechanics hold as well. Probably its similar for general relativity. Otherwise we'd have found the "theory that explains it all". And that'd be quite cool on one hand, but quite un-cool at the other hand, because now there is nothing anymore we can discover.

    2. Re:Predictive power by Anonymous Coward · · Score: 5, Informative

      I think the point Tough Love is making is that Newtonian mechanics still has exactly as much predictive power as it always had. Relativity would as well. But it would indicate we need to generate a theory that could predict what neither Newtonian nor Relativistic mechanics could predict.

      A counterpoint, though, is that Newtonian mechanics could have predicted certain impossibilities. For instance, you might conclude based on Newtonian mechanics that a human, aged 20, with a lifespan of 100 years and no cryonics, starting from Earth, could not see the Andromeda galaxy without travelling at least ~3*10^20 meters per second (distance to Andromeda Galaxy / 80 years). General relativity tells us that you can't go more than ~3*10^8 meters per second, the speed of light, which is almost exactly one trillionth of the speed we need to get to Andromeda. Yet, famously, you can get to the Andromeda galaxy in a spaceship with a constant rate of acceleration g (itself an *incredible* feat), over the course of a "mere" 28 years. If you had travelled to the Andromeda Galaxy and back (you found a discarded Alien spacecraft), you might conclude that you had travelled at a speed well in excess of the speed of light. So Newtonian mechanics discarded a possibility that General Relativity allowed, and General Relativity discarded a possibility that Newtonian mechanics disallowed, and we know that GR wins over Newton when they conflict. Perhaps "Trans-Relativity" could introduce possibilities that we'd previously discarded, forcing us to re-evaluate some old data.

    3. Re:Predictive power by iggymanz · · Score: 4, Interesting

      but remember the scary thing that happened when newtonian mechanics were found to be inaccurate and incomplete, all the buildings and bridges and engines we've designed that used them fell apart as the predictive power evaporated.

      oh wait I'm full of shit

    4. Re: Predictive power by Pikoro · · Score: 4, Funny

      It won't be finished until we can extrapolate the entire universe from a piece of fairy cake.

      --
      "Freedom in the USA is not the ability to do what you want. It is the ability to stop others from doing what THEY want"
    5. Re: Predictive power by PopeRatzo · · Score: 4, Funny

      It won't be finished until we can extrapolate the entire universe from a piece of fairy cake.

      I fail to see the significance of the cake's sexual orientation.

      --
      You are welcome on my lawn.
    6. Re: Predictive power by Rei · · Score: 4, Interesting

      Exactly. It's perfectly normal that our theories are built around the limits of our knowledge. A theory may work great until we start gathering new data in new ways which shows that there are problems in it... and then the theory needs to be expanded. That doesn't mean that the previous theory was wrong - just limited.

      Honestly, there's enough problems with event horizons and singularities that I really think it's about time that we accept that they may well just not exist. We have a known force of the universe, inflation, that when the universe was packed into a very energy dense state led to the dilation of space until the universe reached a less energy-dense state. Why should we assume that this is something only applicable to the Big Bang, rather than a general rule of the universe? When you apply a dilation-driven inflation gravity to the environment of a black hole, suddenly singularities and event horizons disappear. A black hole is often described as a waterfall of spacetime rushing in; inflation is like a flood of spacetime rushing out. Infalling particles are shifted to a tangential path; all of the energy of the black hole exists at the event horizon in a quasi-2d state. In such a scenario, black holes are - from an infinite-observer's perspective - basically nothing more than a frozen store of spacetime, ever so slowly leaking out, until - unthinkably long in the future, when they sit all alone in an empty void - they catastrophically explode in an inflationary flood of energy from which new matter can ultimately condense. Miniature versions of the Big Bang itself.

      No naked singularities. No information paradox. No firewall. Explanatory power for the Big Bang. Why isn't this a theoretical route worth pursuing more?

      --
      The War of 1812... the good 'ol days when the federal government actually tried to save New Orleans.
  2. Bad interpretation by Improv · · Score: 5, Interesting

    Even if the facts are good and the theory is right, the analysis quoted is broken. A theory doesn't need to be able to explain the entire universe to have *some* predictive power. It's also weird to say that the equations "break down" in such an unqualified sense; what is meant (presumably) is that there are conditions where those equations can't be evaluated and likely don't apply.

    --
    For every problem, there is at least one solution that is simple, neat, and wrong.
    1. Re:Bad interpretation by justthinkit · · Score: 4, Interesting

      I agree with your points. Einstein's relativities do not have to work everywhere to be useful in many places and ways. And a Black Hole could easily be an edge case where laws/assumptions are incomplete/not applicable. I said the same thing (here) in 2014.

      In addition, since when is a 5-D simulation related to relativity? Einstein never went beyond 3+1. So this article/the simulation team's conclusion is insulting to Einstein's work but otherwise not related to it.

      --
      I come here for the love
  3. "it would no longer have ANY predictive power"? by jeffb+(2.718) · · Score: 4, Insightful

    By the same token, Newton's law of gravitation has clearly lost ALL predictive power, since it breaks down in the relativistic realm. So feel free not to get out of the way next time there's an anvil falling toward your head.

  4. hardly a shocker by ooloorie · · Score: 4, Insightful

    And if general relativity breaks down, it would throw everything upside down, because it would no longer have any predictive power -- it could no longer be considered as a standalone theory to explain the universe."

    This is hardly a shocker, since general relativity and quantum mechanics have not been successfully unified, and since general relativity simply cannot work at the quantum level as it is.

  5. Re:damn you, Planck by fahrbot-bot · · Score: 4, Funny

    did you have to break everything?

    I dunno. Seems he's been pretty constant ...

    --
    It must have been something you assimilated. . . .
  6. Re:Nonsense by khallow · · Score: 5, Interesting

    "physicists have successfully simulated what would happen to black holes in a five-dimensional world," That's all the further you have to read the article. The universe has either 4 or 10 dimensions if I remember the two theories correctly. It does not have 5 dimensions. This is science fiction/science fantasy.

    The point of the five dimensional black hole is that it might represent an actual thing combining normal general relativity and electromagnetism. The idea is that the fifth dimension becomes when approximated by our near-Newtonian world, the symmetry of electromagnetism.

    As I understand it, a key problem is that as a result of the model, one gets a scalar (number valued) field left over which we haven't observed yet (though at one time, it was thought that the Pioneer spacecraft anomalies might be an indication of the field).

  7. We invented a God by Etherwalk · · Score: 5, Insightful

    Are we really hubristic enough to think we will ever have a theory that predicts and explains everything with 100% accuracy at all levels?

    We invented a God who created the universe and pretended he looked like us. Yes, we have more than enough hubris.