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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."

6 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.

  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.
  3. 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).

  4. 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.