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

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."

Comments

Predictive power

[Tough Love]

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.

Re:Predictive power

[NotInHere]

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.

Re:Predictive power

[dissy]

I wonder if whomever wrote that realized the double-edged nature of their comment or not.

"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."

In other words:

"This research we are asking you for more grant money to continue studying, we have now demonstrated is completely and thoroughly proven physically impossible by all known laws of physics!"

Re:Predictive power

[Anonymous Coward]

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.

Re:Predictive power

[iggymanz]

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

Re: Predictive power

[Pikoro]

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

Re:Predictive power

[Crashmarik]

It's not about predictive power it's about describing the system and providing insight into what is happening. Aristotelian mechanics still have limited predictive power as well but you wouldn't use them when thinking about extending physics.

Re: Predictive power

[pdavisgenoa]

The cake is a lie.

Re: Predictive power

[PopeRatzo]

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.

Re:Predictive power

[Roger W Moore]

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

You would not conclude that because of length contraction: you would conclude that Andromeda was a lot closer. Newtonian mechanics also predates relativity. Therefore when relativity was discovered it replaced Newtonian mechanics which essentially became the low energy approximation to relativity. So in no sense did Newtonian mechanics "discard" a possibility allowed by relativity: once relativity was confirmed Newtonian mechanics was relegated to a low energy approximation of relativity and was no longer regarded as a fundamental description of the universe.

This last part is a key point in physics. The data supporting relativity are overwhelming: special relativity is the most accurately tested theory science has ever come up with. Any replacement of relativity by something new will almost certainly mean that the new theory can only significantly differ under situations we have never tested relativity under. As such it is very unlikely to introduce possibilities which we have already discarded and far more likely to introduce possibilities we have never even thought of. In fact you example is a good case in point: Andromeda was classed a nebula before relativity was discovered and our modern understanding of an expanding universe filled with galaxies requires relativity to describe it. Hence we would never have even conceived of a trip to a distant galaxy without relativity.

Re: Predictive power

[Rei]

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?

Re:Predictive power

[reboot246]

Right. A much better one would be a sense of humor. I've never met a humorless person who could be considered intelligent. I've known lots of smart people with no sense of humor, and even more uneducated intelligent people who had a keen sense of humor.

Re:Predictive power

[BitZtream]

When your job is to sit around and make up things to magically make some silly idea you have 'fit' the real world, this is what happens.

You have a bunch of people who literally sit around and invent new ways of doing math that make absolutely no real sense, and have no really world evidence or proof to suggest they are even mildly accurate ... and they invented some new model that has no relationship to reality and in their made up universe, it breaks general relativity. Oh and its actually impossible to ever test it, so its not even really debatable.

You might as well go play video games or use startrek as your definitive 'how the universe really workse'

damn you, Planck

[turkeydance]

did you have to break everything?

Re:damn you, Planck

[fahrbot-bot]

did you have to break everything?

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

Bad interpretation

[Improv]

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.

Re:Bad interpretation

[justthinkit]

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.

"it would no longer have ANY predictive power"?

[jeffb (2.718)]

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.

Re:"it would no longer have ANY predictive power"?

[dgatwood]

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.

And yet if you get out of the way when there's a moon falling towards your head, they call you loony. Ba-dump bump.

Thanks. I'll be here all night.

"Break" is a stupid term

[Anonymous Coward]

If this is a situation General Relativity's rules can't work in, it doesn't mean GR is "broken" or that any of the predictions you can make with it magically stop working all of a sudden. GR doesn't work at extremely tiny scale where quantum mechanics applies; we don't say that it's broken, we just say that GR isn't applicable in that situation while we look for a theory that ties both together.

It's like, GR didn't "break" Newtonian physics either. You can still use Newtonian physics to do engineering calculations for most stuff here on Earth and it works fine. You just can't use it when you're talking about speeds approaching lightspeed or extremely large masses, or if you need more precision.

All theroies are just approximations of reality. New scientific discoveries just refine the theories. It doesn't mean you toss the old ones out altogether and it certainly doesn't mean that the old predictive rules somehow stop working in the old scenarios.

Mathematical self abuse

[Anonymous Coward]

So, using a model that doesn't fit general relativity, they created a simulation that doesn't match the model of general relativity. My model to break general relativity says intermediate vector bosons have a mass of 5 megagrams, and the speed of light is 16 megameters per hour. Unless there are multiple real world observations that conclude a ring shaped black hole is existent, they are simulating a fantasy universe, and should expand their model to show it is consistent with other observed physical traits of the known universe.

Re: Mathematical self abuse

[Maow]

It's not their fault, they are running their simulations on that same computer modeling software that says the Global Warning is real.

Spoken like a willfully and proudly ignorant troll.

How climate scientists test, test again, and use their simulation tools

Steve Easterbrook, a professor of computer science at the University of Toronto, has been studying climate models for several years. “I'd done a lot of research in the past studying the development of commercial and open source software systems, including four years with NASA studying the verification and validation processes used on their spacecraft flight control software,” he told Ars.

When Easterbrook started looking into the processes followed by climate modeling groups, he was surprised by what he found. “I expected to see a messy process, dominated by quick fixes and muddling through, as that's the typical practice in much small-scale scientific software. What I found instead was a community that takes very seriously the importance of rigorous testing, and which is already using most of the tools a modern software development company would use (version control, automated testing, bug tracking systems, a planned release cycle, etc.).”

“I was blown away by the testing process that every proposed change to the model has to go through,” Easterbrook wrote. “Basically, each change is set up like a scientific experiment, with a hypothesis describing the expected improvement in the simulation results. The old and new versions of the code are then treated as the two experimental conditions. They are run on the same simulations, and the results are compared in detail to see if the hypothesis was correct. Only after convincing each other that the change really does offer an improvement is it accepted into the model baseline.”

But don't let reality get in the way of your anti-science jihad.

Time to confiscate chalk!

[TheRealHocusLocus]

This sounds so incredibly dangerous.
Are the computer models even safe?
I wonder if these equations are even safe for chalkboards.
If we manage to glimpse a 'naked singularity' Mother Nature will start locking the bathroom door.

Obligatory Cyriak

hardly a shocker

[ooloorie]

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.

Re:Nonsense

[khallow]

"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).

We invented a God

[Etherwalk]

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.

Re:Bot how do you get one

[Waffle Iron]

A 5d ring shaped black hole might be cool, but how does one get created?

It's actually a straightforward process: You start with a 6D cylindrical black hole, and then you cleave off an infinitesimally thin slice perpendicular to its axis of symmetry.

true albeit not fully

[aepervius]

Newtonian mechanic still hold, because at those level it is an excellent approximation and virtually indistinguishable if GR did not exists. Sure we could find an alternative to GR, but as pointed out GR has many prediction/evidence. Therefore the new theory could only be like Newtonian theory : is all those predicted situation, GR should still stay an excellent approximation and virtually the result indistinguishable to result obtained if that new theory was not present barring new complex situation where GR break down. That is possible but far more likely the model for ring blackhole sucks and something is wrong with them or even them existing.