Physics

Fifth-dimensional black hole could cause general relativity to break down

A ring-shaped black hole in a universe with at least five dimensions could break Einstein's theory of general relativity
A ring-shaped black hole in a universe with at least five dimensions could break Einstein's theory of general relativity
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A ring-shaped black hole in a universe with at least five dimensions could break Einstein's theory of general relativity
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A ring-shaped black hole in a universe with at least five dimensions could break Einstein's theory of general relativity
Simulated 3D view of a five dimensional black hole
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Simulated 3D view of a five dimensional black hole

We like to think of the physical universe as being governed by immutable laws, but maybe they're not quite as concrete as we imagine. A team of physicists at the University of Cambridge have run computer simulations that show that a five-dimensional, ring-shaped black hole could violate Einstein's general theory of relativity by creating a naked singularity, which would result in the equations behind the theory breaking down.

Though only about a century old, the theory of general relativity is key to understanding the very basic nature of the universe. It tells us that gravity is a distortion by matter of the space-time continuum. It allows us to estimate the age of the universe and its structure. It even let's us use GPS navigation systems with confidence.

However, general relativity doesn't apply everywhere. For example, in a black hole space and time collapse in on one another in a singularity that has infinite mass and infinite gravity. It's a place where space, time, matter, and the very laws of physics cease to be and where anything that enters is trapped forever – if it exists at all.

It's the sort of things that gives physicists cold sweats at night, but they take comfort in the fact that, technically, black holes don't exist in our universe. Instead, they're edited out of our world by a kind of cosmic censorship. In other words, though a black hole may exist from the point of view of an omniscient being and be generally accepted by scientists, we can't actually prove they exist because we can't observe them.

This is because a black hole is hidden behind what is called the event horizon. This is an area around the black hole where the pull of gravity is so strong that light itself cannot escape. This means that the black hole is effectively cut off from our universe as nothing, not even light, can escape, no data can go from it to our universe. It is pinched off from reality. This "cosmic censorship" means that, even though the laws of physics break down inside a black hole, it doesn't matter because it's hidden behind the event horizon, so for all practical purposes the black hole doesn't exist.

That's comforting except for the fact that general relativity doesn't say how many dimensions there are. Our space-time continuum is made up of four dimensions (height, breadth, width, and time). But string theory and other branches of theoretical physics say that there could be as many as 11 dimensions with some existing on very large, even cosmic scales and others on the quantum scale, which we can only perceive indirectly.

What the Cambridge team and scientists from Queen Mary University of London did was to use the COSMOS supercomputer to simulate how a black hole that exists in a five-dimensional universe would behave. Such simulated extra-dimensional black holes have been known of theoretically since 2002, but the team says that this is the first time one has been simulated using a supercomputer to learn its dynamics.

What they found was that in most cases, the black hole collapses into a sphere surrounded by an event horizon as it does in our universe. However, in some cases it forms a thin black ring. This ring creates bulges connected by strings, which grow thinner. Eventually, these strings pinch off and the bulges become mini black holes, but without event horizons. These "naked singularities" would be places where general relativity breaks down, yet would be visible to the rest of the universe.

Simulated 3D view of a five dimensional black hole
Simulated 3D view of a five dimensional black hole

This is what is known as a very bad thing because it would represent an object that has collapsed to an infinite density, a state which causes the laws of physics to break down, yet still exists. It would mean that the universe is no longer predictable because physics is like a carefully woven tapestry. If one law falls, so do all the others. Indeed, Einstein's great accomplishment wasn't to show that Newton was wrong, but that his classical model of the universe was a special case inside of a new model that Einstein formulated.

A naked singularity would be like taking the whole of physics and drop kicking it. We would no longer have a general explanation for how reality works. It would have physicists running back to the drawing board to find something else, such as quantum gravity, that can explain the universe.

"The better we get at simulating Einstein's theory of gravity in higher dimensions, the easier it will be for us to help with advancing new computational techniques – we're pushing the limits of what you can do on a computer when it comes to Einstein's theory," says PhD student Saran Tunyasuvunakool. "But if cosmic censorship doesn't hold in higher dimensions, then maybe we need to look at what's so special about a four-dimensional universe that means it does hold."

The study results were published in Physical Review Letters.

Source: University of Cambridge

22 comments
TomBellinson
My understanding is that Hawking has demonstrated that there are particles that do escape from black holes, thus making the underlying premise of this story inaccurate.
stewged
so...something we created in our imagination can break the laws of physics? Awesome!
chec
Yes, TomBellinson has brought up a good point, and these escaping particles are called Hawking Radiation. This causes even black holes to eventually evaporate, given enough time! So this does undermine the whole concept of black holes not existing, which is inaccurate, because they can be detected by this radiation.
hgdorsey
It is time to move beyond Einstein's theory which has been disproved in so many experiments. Take torsion waves for example, which move at least 9 orders of magnitude faster than the speed of light if not instantaneously. Then there is quantum entanglement, which cannot be explained with General relativity. The experimental unification of electromagnetism and gravity was discovered in the 1920s by Thomas Townsend Brown, yet university physics courses are strangely silent on that fact. Try reading "The Covert Colonization of Our Solar System" to discover what is going on in the field of "black science".
attoman
Mathematics arises from human imagination. Used and interpreted wisely it can describe the world in useful ways. However some results are meaningless when checked against measured reality. No list of meaningless results could fail to include the singularity, a mass in a point. Despite the claims of the Cambridge "scholars", and using the heaviest thing known to date - the Higgs particle- it still is not a point-that is a thing infinitely small. Even the very smallest thing we can measure the neutrino and electron/positron have measurable size or wavelength.
Bob Flint
We therefore have very few facts, and based on this know next to nothing...and everything up to this moment is ancient history as we try to stare and speculate into the past, to only imagine what the future holds, in humanities fleeting moment in relative time.
Carl23
"In other words, though a black hole may exist from the point of view of an omniscient being and be generally accepted by scientists, we can't actually prove they exist because we can't observe them." Actually there are plenty of things we can't "see", but we know they exist because of the clear effect they have on nearby systems. In the case of black holes, their gravitational impact is beyond doubt.
Douglas Bennett Rogers
The fifth dimension provides room for a real probability array, so there is no need for instantaneous communication.
H Robinson
They've been watching to many reruns of Fring the sci-fi Tv show.
Lbrewer42
From what I understand, Bugs Bunny already has been proven capable of breaking many of the fundamental laws of physics. But, or course, his type of fiction was not first produced using a computer model. So now that we can say the fantasy is computer generated it makes the news? Where is the ACTUAL intellect in this? It has taken some upper level math and a computer to make speculations on a fantasy item. This is much like Mike and Sully of Monsters, Inc. So yes, not everyone can be Pixar in their own home, but at least Mike and Sulley entertained the masses and made millions to produce more entertainment for the masses. This 5th dimensional black hole story does what? This is the type of thing people should not be being paid to do, but it could be fun as a hobby. This is the problem with modern so-called science. We can all go on computer aided fantasy trips exploring the unknown - and it can be fun. But the problem is the general populace would look at the title and think something legitimate to our world - not imaginations - has been show here. I think I 'll go watch MIke and Sulley again.