Black holes are rather weird and mysterious – but they could get even more puzzling. For the first time, scientists have demonstrated that black holes in 5D could defy the prevailing laws of physics and our basic understanding of the universe.
Researchers from the University of Cambridge and Queen Mary University of London in the UK showed that a black hole in a five-dimensional world could disprove Einstein’s general theory of relativity, a foundational law of physics. This means that 5D black holes would contain such intense gravity that the laws of modern physics as we know it would break down.
According to the simulation, a five-dimensional universe would have black holes that are akin to very thin rings instead of holes, giving rise to a series of “bulges” that turn thinner over time. The strings connecting these bulges eventually turn so thin that they form mini black holes.
These so-called “black rings” were first discussed in 2002, but it is only now with the aid of supercomputers – like the COSMOS supercomputer – that they were simulated successfully.
Should 5D black holes form, they would give rise to “naked singularity” since they hypothetically consist of rings of highly intensive gravity. The resulting event is equally mysterious, except that it would show that the laws of general relativity is no longer applicable.
The general theory of relativity guides what humans know so far about gravity, from estimates of the age of the stars in the universe to the GPS signals helping in navigation. In a nutshell, it dictates that matter is warping surrounding spacetime, with gravity as the effect of such warp.
It has been 100 years since the theory was first proposed, and it has so far passed each test thrown its way. The phenomenon of singularities, however, remains one of its primary limitations.
In a singularity, gravity is very intense that time, space, and laws of modern physics break down. According to the general relativity, these events exist right smack in the middle of black holes and are surrounded by an event horizon or the so-called “point of no return,” where the pull of gravity turns so strong that escape cannot be observed from outside.
Study author Dr. Markus Kunesch from Cambridge explains that singularities are not a source of trouble – meaning the theory still holds – as long as they stay hidden behind an event horizon.
“[T]he 'cosmic censorship conjecture' says that this is always the case,” Kunesch says. He adds that scientists can safely predict the future outside of the black hole phenomenon as long as this conjecture, which is widely accepted as true in humans’ four-dimensional universe, remains valid.
What if a singularity outside of an event horizon existed, which physicists hypothesized might be existing in greater dimensions?
It would be visible and a state where an object collapses to an endless density would emerge, causing general relativity to fall apart and remove its “predictive power” or strength as a stand-alone theory for explaining the universe, says co-author Saran Tunyasuvunakool.
This emerges as a relevant issue when one considers that physicists have proposed the universe to be consisted of as many as 11 dimensions. Humans can only perceive three, with the existence of extra dimensions only inferred from high-energy experiments including the Large Hadron Collider.
The team has reached the limits of what the COSMOS supercomputer can simulate, with new techniques and computer code required to handle extreme shapes that a black ring forms into. But they seek to know what elements in a four-dimensional universe could make naked singularity impossible – and the theory of general relativity correct.
The findings were published in the journal Physical Review Letters.
