A recent effort to do away with singularities — the infinitely dense points believed to be at the heart of black holes — has reignited debate among physicists. Now, a team led by Robie Hennigar of Durham University suggests a new model that has gravity undergoing a different type of behaviour at the extreme limits and replaces the singularity of the black hole with a small, compact core that always remains static and very strongly curved. The modified Einstein’s equations, representing general relativity, have been generalised, and higher-dimensional effects are incorporated. Although the discoveries garnered attention for perhaps explaining a fundamental cosmic paradox, critics have mentioned that the model has no experimental underpinning and is based on overly speculative mathematical concepts.

Critics Challenge 5D Gravity Theory Aimed at Replacing Black Hole Singularities Without Evidence

As per a Space.com report, Hennigar’s theory introduces modified gravity in five dimensions, which some scientists argue goes beyond what current observations allow. Nikodem Poplawski, a physicist at the University of New Haven in Connecticut, pointed out three things that stood out to him: there is no experimental evidence for extra dimensions, the current study only assumes a static black hole interior, and the model uses an infinite series of mathematical terms that don’t have any physical justification.

Poplawski stressed that changing general relativity without experimental evidence makes the model more of a theoretical curiosity than a real physical theory. He also highlighted the fact that black hole interiors, according to conventional field equations, should not be static. He further stated that just changing equations to get rid of singularities doesn’t fix the physics behind them; it can only hide it behind complicated mathematics.

Hennigar’s team used modified gravity to deal with the singularity, but scientists say that general relativity and quantum mechanics should be combined. The problems with string theory, however, include features such as dimensions that have never been fixed and supersymmetric particles that have never been detected.

Poplawski concurs that investigating mathematics may be fruitful and also hopes that bold ideas, such as the notion that black holes spawn new universes, may prove profitable in the future.