How White Holes Work | Unveiled

How White Holes Work

Black holes are among the strangest structures in all of space; vast and mysterious with powerful singularities where the rules of physics fall apart. It’s thought that they could hold the secrets to life, the universe and everything... And yet, their currently hypothetical counterparts are perhaps even stranger still!

This is Unveiled, and today we’re answering the extraordinary question; How do white holes work?

Where black holes are objects with gravity so strong that nothing, not even light, can escape them… white holes are theorised as objects so repulsive that nothing can ever enter; the two are the reverse of one another. This also means that rather than pulling matter in and crushing it down, a white hole would spit matter out at impossible speeds.

Some speculate that black and white holes could actually be two different stages in the lifetime of the same object, however. There are problems with this - one of the biggest being that nobody understands how a black hole could spontaneously or even slowly transform into its opposite - but it’s an idea which also solves certain problems too, primarily the black hole information paradox. Since the first law of thermodynamics says that energy cannot be created or destroyed, the fate of the matter that becomes part of the black hole’s singularity has long been one of the greatest mysteries of space. Because, without breaking the laws of physics, where does all of it go? If a black hole really did (somehow) transform into a white hole, then its matter would simply be ejected back out, returning to the universe once more.

There are other ideas, too, about how the existence of white holes could solve this same issue. If black holes don’t truly morph into their counterpart, they could be what sits on the other side of an incredible tunnel through space and time. It’s famously theorised that black holes could be gateways to other parts of the universe or even new universes entirely… and, if that’s true, a white hole could be at the “other end” of that tunnel; it’d be what you’d find yourself in were you to somehow travel through a black hole and not die. Unfortunately, thanks to the gravity and the radiation and the fact that any such path would probably instantly collapse as soon as you entered into it… it’s all but impossible to test the idea out.

Nevertheless, when thought of in this way, white holes provide part of the answer to what Einstein-Rosen bridges, or “wormholes”, would look like if they exist. Like white holes in themselves, wormholes also make sense mathematically, but we’ve yet to prove or observe them. The problem is that both wormholes and white holes are potentially very short-lived, especially if - as many believe - white holes were to disappear once they eject all the mass collected in their core. If that’s the case, even if a white hole showed up just 100 lightyears away, it would still take us 100 years to know about it, by which point that same white hole could well have disappeared. It’s a complex cosmological conundrum.

And yet, it’s possible that we could already have evidence supporting the existence of white holes. Gamma-Ray Burst 060614 was detected in 2006, with some suggesting that it could have originated from a white hole. Usually, we think gamma-rays like this come from distant supernovae… but we couldn’t detect a supernova to explain the origin of this particular burst. It’s an especially niche theory, but if it did turn out to be true it would mean that we’ve had proof that white holes exist for years just without understanding what we’ve been looking at.

Elsewhere, theories about white holes offer answers to some of our other greatest mysteries. Dark matter and dark energy make up the majority of everything in the universe; only around 5% of everything is observable matter, which includes all the stars, galaxies, planets, asteroids, moons, creatures, and so on. Outside of that, around a quarter of everything is dark matter, and the rest is dark energy. We only know that dark matter exists because we can observe its effects on normal matter… which is all well and good, but where does it actually come from? One potential answer first put forward by physicists Carlo Rovelli and Francesca Vidotto: white holes… if white holes are actually very, very small - as in subatomic. They could then bounce off the other particles we understand (like protons) because of their repulsive nature, all the while spitting out dark matter and therefore (indirectly) shaping the entire universe we live in.

But the very existence of white holes is still an incredibly contentious point, with some scientists arguing that they’re impossible. One of the biggest marks against them is that a white hole would have to have a “naked singularity”, which is a singularity that’s not surrounded by an event horizon and is, therefore, visible. Standard singularities are bizarre and complex enough, mostly because we may never observe what one looks like seeing as not even light can escape a black hole… But naked singularities take it up a notch, and while one side argues that they’re also physically possible, another says that they’re not. There’s even the “cosmic censorship hypothesis” - a theory that naked singularities can’t exist because of physical principles we don’t yet understand. If they were to exist then they’d also go against determinism, in some ways forcing us to accept that we don’t actually understand anything about the universe we live in. One thing that is certain right now… even if naked singularities are real, we’ve never identified them.

Another important problem with the prospect of white holes is that they would, theoretically, decrease entropy… But we know (thanks to the second law of thermodynamics) that entropy (the measurement of useful - or non-useful -energy) always increases over time, across the universe. Perhaps there’s a kind of cosmological balancing act going on between them and black holes - which we know increase entropy - but for now, the general effect of white holes on the cosmos is something we can’t account for.

But, finally, for some, one way to tie up all the loose ends is to pitch white holes not as things that exist inside our universe… but as something that started it all off! There are now countless theories on what “the Big Bang” was, what it looked like and how it happened… but imagine it as a white hole, powerful enough to kick-start the universal expansion that’s still happening today, and the origin of the cosmos gains yet another layer; another alternative possibility for how everything began. Should that especially hypothetical white hole ever close, then what happens next is another question entirely!

But regardless, these much-speculated, celestial bodies throw up plenty of puzzles. They’re hypothetical, repulsive structures that could range from being smaller than an atom to so huge that just one of them could create the entire universe. And that’s how white holes work.