Black holes are weird. Really weird. You just won’t believe how vastly hugely mindbogglingly weird they are.
Not convinced? Try this one: Certain black holes are so weird they might actually obliterate your past if you journey into one.
UC Berkeley mathematician Dr. Peter Hintz is especially troubled by this, as his calculations have shown that a certain type of theoretical black hole, of sufficient size, might allow an observer to safely travel through its horizon, entering a wonderland where right is up, left is down, and there are infinite possible futures.
And he has no clue what would happen after that.
This is where the fun begins
According to Berkeley News, a Reissner-Nordström-de Sitter black hole is a “standard, non-rotating black hole with an electrical charge.” We’re not likely to find one of these in the natural world, as black holes tend to eat everything they can and ultimately become neutral. However, Hintz’s calculations show they are a possibility.
This type of black hole also has what’s called a Cauchy horizon beyond its event horizon, and this would typically see the end to anything that crosses into it, especially a human.
“In effect, all the energy the black hole sees over the lifetime of the universe hits the Cauchy horizon at the same time, blasting into oblivion any observer who gets that far.”
Sounds bad. But according to Hintz, an expanding universe means this might not actually be the case. Only energy within the “observable horizon” of the black hole could ever reach it, given that energy cannot travel faster than light. Because of this, Hintz has shown it’s possible you wouldn’t be annihilated in the Cauchy horizon of a Reissner-Nordström-de Sitter black hole.
In fact, if the charged black hole is large enough (supermassive), an observer could theoretically cross its event horizon without any issue at all. Then, it’s on to the Cauchy horizon. If Hintz is right and that doesn’t destroy the observer, the world they encounter would be something along the lines of incomprehensible.
Determinism would fail, the observer’s past would cease to exist, and that’s when things get really, really weird.
“…one can avoid the central singularity altogether and live forever in a universe unknown.”
Hintz likens this to Alice venturing down the rabbit hole and entering an absurd realm where nothing makes sense, and the past no longer determines the future.
“If the black hole parameters are sufficiently extremal,” he says, “It could be that she can just cross the Cauchy horizon, survives that and reaches a region of the universe where knowing the complete initial state of the star, she will not be able to say what is going to happen. It is no longer uniquely determined by full knowledge of the initial conditions. That is why it’s very troublesome.”
The good news (I guess), as previously mentioned, is that these black holes are “unlikely to exist” in the real world, and are only a possibility according to relativity. It’s all in the math. But, apparently, Hintz also says that rotating black holes would likely act in a similar fashion.
In conclusion, the universe is a mess.
Hintz’s study can be found in Physical Review Letters.