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I’m thoroughly convinced that this is not an original idea of mine, but I probably heard it and half-misremembered it from some lecture or sci-fi story or something else. Or possibly in college, after something mind-bending was consumed. Anyway.
Let’s assume the Big Crunch is the way the universe is going to end. The expansion of space eventually stops, reverses, ends up collapsing into a huge black hole into which all the stuff of the universe (including us, since we are star stuff and all) is sucked. There is already a theory that says this could initiate another Big Bang, launching another universe which would itself then do the same thing and the universe might yo-yo back and forth forever, from Big Bang to expansion to contraction to Big Crunch to Big Bang again.
But here’s a slightly different thought: black holes deform space and time around them (and by the way, check out the gravitational lensing simulation at the black hole wikipedia page… so cool). In fact, at the center of a black hole you have a gravitational singularity, which is defined as a region where the curvature of spacetime becomes infinite, and all kinds of weirdness ensues. But in certain types of black holes it is hypothetically possible to use this weirdness to travel to a different spacetime by using the black hole as a “wormhole”. Very cool stuff, but purely theoretical and probably only ever achievable as individual particles, not something we would be able to actually, you know, use as humans.
But what if all black holes… scratch that, what if the single black hole singularity at the end of the Big Crunch, the voracious Jabba the Hole that has consumed all, is actually is one of these wormhole-types of holes, and instead of spitting intrepid explorers out all over the placetime, it actually only has ONE spacetime endpoint to which it connects: this very same Universe’s Big Bang event. So, a supermassive black hole, containing the entire physical contents of our universe, funnels all of that content into a single point in spacetime that happens to be in its own distant past… the moment/place of its own birth? Feeding it over time, mind you, from the perspective of us as observers, but feeding it all at once, in the single instant/location of the Big Bang, from the perspective of an observer at the other end of the wormhole. To us it looks like this black hole has been consuming matter over billions of years (and from our perspective it has), but the end point to which all the matter is fed is not across multiple points in spacetime: it’s one single point.
What I appreciate about this thought is that we have the concept of the Big Bang/Big Crunch yo-yo, but instead of an infinite number of universes being created sequentially (for whatever the meaning of that word is when spacetime is created at the point of the Big Bang), you only have one universe, continuously creating and consuming itself at the same… well, “time” is the wrong word. So the causality problem of “what came before the Big Bang?” (so beloved by people attempting to insert a god into the picture) goes away: what came “before” the Big Bang was the same Klein bottle of a universe, consuming itself to be reborn. The universe’s history then has the same curved shape as its physical existence, where you can travel for a very long time in the same direction and end up in the same place you started (and vice versa). The destructive, all-consuming process that we theorize and observe in black holes today, is actually one side of a fiber-optic lens whose other end terminates billions of years ago in a single point, lather rinse repeat.
So technically, I guess if you look deep enough into this black hole, you would see the beginning of the entire universe that contains the black hole you are looking into. Gaze into the abyss, and the abyss gazes into the back of your own head.
A fun thought experiment, and I know little enough about the implications of black holes and wormholes to know that a theoretical quantum physicist can probably poke an Avogadro’s number-worth of holes into it. But in the short term, I’m thoroughly convinced I’m half-remembering this from somewhere or someone or something I’ve seen or heard before. If I were a New Age nutcase I’d say I’m probably experiencing the deja vu of me experiencing myself remembering myself in this infinite loop of a universe, but then I’d have to conclude that my head is full of rocks.
Does this sound familiar to anyone?
[Edited 10/5/2011 to tack on some comments from a G+ discussion of the above]
I think this whole thought came from the fact that when you have a black hole-caused wormhole, it spits out whatever traveled through it into a different point in spacetime. But in the case of the black hole singularity, there is no other space to spit things out to, so what becomes the only variable there is time. It’s at that point possible that over enough time (from the singularity’s perspective) all particles eventually travel through wormholes that end up at a different point in time in the same universe.
Since that point in time might be variable, sometimes the particles seem to appear “out of nowhere” randomly throughout the history of the universe. Who knows, the end point of the wormhole could actually be TWO end points traveling in opposite directions with regards to time, so what we see is a particle and its anti-particle appearing and then annihilating each other, but they are really just the same particle encountering itself while traveling in opposite time directions. Eventually (again, at random) they appear at the moment of the Big Bang, and just as at the event horizon of the black hole you have radiation from one of the particle/anti-particle pair escaping the hole’s gravitational pull and the other being absorbed, at the Big Bang you have the concentrated output of all of those absorbed particles. Ignore most of this paragraph, though, I’m just throwing words around.
I don’t know, I’m not trying to get into Time Cube territory here, but it seemed a plausible (albeit somewhat far out) response to the causality problem: it’s really a response to a religious argument more than anything that I actually think has a high scientific probability of having happened. But if what came “before” the Big Bang was the very same universe itself, then the argument that says “What caused the Big Bang? A-ha! You don’t know, therefore it must be God!” gets a bit of a mind-blowing (and to me, rather pleasing) answer. Do I believe it actually happened? Probably not, but the explanation tickles my endorphin producers in the same way a well-thought out time travel sci fi story does.