Black Holes - What's on the other side? (1 Viewer)

[Jimmy Kilgour]

"Black holes-what's on the other side?"
Jimmy Hoffa and those two dudes that sang that Macarena song.

 

[BrianW]

According to one theory, all you have to do to see what’s on the other side of a black hole is to look around you. Everything you see – the planets, the stars, the galaxies, the whole Universe – could be on the other side of a black hole that exists in a completely different universe. And that universe is on the other side of a black hole in its parent universe, and so on. In turn, all the black holes in our Universe have universes on the other side of them, and their black holes have universes on the other sides of them, and… Well, you get the idea. There may be more universes than there are stars, or even protons, in our one Universe.

Of course, it’s just a theory. But it does answer a few nagging questions. What was the Universe like before the Big Bang? If it was a superdense particle that perhaps has always existed, then what suddenly caused it to explode into the Universe we see now? What could possibly cause a superdense particle that has always existed to suddenly destabilize and explode into a Universe? It’s anybody’s guess. The preferred notion is that the Universe didn’t exist at all before the Big Bang, in any form. But then what made it spontaneously arise and explode out of nothingness? The answer, according to this theory, is that the formation of a black hole in our parent universe caused a quantum hiccup that sparked our Big Bang and created our Universe. (There are other issues that make this theory compelling, but the most compelling aspect of the theory is the extent to which it joins quantum mechanics with Einstein’s gravitational theory within the event horizon. No other theory has made such great strides in this area.)

So with the triggering mechanism thought to be the formation of a black hole in another universe, the unattractive notion of our Universe spontaneously and inexplicably blinking into existence for no good reason is finally put to rest.

But this brings up another question. Is there a “first” universe, and if so, how did it come to exist? If there is no “first” universe, then are we comfortable with the notion that the lineage of universes goes back in time forever? Actually, why not? We can certainly imagine that the universes spawned by our Universe’s black holes will continue to spawn universes forever into the future. An eternal lineage of future universes is not too unsettling, so why not allow symmetry to be satisfied and accept an eternal past lineage of universes as well?

Well, it’s not that easy. That assumes that time is the universal stage on which the universes reproduce in successive fashion, which may not be the case at all. Time, strictly speaking, is simply a dimension of our Universe. Besides, it’s variable enough within our one Universe without the introduction of other universes. Some universes may have more than one dimension of time (just as ours has more than one dimension of space), and they may not even run at the same rate or in the same direction. Far be it from any self-respecting theoretical physicist to suggest that historical events can be chronologically ordered between completely different universes. To say that one universe “predates” another, even if it spawned it, may not even make any sense when speaking of the realm in which this web of singularity-linked universes exists. Even more unsettling, the web of universes may form a finite, but unbounded, manifold in which the succession of universes forms the equivalent of an endless loop. This would make our own Universe an ancestor to itself somewhere along the line. It could even be the case that our one and only Universe has actually existed more than once.

Whoops! So much for answering a few nagging questions. Still, merging the Standard Model with gravity is the Next Big Thing in the world of physics. Accomplishing this might actually be the first step toward answering more questions than we raise in our quest for knowledge. And while we, as a species, will probably never know for sure what goes on outside our own Universe, we may well prove, and perhaps quite soon, that no universe, including ours, could possibly exist if it weren’t for the mysterious black hole and what lies on the other side.

 

[Cees Alons]

Brian,
I we make a small () transformation: consider the radius of the universe constant, we're not exploding, but still collapsing (and shrinking ). The universe could be a black hole that's still forming (and we on the inside of it). How would we know the difference?
No explanations for a Big Bang needed. But some new ones ...
Cees
PS

Everything you see .... could be on the other side of a black hole that exists in a completely different universe

Strictly speaking that would not be a completely different universe. There's no hierarchy. The mass of a black hole was (and is) part of the same universe as the matter that stayed outside. It is only cut-off from each other for all practical purposes, in finite time. The universe would be much larger than we (can) observe. That's all.
C.

 

[BrianW]

Cees, it was your thoughts in the “other” thread that made me dig up and brush the dust off this idea and post it here. It would have lent to the continuity between our thought processes if I had posted the above in the other thread, but it really belonged here. Thanks for providing the link of continuity that was so lacking.

Strictly speaking that would not be a completely different universe. There's no hierarchy. The mass of a black hole was (and is) part of the same universe as the matter that stayed outside.

Perhaps I wasn’t clear, but I didn’t mean to suggest that the mass of the Universe has anything to do with the mass of the black hole that spawned it. I think we’re in complete agreement that throwing matter into a black hole merely contributes to its mass in the universe in which it exists, and not to the mass of the universe on the other side. So I completely agree that our universes are practically cut off from one another. And although, as you point out, there are compelling ways to look at our Universe as if it were inside the event horizon of a black hole, we are technically not inside the black hole that spawned our Universe. (This is not to say that we are not inside a black hole at all - we may well be!) Indeed, the spawning universe may suffer a Big Crunch, blink out of existence, taking all its black holes with it, and our Universe will be completely unaffected despite the fact that we are linked to it through a singularity. Saying that we are on the “other side” is quite an accurate way to put it. Perhaps it’s just semantics, but that’s enough for me to consider them completely separate universes. Besides, it sounds more mind boggling that way!
Oh, and it only looks like we are expanding toward the event horizon of the black hole that contains our Universe because (according to some) time runs backwards inside the event horizon. The Big Bang is actually the cataclysmic end of our Universe, not the beginning.

 

[John Spencer]

Black Holes - What's on the other side?

Uranus.

 

[Cees Alons]

Brian,
Yes I supposed you were reacting to my other post, and yes, I figured I could help linking it up neatly.
And yes, I think we agree on the multiple-or-not-so-multiple-universes concept .
Just for the intellectual fun, here are some loose thoughts:
(1) The notion, by some, that black holes suck-in matter is incorrect. A black hole attracts matter no more than with the gravitational force that's usual for it's amount of mass (which happens to be huge locally - granted). So if one succeeds in forming a black hole on earth, using available matter, there's no chance that the whole world will suddenly be sucked in in seconds - or even hours or years.
(2) If two existing black holes approach each other, whether they are on a collision course or not exactly, an area in between will start to form where opposite gravitational forces will start cancelling each other out. Will the "depression" in each of the event horizons now allow some matter to leave the black holes?
(3) Alternation of the direction of time is of no consequence to us. If you plant your foot in the sand (somewhere in time), there's one direction where an imprint will be visible, another direction where it won't. The way our chemical minds work dictate that we consider the first as "later", the second as "before". That's because the macrophysical effects that cause the imprint to "stay", is also responsible for our memory function and hence the way we experience the flow of time.
Cees

 

[John Beavers]

Thought I'd pass along another Black Hole theory that's come to light. Can you say Gravastars.
http://www.cnn.com/2002/TECH/space/0...ars/index.html