What does it even expand into like in terms of displacing the presumably “Nothing” that previously existed or didnt exist when the universe expanded and should have displaced or subsumed it?
What does it even expand into like in terms of displacing the presumably “Nothing” that previously existed or didnt exist when the universe expanded and should have displaced or subsumed it?
Space is everywhere, and it’s stretching. It isn’t expanding per say, it’s that everything that is everywhere is getting further apart.
You’re thinking of space stretching like an inflated balloon, and that’s a decent analogy but it’s far more simplistic than reality. If there is some cosmic boundary it would divide everything that is and exists, and the absence of any existence. It’s a boundary which light itself could not escape, and all future points of time exist only within that boundary. All of space time would fold back in on itself.
Imagine standing at that boundary and firing an arrow, a thought experiment first described by Lucretius in Pompeii 2000 years ago. He imagined that if he fired an arrow from the edge, then clearly the universe kept going, and if it hit something, then clearly something must exist on the other side.
But the arrow can only fall back in towards the universe at some such theoretical boundary. Because all points in time exist within that boundary.
Which is very similar to a black hole. Which is why some cosmologists have suggested that maybe we live inside one.
This would mean black holes can contain black holes, since we have also observed them inside our own universe/black hole. Which means there can be infinite universes inside each other.
😳 This toilet session turned into something else for me.
Here’s another fun fact then, any “cosmic boundary” would be surrounded on all sides by the universe, and would simultaneously exist at it’s center. Because every point in the entire observable universe is the center of the universe.
Which again sounds an awful lot like a black hole.
So maybe there is a boundary. It’s all black holes all the way down. interconnected universes all pointing to each other through black holes and Einstein-Rosen bridges all feeding off of and in to one another. The dark energy accelerating space time’s expansion coming from beyond our local event horizon in a brief moment of feeding.
I didn’t quite follow the reasoning of the first paragraph there. I would love some elaboration on that. 🙏
You are the center of the universe. A star, 2 billion light years away is also at the center of the universe.
Everything that is everywhere originated from the same infinitesimally small point that stretched out in to the universe we observe today. It’s not like a grenade going off, where you can point to a center and an edge. It’s more like proofing dough.
IF that is true, that means any “edge” to the universe must also exist at it’s center, and therefore be surrounded on all sides by the universe. It would look more like a 3 dimensional hole than a bubble we’re inside of.
Hmm. Does it make sense to say that two different points are the center? We can’t all be the center if we’re in different positions. In this case it makes more sense to me to say that there is no center. No?
If our universe exists inside a black hole, does that mean it would be potentially subject to collapse if “parent” black hole loses matter converted to energy and lost to the “parent universe” via Hawking radiation? Would this be our “big crunch”?
How do you know that isn’t already happening?
I don’t. I’m asking by applying what we know of physics in our universe, and assuming the same physics work in others (a big assumption I know). As in, I’m asking if my application is correct.