What exists outside the universe?

[Datenshi-san]

I've been thinking this over for a few weeks now. If the universe is always expanding, what is it expanding into? And if the fabric of spacetime can be ripped, what happens when matter and light escape it into that void? It there another universe? Nothingness? Or is there something else we possible could never understand?

Its hard to say since obviously no science would be able to talk about that, after all physics is about interactions of particles INSIDE the universe's laws, it says nothing about outside spacetime. I believe there has to be something, after all we are expanding into it and obviously gaining more of this "dark energy" as we do, causing us to expand even more. This means that dark energy exists out there, and if that does, what else possible could? More universes? Whatever created the universe? Lots of questions and so far only hypotheses to guess at them.

[logan the god of candy]

outside of the universe there is most plausibly either a multiverse or nothing

[Raa Raa Rasputin]

Nothing can exist outside of the universe because there is nothing outside of it. I mean there is no physical plane for anything to exist. Because of this the universe can expand.

[The20]

Raa Raa Rasputin

Nothing can exist outside of the universe because there is nothing outside of it. I mean there is no physical plane for anything to exist. Because of this the universe can expand.

If nothing can exist outside of the universe why does the universe exist? After all the universe technical exists "inside" this nothingness.

[Layra-chan]

The universe doesn't necessarily have to be expanding into anything. It can simply be expanding on the inside, whereby expanding means that the concept of distance is changing, not that the universe as a whole is actually moving outward.
Consider a road. On day 1, we declare this road to be 1 kilometer long and define a kilometer thusly, and define everything that mentions distance in terms of this notion of a kilometer.
On day 2, we declare the road to be 2 kilometers long, and redefine everything accordingly. The road hasn't actually gotten any bigger, but from the point of view of those having to deal with distances, everything is now farther apart.
This analogy is terribly flawed in that it doesn't extend past the idea of redefining distances, but the important part is there: just because the inside of the universe considers itself to be expanding doesn't mean that the universe as a whole is actually getting bigger.

Nor does the universe have to exist inside anything at all. You're thinking of the universe as a finite object embedded in a larger space, but this might not be the correct way to think of it at all. It is mathematically possible to consider objects without reference to any embedding, so it could be that physically the concept of physical existence is restricted to the universe; the universe is everything that exists.

As for the idea of the fabric of spacetime being "ripped", there is no possible mechanism for that to occur in any physical theory. By rip, I'm taking that to mean that there is a possible path that an object can take that isn't fully contained within spacetime. If there is a "rip" in spacetime that leads somewhere, we can simply incorporate that somewhere into our notion of universe and extend spacetime so that the rip disappears. If the rip doesn't lead anywhere then we get a violation of various conservation laws. So we don't consider rips to exist.
Just to be clear, the notion of a "fabric of spacetime" is a purely Classical Physics/General Relativistic notion. The ideas of time and space in quantum mechanics become very fuzzy, possibly becoming discrete at very small scales. In proposed models for quantum gravity, the situation can become even worse. But in all of these cases we still have no "rips" in that objects in spacetime remain in spacetime (assuming there is a notion of spacetime).

[rescue_me364]

uggh
I get brain farts when ever i think about this.

[logan the god of candy]

if you can walk forward, then that is because there is functionally nothing in your way.

if the universe can expand then that may be because there is nothing in it's way.


for the universe to not be able to expand, there would have to be something outside of it to keep it from expanding, yes?

again, there is most plausibly nothing outside of the universe.

[Enchantingly Unexplained]

Take a while to contemplate on the concept of nothingness.. A question like this isn't something someone else can answer for you. You have to find the truth for yourself.

[McDrummin]

we don't know...

bottom line, we don't know anything about anything we can't observe, so we can't know anything.

lol. what if there are millions of other "-verses" like ours just really far apart in space, each with it's own big bang and such. what would happen if two of them ran into each other?

not a real question, just a funny though or one to make you feel really small

[xXxXxXxXxXxXxsh1tz]

I was actually thinking about this earlier. Awesome. xD

I believe the universe has the potential to be infinite..
So what lies beyond this universe are probably infinitely more universes that expand it further beyond things we could never even dream of without needing to either die or drastically improve our technology and knowledge of reality waaaaaaaay beyond where it is now.

We might get to see the tip of the iceburg someday, but...
I believe "reality" is much more expansive than we can ever truly become aware of as human beings with such short life spans..

Or maybe if there is a library with outer-universal knowledge, like the Akashic Records, we could find out.. x3

[baka_evalu_chan]

My brain hurts D:

Maybe the universe expands because there is nothing containing the force of it expanding. It's like when you suck the air out of a can. The can implodes because of the vacuum. Think of this example but instead of a can, the universe expanding into nothingness because of no force being there to make a balance.

[whateverfloats]

What is the universe expanding into? Nothing. There is no space outside of the universe for the universe to expand into. Space itself is expanding. Yup, it makes no intuitive sense but that's the theory. If there is anything outside of the universe we cannot know it and so it is useless to speculate.

[anomino]

I don't know, scientists say that the universe started with a event called a big bang. I also think they said that it started with an explosion and there were these kind of particles and gases floating around and eventually they formed into stuff. I forgot, lemme research that again.

[Bismuthe]

Blast our ability to imagine! gonk

[The20]

baka_evalu_chan

My brain hurts D:

Maybe the universe expands because there is nothing containing the force of it expanding. It's like when you suck the air out of a can. The can implodes because of the vacuum. Think of this example but instead of a can, the universe expanding into nothingness because of no force being there to make a balance.

Then why was the universe a singularity in the beginning?