What lies beyond the universe?

[♔Goodguy1066♔]

I have heard many times people saying that the universe is expanding. But expanding to what? I mean, look at this diagram:

Spoiler Alert, click show to read: 

It appears like a balloon that is being blown and is getting bigger. But unlike a balloon, which has a world and a universe outside of it, the universe is supposed to be existence itself. So what is outside the universe (the white place in the diagram)? Thoughts?

[MathiasOfAthens]

Nobody has any sorta ing clue as far as I know.

But a wild guess maybe an empty space before you reach another Universe (Balloon).

[G-Megas-Doux]

The assumption with the word is that this is the whole of existance and thus the Universe. The word space implies emptyness the vacancy of being. So the expansion is into the emptyness. The emptyness is never full as the most extream point of our Universe is still in the universe so never technically escapes. Any other Universal system a long way beyond our Universe would be classed as the whole of a Universe and a new term used to describe both individual things would be invented.

[DisgruntledGoat]

Well, current theories are that the universe doesn't expand into anything (not even nothing). It in fact create creates the nothing it expands into as it expands.

[Trax]

Well, the Universe isn't really like an expanding balloon, the universe has no center to start with.

[♔Goodguy1066♔]

Well, the Universe isn't really like an expanding balloon, the universe has no center to start with.

Well, if the universe started expanding from the big bang, and from there outwards, then surely the universe has a centre...

[Alkarin]

Well, the Universe isn't really like an expanding balloon, the universe has no center to start with.

um..big bang mate.

[Gordon Freynman]

um..big bang mate.

The BBT does not give the universe a center.

[Alkarin]

The BBT does not give the universe a center.

it gives a point of expansion therefore a 'center'

[Gordon Freynman]

it gives a point of expansion therefore a 'center'

There is no point of expansion. Space did not, and is not expanding from a single point. It expands from everywhere, like the surface of an inflating balloon.

[Syron]

To answer the actual question, according to present theory (which tbh isn’t well understood) the “(observable) universe” is expanding into the rest of the universe…….

Current Big Bang theory requires a process called Inflation, where in the first billionths of a second after the Big Bang the universe expanded at a phenomenal rate, expanding faster than the speed of light (before you start to crow, objects are limited to moving at the speed of light within Spacetime, Spacetime itself can move at any speed it wishes provided the energy is there to do it.).

This means that, because some parts of the universe have moved away from us faster than the speed of light, the light from them can never reach us and so are unobservable. This indicates that the extent of the known universe is not all there is, that the speed of light creates a “horizon” barrier where pocket universes form.

Of course, as I said, Cosmology as a proper science is relatively young and there are many unanswered questions of which hopefully some will be answered soon with new experiments.

it gives a point of expansion therefore a 'center'

The Big Bang was not a point in Spacetime, it WAS Spacetime (or at least the extent of it circa 13.7 billion years ago).

The expansion of Spacetime must be isotropic, all parts expand at the the same rate, if they didn't the universe wouldnt be as homogeneous as we perceive it today. I know that might seem strange but on the large scales the universe is essentially the same in all directions, hence the uniformity of things like the Cosmic Microwave Background.

Imagine the deflated balloon crunched up in a ball (the Big Bang), there is no centre to it’s surface. Now inflate the balloon, there is still no centre to the surface of the balloon.

Time and space are Einstein's 4th spatial dimension called spacetime. He asserts the two are intrinsically linked. It was this assertion that lead to his monumental theories.

Certain properties of Time act like a spatial dimension, (for example when you perform a rotation transform on them), which Einstein showed had important results like the one you point out, but that does not make it one. Yes they are intrinsically linked, but they are NOT the same.

[War&Politics]

Well, I'm no scientist but keep in mind that we humans use certain concepts to help us understand the world. For example the concept being used here is that if there is an inside there must be an outside. But who's to say that concept is the truth? After all, our eyes lie to us all the time. Look in the distance and the earth certainly doesn't appear to be round. Yet it is. So maybe there is nothing at all outside the universe.

[Elfdude]

The universe does not expand or contract from the outside what we are observing as inflation of the universe is actually just the effect of space in the 4th dimension called spacetime. So the universe is expanding on the inside because it is infinite in spacetime dimension but not on the outside because it is finite as far as the initial conditions of our universe go.

[Niles Crane]

That's right, ask the internet for the answer that nobody on earth knows or (likely) will ever know.

[Solid Snake]

The Spaguetti Monster is outside of it...pulling the strings....

[Swagger]

needle, then big bang2

[G-Megas-Doux]

Starbucks.

[Solid Snake]

I heard there is a cool restaurant at the end of the universe.

[G-Megas-Doux]

I heard there is a cool restaurant at the end of the universe.

There will be a well known coffee shop next door then.

[Trax]

Well, if the universe started expanding from the big bang, and from there outwards, then surely the universe has a centre...

It isn't that easy, every location in Universe is equal, that means every point is as good as centre - otherwise we end up with some sort of glorified form of geocentrism.

The balloon thing is just a nice analogy that helps to imagine the unimaginable.
Try to see the Universe as the surface of the balloon not as the interior space.
Where is the centre of the surface of the balloon?

And to everybody else - cut the spam!