If our universe is expanding then what space is it occupying?

Question

If a body expands it occupies some volume.
So for the universe to expand from where did this volume come from?

Answer 1

if our universe is expanding, then the space it is occupying is unoccupied space! =)

actually expand is an incorrect term, expand means to increase, increase means add, and according to the law of conservation of energy nothing is created or destroyed but changes form. so, the universe is only equally distributing itself like gas in a contained volume, the gas will distribute itself to equally fill the volume and that is what planets are doing when they 'expand' into space which has no boundaries that we know of. it reminds me of trying to divide something into zero parts, division by zero, its just undefined.

Answer 2

The universe expands. Fact! The question is answered quite easily when you ask yourself what the universe actually is. Is it the stars and galaxies? Yes! Is it the nebulae and black holes? Yes! But is this all? NO! the biggest part of the universe is the space in between. This is what expands.
To find out what it is filling up while expanding you have to get outside the universe. But what is outside the universe? What comes to mind here is heaven, the netherworld, paradise, valhala,...
Imagine being a raisin in a cake. When baked the cake gets bigger --> The raisins move away from each other without moving through the cake (=universe). Being outside you see it fills up the space around it. But in the universe's case we cannot get outside. The universe is defined as space (3D) and has a timeline (propably a 4th Dimension) To actually see what is beyond the universe you would have to be outside our 3 or 4 Dimensions. This we can not achieve at the moment (and propably never will) but can't even truely imagin. Our brains are not made to cope with a 5-dimensional grid.
So, and now we mess it up alltogether: The universe is said to be infinite. What do you get, when something endless gets bigger?
This is the point where even scientists sometimes come up with special principle. THis principle is also used on the other end of the timeline, the big bang. All matter, time and space was once confined in a single point of (infinite) density. This then exploded what we now call the big bang. It is one thing to imagine there is all cramed together in one point. When you manage this trick then go one step further: Was was there a second (with there being no TIME yet we could also say just "before") prior to the big bang? And what was arount that point? Theory has it that there was nothing around, not even a vacuum. This is exactly that point where the principle comes in. This principle now, in everyday speech, we easily call God.
I know this is not a satisfying answer but what you are asking is not a thing we can grasp with our minds. We are bound to imagine things in a frame of reference, this being at best an empty space (3D + time at most).

To make it short: It is the volume that expands. What it expand into is not to be measured using our sophisticated tools. Time was a better one as we knew that earth was flat (as said by Mr. Jones in MiB)

Answer 3

the universe is not expanding into some volume, rather the distance between the objects in the universe that we see is increasing. as we can only see a certain distance, we must take guesses at what lies beyond our field of vision.

the distance we can see is not limited by our instruments, however. what it is limited by is the time that light has been able to travel through space, for at some time in the past the universe was opaque. this was changed during the 'photon decoupling'. this moment is captured in time and light reaching us from just after the decoupling appears as faint microwaves... our 'view of the big bang' - the cosmic microwave background radiation.

so we have a limited field of view, called the 'observable universe'. we must make educated guesses at the shape of the universe beyond, but the idea is that it has no boundary or edge, and it either extends indefinately or it wraps around on itself in some shape.

My guess would be that the volume does not 'come' from anywhere, so much as it just 'is'. The volume is an absolute, a quality of the universe.

Here, think of it this way: space is the distance between two objects. So there is nothing outside of the universe. Who cares if it's true? It sounds good.

Depending on how you want to look at it, the big bang either has no center, or else every point is the center. All matter, and for that matter, all space was located at one point. We know that things are on average all moving apart at a certain speed, so if we extrapolate into the past we know that they were all together at some point. Knowing what this looks like by exploring the idea with general relativity, we assume this 'big bang' scenario.

Logically, what is outside of this universe does not exist, because it has no effect on us. Because it has no effect, no scientific instrument could detect it, thus we have no reason to suppose its existence, no ability to prove its existence, and no reason to care either way. It is not even a place that needs a name. The universe is not a container, it is a universe. It doesn't have an 'outside'. We know it is not a container because containers clearly have outsides to them. Universes don't seem to have outsides at all.

Answer 4

in my view it must be filling a vacuum
this explains why the universe is expanding.

Answer 5

It is very hard task to image "nothing". It means emptiness: everything is really excluded from emptiness. If the expansion of our universe really occurs, this emptiness is filled with something: material or energy.