[photon]

Originally Posted by GoinAllTheWay

I understand exactly what you are getting at with the expaning balloon example but would it not be more accurate to say we are living within that balloon and that the space inside the balloon is also expanding?

No! That's exactly wrong

The problem with our brains is we are not equipped to think beyond our experiences, so trying to think of taking something 3 dimensional like space, and say now think of that curved, just doesn't work.

So what is often done to try and help communicate things is to reduce things down one level.

So take our entire 3 dimensional universe and squish it to 2 dimensions, only width and only length, no height.

So the surface of the balloon represents the universe. You can only move freely in two dimensions, the third dimension (up and away from the balloon or down and towards the inside of the balloon) makes no sense.

Now glue coins onto the balloon, these are galaxies. Now as it blows up, the coins are all getting further from each other; space between the coins is getting bigger.

EDIT: If it helps, ignore the balloon and think of a flat rubber sheet of infinite size that can be stretched in all directions, the analogy holds.

The universe isn't expanding "into" anything, it's just getting bigger. If you could create a faster than light ship, you couldn't travel really fast and find an edge, because there isn't one*.

Now take that analogy and try to imagine it being translated into more dimensions. The "surface" is 3 dimensional space.

*I say there isn't one, but origins of the universe (and thus the properties of the universe beyond what we can see and back "before" the big bang) is something that is mostly speculation, some ideas have the universe being regions of inflation in a much bigger universe in which case there would be an "edge" to our universe, but that edge would just be more universe.

To say we are living on the surface of it would suggest that the real world equivalent would be like living on the extreme edge of the expanding matter?

Not quite sure what you mean here, the surface of the balloon is everything that exists, the inside and outside of the balloon in the analogy don't even exist.