This thought came to me while I was reading.

If the universe is expanding, then it needs to expand outwards into something. But this means that there needs to be something outside of the universe for it to expand into. The term universe tends to refer towards everything. But if there is something outside of everything then that means that the universe is not everything. Does this therefore mean that the universe is finite? 

Find out what "expanding universe" means in physics, not in your imagination.

1 hour ago, Genady said:

Find out what "expanding universe" means in physics, not in your imagination.

That appears to be what they are trying to do by posting here.

1 hour ago, Saturn11 said:

If the universe is expanding, then it needs to expand outwards into something. But this means that there needs to be something outside of the universe for it to expand into.

That is not correct.

Quote

The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time.^[1] It is an intrinsic expansion, so it does not mean that the universe expands "into" anything or that space exists "outside" it. 

https://en.wikipedia.org/wiki/Expansion_of_the_universe

53 minutes ago, zapatos said:

That appears to be what they are trying to do by posting here.

They did not know what is wrong in their logic, and I pointed that out.

4 hours ago, Saturn11 said:

If the universe is expanding, then it needs to expand outwards into something.

You're denying the possibility of intrinsic growth. 'Intrinsic' as in 'intrinsic geometry'. Things you can find out about without necessarily embedding them into a bigger, wider, more comprehensive ambient reality.

'Intrinsic' characterisation of geometric properties was a fundamental concern for Bernhard Riemann.

Isn't it possible to define intrinsic growth?

This is a question that I pose to you.

Infinity is not a number, and has certain specific rules that must be followed.
For instance, if you add to infinity, or subtract from infinity, you still have infinity.
Doesn't matter if you add 1 or 1Trillion; if it changed after the addition, then you didn't have infinity to begin with.

IOW, you can 'add' as much extent as you want to an infinitely extended universe, an it will still be infinite.