[Right_Wing_Madman]

Whatever is expanding has to have something to expand into. What is that something?

This question is not possible to answer for two reasons:

1. We can only observe the observable universe, not the total universe, and not what's outside the total universe.

2. We don't know the geometric shape of the universe. It's either closed (like a globe), open (saddle-shaped), or flat (like a piece of paper).



If the universe is closed, it is finite. This means a spaceship could theoretically fly in one direction and eventually arrive at its starting point from the other side it departed.

If the universe is open or flat, it is infinite, meaning the spaceship would fly forever in one direction.

So far, all observations and measurements suggest a flat universe, which means the universe is infinite and it is expanding into infinity.

[odawg]

“This means a spaceship could theoretically fly in one direction and eventually arrive at its starting point from the other side it departed.”

Or, as one scientist said, if you had a powerful enough telescope, you would see the back of your head.

[Larry Lucido]

[It's either closed (like a globe), open (saddle-shaped), or flat (like a piece of paper).]

I think it's like a glove.