If Space is a vacuum with nothing in it, then what would the edge of the universe even mean

Question

…it would be a ‘border’ between nothing and nothing?

In: Planetary Science

Answer 1

So my understanding is as follows

1 Space is effectively a vacuum but there is small amounts of matter and energy flying around

2 The universe is everything so there is no “edge” in the same way that say a dinner plate has an edge

3 If you wanted to call something an edge you would say that matter or energy that has no other matter/energy father than it in a direct line away from the center of the universe is where the ‘edge’ is. But that edge is constantly expanding outward.