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

it’s been theorized that universal curvature may not be flat and that it gently slopes away from observers in all directions but we have not been able to build sensors big enough to test this. So far we know it is flat to within 0.4% margin indicating that it may be infinite in nature. In which case you could travel forever in a single direction at any speed and never find an edge or hard boundary.

However if this were not the case and the universe were a sphere it would be finite but still would not have a hard boundary. You could travel forever in a single direction but you would simply pass the place you started.