The universe is flat (currently supported)
The universe is simply connected (the edges aren't glued together as in a torus)
The universe contains finite mass and energy
The universe must have an edge.
Yes, there is a similar question here: How can the universe be flat and have no center if universal mass-energy content is finite?
But my question is not answered. In fact, people are neatly dodging the notion of an "edge" by suggesting "unusual topologies"
This is a purely hypothetical question, but since everyone says the universe has no edge and is flat, I am forced to ask the obvious: space or some form of truly empty vacuum might go on forever, but if matter/energy are finite in the universe, then eventually, if we travel far enough past the cosmic horizon, we'll find that there are no more stars, no more galaxies, no more photons... and no more anything. Unless the universe is actually a sphere, in which case eventually we'll end up back where we started.
Is there a flaw in my reasoning? I must have read 100 articles today to get to the bottom of this.