Imagining a Cosmic Edge: What a Nearby Observer Would See
The piece explains that while the observable universe is isotropic and flat with no evidence of an edge, current data allow for a much larger or even infinite cosmos produced by cosmic inflation; if an edge exists near us, an observer there would see an abrupt boundary with nothing beyond, and the only detectable signal would be Unruh radiation from the inflating space—though such an edge would lie beyond our horizon, making it effectively undetectable with present measurements.