>>13207037it means that on average spaceyime on the large scale isn’t curved. so for example if you shoot two beams of light out parallel to each other, they will stay parallel in the normal sense, i.e. they won’t bend toward or away from one another unless they go close to some big star or black hole or something.
actually the universe is slightly curved hyperbolically, and actually parallel light rays will diverge if they keep traveling far enough (if they don’t pass by any big things), and this has to do with the expansion of the universe
