The expansion of space divides it into a number of causally disconnected regions. For all intents and purposes, these regions are not part of a single universe; rather, each is a universe of its own. Each point in space is surrounded by an impenetrable cosmic horizon, the size of which is determined by how fast space is expanding. The faster that space is expanding, the closer this cosmic horizon will be to the point that it surrounds. During eras of accelerating expansion—such as our current era—space is continuously being divided into a larger number of disconnected universes. And while this
...more
