This light verse limerick packs a profound punch. At 13.7+ billion years, our universe has had a long time to expand and grow to it’s present size of one hundred billion galaxies in the observable universe. However, we have learned that this cosmic view is limited to the speed of light within space, while space itself has no such restrictions and apparently expands at any speed at all, even speeds faster than light.
What this means is that light from its furthest reaches may one day no longer reach us, forever preventing us from observation of what essentially becomes a separate universe. Add to that, our mathematics tells us that our bifurcating universe might not be the only infinitely expanding cosmos. Our entire universe may be just a membrane floating in what’s dubbed the “bulk,” alongside an infinite number of universes — The Multi-Verse.
These parallel universes do not interact electromagnetically, and so we will never see them. However, we may be able one day to detect their gravitation. If we are ever able to hunt down these universes that could be located centimeters away as dimensions are reckoned, we may find that the laws of physics operate differently in each one. Some may not be able to form stars, and by our standards seem infertile. There are even theories that when membrane universes (“branes”) bump into one another, they experience Big Bangs within their empty branes, but that sounds like a sequel limerick.