So we see that space (the actual spacetime fabric itself) is enormously stiff (or enormously fluid, but that discussion will come later), but that's not all that's strange about it. It is also expanding. This seems a rather odd coupling of characteristics. Anything that is rigid resists bending or flexing in any way, yet the Universe is clearly expanding at an enormous rate. This forces us to wonder about the nature of that expansion. When we look to the heavens and see that all of the visible galaxies appear to be moving away from us (regardless of where in the sky we look), it begs the question of how they are moving. This may seem to be yet another odd question. If something is moving away from us, does it really matter how it is moving? In fact, it does. The question boils down to this: Are galaxies moving through space like cars on an interstate, or are they being carried away like suitcases on an enormous, invisible conveyor belt? This difference is a...