My cosmology friend and I were watching an episode of NOVA called "The Fabric of the Cosmos" hosted by Brian Greene. I asked if he could further explain the reference to the "fabric of the cosmos". He said, "Space-time has a geometry much like a piece of fabric. Picture our universe being constantly woven, sewn, mended, and extended on a great cosmic loom. The loom is driven by a treadle, which in turn is driven by a treadle beneath it." I asked, "What drives that lower treadle?" He said the funniest thing. How do you think he replied? Spoiler He said, "Isn't it obvious? It's treadles all the way down."