So one way Kashi, Jay and I were generally talking in the lab, and out of nowhere (as it usually does) the question (rather questions) of the Universe came up.
My personal favorite is this, and I’ve wondered about it since I was a kid: everyone seems to be convinced that the universe is expanding; but if it is, then where? To that, Kashi proposed (from what he had read/heard somewhere) that its perhaps expanding in a dimension that we can not perceive/comprehend. He gave the analogy of an ant walking on the surface of the earth—the great explorer ant might crawl all it wants, but it will keep going round and round on the earth, may be think its infinite or not understand it at all, primarily because it (supposedly) perceives the Earth as a two dimensional surface. Not a bad analogy, but I’m still not convinced.
Jay also asked an interesting question with an interesting answer. I’ve stupidly forgotten the question, but have pinged Jay about it and will update when I hear back from him Meanwhile the answer was ‘because the Universe is not all at the same temperature; and entropy and thermodynamics dictate that eventually all of the Universe must rest at the same temperature’—ok without the question that probably doesn’t make much sense, but it seemed pretty witty and funny at the time!
Ok, Jay confirmed that the question was “How do we know that the Universe has not existed forever?”