Is our universe constantly expanding or constantly shrinking?
Allocator2008: Oh, I just had another thought here. I would so very much prefer it if the Hoyle steady state theory were correct, the idea that as galaxies expand, new matter is created in the inter-galactic spaces formed by the expansions, and this new matter makes new galaxies, ad infinitum, so there would not be a big bang (a beginning) or a final state of dissolution into radiation that one finds in the eternal expansion model (an end).Also it is a clean, beautiful theory mathematically. But as Kepler found, when discovering that the planets use ellipses and not circles when orbiting the sun (circles were thought more "perfect" aesthetically at the time), the universe might not much care what we like or prefer or find to be beautiful or aesthetically pleasing. :-) In the case of steady state, it is hard to see how that can still be viable, given the microwave background radiation discovered in the early 60's, and the more recent discoveries of quantum density perturbations in the background, which is consistent with the big bang model.