Hello globus_hystericus. Welcome to the SDC forums.globus_hystericus":26x533wt said:My first post, so be kind :lol: A few years ago I had the good fortune to take a graduate course in GR and review recent findings relevant to the discussion. To limit the discussion to theories verified so far, general relativity, and make a few reasonable assumptions: the universe looks the same in all directions and the composition is the same everywhere, then GR gives three choices to shape of the universe: open, closed and flat. To make a long story short recent measurements by COBI and other spacecraft have pretty much nailed down the shape of the universe as completely and amazingly right on the money FLAT. That means the universe is and always was infinite in size. Don't be confused by the big bang and universe the size of an atom point of view. The big bang was a singularity and thus can't be characterized but right after the very hot early universe was already infinite in size. Then it got even bigger! How can infinity get bigger? Simple, every point moves away from every other point in time. Also don't be confused by the size of the universe being 46 billion light years across, that's just the observable part, the part within our light cone stretched out by inflation. The rest of infinity is still there, remember assumption number one and two (isotropy and homogeny). As for the center, well, its everywhere, or nowhere; every point can consider itself the center of its observable universe but there is no true center as in what is the center of a geometric sphere.
I don't think cosmologists are ready to say the universe is or isn't finite. We may never know for sure. The Planck space telescope is imaging the sky to better understand it, but the work is just beginning.
Was I kind?