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Originally Posted by uniqueuponhim
Also, if it were true, just as a sort of side-just-for-fun-question, at what distance from the universe(and by universe here, I mean the collection of matter which comprises it, not the space it encompasses) would it become just a star-like point to the naked eye, and how far from the universe would you have to be for it to be too faint to see at all with the naked eye?
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I'm not entirely sure that you can separate the matter and the space (but that's not the question). Here's the answer, assuming that from the outside (sic), the universe is a sphere (and that light travels outside, and that it's an Euclidian topology, yada yada yada).
Let's measure the size of the object as an angle, so you can decide how close to a point you want it to be. We'll call that angle theta.
First, there's a nice simplifying assumption we can make. Since we're talking about looking at a sphere that is almost a point, we know that the observer is going to be sufficiently far away from the object that we can consider the thing to be a 2-d circle, facing us. (The lines are almost parallel, and almost reach the "equator" if we are looking from one of the "poles.")
So, we get a nice isoceles triangle with base 2r and top angle theta. We want to solve for the height.
tan(theta/2) = r/h --> h = r/tan(theta/2)
Taking 2*r ~= 70 GLy, as cran suggested, and assuming 1' arc (1/60 degree) is pretty close to a point (
http://www.tedmontgomery.com/the_eye/acuity.html ), we get
h ~= 35 GLy/tan(1/120 degrees)
~= 24 000 GLy
24 000 GLy * 9.47*10^15 m/Ly = 2.3 * 10^29 m
That is a pretty big number.
(Does anyone else hate degrees, and just wish we did everything in radians? I do!)