Always wondered that. Now I can go back to figuring out the mass of the universe. Did you know the universe could be 10,000,000,000,000,000 times bigger then the 90 Bly diameter that we can see if the theory of inflation is correct, which most physicist's agree that it is! So far I have figured out the universe weighs more then 1 kg, but my math needs some work. The universe has 10^80 particles and a volume of 10^120 plank volumes. You would think it would be bigger but those are insanely bigger numbers that you can't possibly "see". The most of something I have seen is 1,000,000 which was a 4 sq ft piece of paper with 1,000,000 periods printed on it which just appeared as a blur when you looked at it from more then a few inches back. Then think that the US government wrote a check for trillions of dollars that would be 1,000,000 of those sheets of paper, that I can't fathom.