Roughly speaking, the observable mass in our universe is all attributed to stars and gas clouds in the galaxies.
(a) Assuming that each galaxy contains the mass of 200 -billion Suns and there are 200 billion such galaxies, what is the Schwarzschild radius of the universe?
(b) Modern observations indicate that there is much more mass in the universe than can be “seen,” in the form of “dark matter,” neutrinos, etc. Suppose that the actual mass of the universe was 100 times larger than the visible mass. What would the Schwarzschild radius be under those conditions?
(c) Current observations place the lifetime of the universe at about 13 billion years. Compare the distance light can travel in this time to your answer from part (b). Can you conclude any-thing about the universe itself being a black hole?