One can estimate the mass of the visible universe based on the number of stars, galaxies, etc. My estimate is 56.8E+52 kilograms. That around 4.389E+22 solar masses. Regardless of how much "light" is en-route between the stars, this amount of visible matter will generate a gravitationally-bound event horizon at around 89.1 billion lightyears distance, assuming we are at the center. This is the black hole-equivalent radius, that is, the point beyond which nothing can escape, not even light.

If someone has reason to disagree with this, I'd like to hear about it, because the equation is *really* simple. So simple it astonishes. So simple I'm shocked Newton didn't think of it 320 years ago. Certainly it should be common knowledge in the 21st century.... unless there are reasons not to support this interpretation?