I remember trying to compute the Swartzschild radius of the universe during my GR class and thinking it was compatible with the whole universe being inside a black hole.
According to wikipedia [1] it turns out it's a bit smaller than that, but the same order of magnitude.
Wow! That's a revelation to me! So, in effect, that implies that information cannot escape the "boundary" of the universe as nothing can surpass the speed of light, ie, the universe is a black hole. This would certainly explain some things - like why energy is conserved, why (some) physical constants have the values that they have.
According to wikipedia [1] it turns out it's a bit smaller than that, but the same order of magnitude.
[1] https://en.wikipedia.org/wiki/Schwartzchild_radius