Either you know or don't know, but there is no such thing as a perfect sphere in our universe. Or perfect circle either. Some scientists say that black holes event horizons could possibly be, others say that is not the case.

Either way, this is perhaps why Pi is irrational. In the way that a sphere is impossible, pi is impossible to be a fraction. Thus we come to a sort of philosophical question : what does this say about many things? That things themselves are impossible, thus their study is un-quantifiable. Just some thoughts.

Eh, we already reached that result with Heisenberg's uncertainty principle. We don't know enough about black hole event horizons to make any claims regarding whether or not it is a perfect circle or not.

Coolio