> the Planck length is presumed to be the smallest measurable distance before stuff turns into a black hole This is not correct. The Planck length happens to b

> the Planck length is presumed to be the smallest measurable distance before stuff turns into a black hole This is not correct. The Planck length happens to be very very roughly the scale at which we expect effective theories that ignore quantum-gravitational effects (i.e. the Standard Model) to break down. It has no special physical significance.