The Planck Length
There are ongoing efforts to develop a workable theory of quantum gravity: string theory and loop quantum gravity, for example. In the absence of such a theory that can successfully deal with gravity and quantum mechanics simultaneously, the Planck scale is as small as it gets. The Planck length is 10-20 times smaller than the proton. By comparison, a bacterium is 20 orders of magnetude smaller than the sun. There is an enormous variability in that range. Perhaps there is just as much variety in the scales larger than the Planck scale.
Unfortunately, the Large Hadron Collider at CERN, the world's largest and most powerful particle accelerator, has only begun to probe with energies that provide hints at what is going on at 10-17 and 10-18 meters. So, for these pages, the next jump up is a huge one, to 10-18, the realm of the energy of a Higgs boson.
Copyright © 2016 by Bruce Bryson