# planck the crank

so okay, planck heat/energy i have some kind of handle on. my problems are with his length and time. as i understand it, a distance smaller than the planck length no longer IS distance, in some esoteric physics way. same with the time. isn’t that like saying 2 seconds is time, but 1 second isn’t? what do they become when they get too small?

~dan

They don’t become anything. That’s the point. Distances smaller than the planck distance or times shorter than the planck time may exist but cannot be meaningfully described or manipulated by the Standard Model in physics.

That’s all that physics does, really. It describes reality. If it can’t, then it breaks down. Our current understanding breaks down at the planck level, and physicists are searching like mad to extend, upgrade, or replace the Standard Model with something that will handle these tininesses.

okay, thank you. this makes much more sense than what appears to be the standard explanation, which is that they are lower limits, not of our understanding, but of the concepts length and time themselves.

not that having them be infinitely divisible makes any more sense, when you really get down to it. it’s a little easier to think about, though.

Well… really in the models out there they are lower limits on length as we think of length. One weird effect is that all distances measured (in some models) are multiples of the Planck length. Measure one side of a tiny square and get the Planck length. Measure the next side and also get the Planck length. Now, measure the diagonal and our normal understanding of geometry makes us expect to get sqrt(2) times the Planck length, but in these models you can only get integral multiples. When we start considering systems whose sizes are on that order, all our intuition about geometry goes out the window.