# Plank's Constant/Length

1. Jul 10, 2013

### michojek

Hello, I was just reading upon plank's constant and it was theoretically the 'smallest measurement' possible.

Does that mean that space itself follows this rule?
For example, you can't have an atom 'between' a plank distance..(like a grid where you can only have positions in the intersections of those lines)

So the smallest distance an object can you is a plank a time?

I'm just not sure if I have the right notion of plank length..

Thanks!

2. Jul 10, 2013

### DiracPool

Its not a rule, its a theoretical figure, 10^-35 meters, derived from fundamental constants of nature, such as the speed of light, c, Newton's gravitational constant, G, and Plancks constant, h. Some theoretical physicists truly believe its the fundamentally smallest unit of length, others are not so sure.

Considering that an atom is many order of magnitude larger than the Planck length, as in perhaps 25, then, yes, you cannot have an atom between a Planck distance. However, that does not mean that there may be something, such as quantum "space-time foam," etc. that may do so.

?

I'm not sure what that sentence is supposed to mean, but there is indeed a Planck time, which has been derived similarly to the Planck length, and that figure is 10^-43 seconds.

3. Jul 11, 2013

### Bill_K

You mean the Planck Length. Planck's constant is something else entirely.

The Planck Length, √(ħG/c3) is a length scale, not a precise value. It's roughly the distance at which the effects of quantum gravity are expected to become important. There is no implication that it's the "smallest" distance, or that space becomes a discrete lattice at that scale.