Quote Originally Posted by MadMojoMonkey View Post
Yah, if you're gonna highlight that quote, then as a physicist I can pretty much squash it.

The Planck length is just a number. It's achieved by taking some other constants and multiplying /dividing them via dimensional analysis to come up with a number whose units are length only.

It does not represent anything physical, and any notion of what it might represent is purely hypothetical. As was mentioned, there is no physical way to measure anything that small.

On the point that space is granular on some scale. I take it you mean that on some scale a thing can be at point A or point B, but nowhere in between.

IF this were true, then there would be diffraction planes in space (albeit immeasurably close together, and not necessarily stationary). These planes would alter the way waves travel through space and would have very measurable effects. For one, certain frequencies of light would not travel in certain directions.

Also, quantum mechanics shows that a particle is not a pinpoint-localized phenomenon, but a kind of fuzzy bordered area of probability density. There is no way for a particle to be in a "single place".

Recall the link between position and momentum. The more defined the momentum is, the less defined the position is. Since there are always reasonable limits to place on the momentum, there is implicit uncertainty in the position.

If that's what you meant by granular space, it's pretty well disproved.
No I was not really talking about a thing being at point A or point B because by the uncertainty principle, the position of "a thing" a this scale is definitely fuzzy. I was more talking about the very nature of space-time itself.

I think that the truth is we have no idea, since we have no complete theory of quantum gravity as of yet. While I have not studied string theory, I read that it seems to hint that the universe at such a short scale is neither continuous, nor discrete but something else entirely which we don't understand yet. Other theories point to a discrete structure, and others yet seem to disprove it.

http://physics.stackexchange.com/que...-or-continuous

Wish I had time to go back to university and study all that properly, or even study it by myself. I have an engineering degree but sadly we went nowhere near deep enough in theoretical physics. In particular quantum physics and the relativity theory are absolutely fascinating to me.

If there is one thing that annoys me, it is that I will probably die before humanity gets to the bottom of this and finalizes a theory of everything..