Kaluza-Klein and 4D

[darthbadass]

So KK theory as well as string theory postulates that higher dimensions are curled up at microscopic levels. Does this mean you can only experience 4D if you shrunk yourself down (physically impossible, by the way- what would you breathe?) to the subatomic, and is this why particles exibit all sorts of strange behaviors like spin 1/2?

[jinydu]

That is what I have read in many popular science articles. But I haven't looked at the detailed mathematics of it, so I can't say that I really understand it.

[houserichichi]

If you were to shrink down (defying all laws of physics in the process) to Planck-scale size you would be able to experience the compactified dimensions (assuming they're there at all). Remind yourself, however, that if you were to shrink down that small you wouldn't be able to keep your human form because you'd be smaller than atoms...so what you breathe wouldn't matter anymore

[darthbadass]

If you were to shrink down (defying all laws of physics in the process) to Planck-scale size you would be able to experience the compactified dimensions (assuming they're there at all). Remind yourself, however, that if you were to shrink down that small you wouldn't be able to keep your human form because you'd be smaller than atoms...so what you breathe wouldn't matter anymore

I know that, I was asking a rhetorical question in saying "what would you breathe". You would breathe vacuum, so you'd suffocate and explode because of the pressure of atmosphere not being there.