Provable Dimensions

**Chaigidel** · July 03, 2007, 07:34 PM

How many and what are the nature of the mathematically provable "Dimensions"

I have heard of 13 quantum ones 4 that we exist in--- so can anyone explain the mathematically provable dimensions in physics?

**Bootsiuv** · July 03, 2007, 09:48 PM

I've heard of 11, although I have a hard time contemplating this. The first 4 is easy, it's the other 7-9 that I just don't understand. I would like to see this answered as well.

**chris_uk_83** · July 04, 2007, 03:29 AM

"Dimension" in physics means something completely different than you're probably used to. Put simply, it's any quantity you can measure that has direction (though there's a little more to it than this; the mathematicians can probably define it better).

As an example, you know we have 3 spatial dimension, that's easy. Time is a fourth dimension, again that's relatively straightforward to imagine. You can also have momentum dimensions. This is just the name given to momentum in different directions. You have three of these, making 7 overall. Extra dimensions are really just a naming convention for quite straighforward things like momentum (which has it's own 'momentum space' in order to carry out more complicated maths).

I believe that other spatial dimensions may be predicted by things like string theory, but that's best left to string theorists, who aren't entirely in touch with reality

**Shatterer** · July 05, 2007, 02:02 PM

Originally Posted by chris_uk_83

Extra dimensions are really just a naming convention for quite straighforward things like momentum (which has it's own 'momentum space' in order to carry out more complicated maths).

So then does force have it's own set of dimensions as well?

**Kennylz** · July 04, 2007, 03:32 AM

String Theorists make me want to run up, and do something totally random to them, just so they can stay awake at night trying to figure out what I did in one of the other dimensions.

**Chaigidel** · July 04, 2007, 11:02 PM

so the quantum dimensions are not mathematically provable ? ( im pretty sure they arent the same as dimensions of momentum right?)

**chris_uk_83** · July 05, 2007, 04:02 AM

Well they probably are, but I don't know how to do it. I'm an experimentalist rather than a theorist.

I do know that String theory begins with "assume there are n dimensions". The point is that dimensions are arbitary really, and could well simply be a mathematical construct to explain something.

I don't know what you mean by "quantum dimensions" though.

**Chaigidel** · July 05, 2007, 08:24 AM

I thought there were 12 or 13 "tiny" dimensions around everything-- thats what I understood to be "quantum" dimensions

**chris_uk_83** · July 05, 2007, 09:21 AM

"Quantum" just means "quantised", which means there's a minimum size / duration / energy associated with everything and that everything must work in increments of those amounts. The entirity of quantum theory is based on that principle.

Quantum has been taken to mean "small" as well, which isn't strictly correct. Yes, things considered with quantum mechanics are small, but quantum doesn't mean "small", the two are just usually associated.

**chris_uk_83** · July 06, 2007, 03:33 AM

Pretty much yes. Since a dimension is simply a mathematical construct. You're probably better asking Sim about the particulars of this topic; he's better at maths than me