Question about M-Theory dimensions

[MojaveJoe]

Hi all,

My apologies if these are stupid questions, just trying to understand it. In M-Theory there are a proposed new 7 dimensions. It was stated that these very small dimensions are on each point in our regular 3 dimensions.

What does that mean? Are they "anchored" to a point? What is the point then?

Thanks for your forbearance!

MojaveJoe

 

[selfAdjoint]

Hi all,

My apologies if these are stupid questions, just trying to understand it. In M-Theory there are a proposed new 7 dimensions. It was stated that these very small dimensions are on each point in our regular 3 dimensions.

What does that mean? Are they "anchored" to a point? What is the point then?

Thanks for your forbearance!

MojaveJoe

The seven new dimensions are orthogonal - "at right angles" to our visible three (or four, counting time). So each one of them is "at" each point of spacetime, just as "height" is available at each point of a flat surface'. Read Flatland if this breaks your mind.

Now the way that theorists explain why we don't see them is by saying they are curled up tight into really tiny little wads, way smaller than a proton. So none of our instruments have enough energy to probe that small a volume and they are invisible to our current and foreseeable energy levels.

This idea of curling up dimensions or "compaction" as the physicists call it is really independent of the idea of dimensions itself. The number of dimensions really does fall right out of the theory. Physicists have no choice in this. If they are going to do string physics at all, and M-theory is an advanced form of string physics, then they have to accept there are the six or seven extra dimensions. But compaction is an additional hypothesis. Pjysicists don't have to accept it, and some do not, although most do, and draw strong conclusions from it.

 

[MojaveJoe]

That does kind of break my mind, but I understand it conceptually. Think I'll take a look at Flatland.

Thanks!

MojaveJoe