So I was thinking the other day, something negative is the opposite relfection of whatever your looking at, so I wondered, what would a negative dimension be? I had some thoughts like for the 4th it would reverse time and atoms would age in reverse for the period in the -4th dimension. I came up with other interesting theories about the other 3 readily describable dimensions, but i wont post them now. What do you think?

Well strangely,
A few years ago there was great hype about super symmetry breaking (the splitting of forces/dimensions etc) and a possible creation was an <b>E8 * E8`</b> type universe.

The E8 broke down further to form our space-time, while the E8` may have broken down to some thing different. The E8` would contain `negative` dimensions.
(<i>In the same sense as matter and antimatter</i>).
http://www.valdostamuseum.org/hamsmith/E678.html

But having said that it seems rather meaningless to apply a negative dimension into our space-time. (The negative of <b>up/down</b> is, er, <b>down/up</b>)

Maybe you can find this useful. The negative dimension approach
http://arxiv.org/abs/hep-ph/9907494

Assuming it has a side length of 5, a -2D object would be something with an 'area' of 1/25 and a diagonal of 5i(2)^1/2. A -3D object would be something with a 'volume' of 1/125 and a diagonal of 5i(3)^1/2. I can't fathom something that looks like this... and its obviously imaginary..... so we really can't understand it

Just because you can manipulate something with numbers does not mean that they represent reality. What is a negative dimension? What is negative length? A negative meter is one meter in the other direction is still a meter, is still distance. There is no meaning to a negative dimension.

Maddad,

Just because you can manipulate something with numbers does not mean that they represent reality. What is a negative dimension? What is negative length? A negative meter is one meter in the other direction is still a meter, is still distance. There is no meaning to a negative dimension.

Just splash some cold water in their faces, why don't you? :p

Just because you can manipulate something with numbers does not mean that they represent reality. What is a negative dimension? What is negative length? A negative meter is one meter in the other direction is still a meter, is still distance. There is no meaning to a negative dimension.

A negative dimension does not mean that the side lengths are negative tho.... you're right that a negative meter is one meter in the other dimensions.... but the definition of a negative exponent is to take 1 divided by that number.... so the lengths of the sides are really small, and the diagonal (the distance from one point to the farthest point in a shape with all equal sides) will be imaginary. You're right that negative dimensions are not real, but it is not true that there is no meaning to them.