# Are we living in a Universe with 3 time dimensions and 1 spatial dimension? [duplicate]

If I said that we are living in a Universe with 3 time dimensions and 1 spatial dimension, would I be wrong?

By that I mean if the spacetime interval was evaluated as -time1^2-time2^2-time3^2+space1^2 instead of space1^2+space2^2+space3^2-time1^2.

Is there an absolute difference between a spatial and a time dimension, or are they like the positive and negative electrical charges?

Edit: This came to me after reading a question considering more than 1 time dimensions. I think it was about a 2+2 universe, which prompted the question "Which 2 would be the time dimensions?"

So I guess the real questions is, is time's property the fact that it is a single dimension of its type/sign, instead of 3? Could we talk about spacetimes only for 1+N pseudo-euclidean spaces, but not for M+N where M>1 and N>1?

And also, if we have 3 time dimensions and 1 space dimension, and the spacetime interval was

## marked as duplicate by Carl Witthoft, Kyle Kanos, Brandon Enright, Qmechanic♦Jan 28 '15 at 16:45

• Related: physics.stackexchange.com/q/10651/2451 , physics.stackexchange.com/q/43322/2451 , and links therein. – Qmechanic Jan 28 '15 at 14:43
• We actually have no idea what "time" is or how it could be defined. So time is just a word. However, there are some concepts that we relate to time, e.g. the direction of increasing entropy, that you would have to refine in your claim. – Clever Jan 28 '15 at 15:14
• @Clever To clarify, in a 2+2 Minkowski spacetime which 2 dimensions would you call space? – sashoalm Jan 28 '15 at 15:21
• I guess it would be difficult to read your question if he had one spatial dimension only... – Andre Holzner Jan 28 '15 at 15:26
• @sashoalm: I think that the term "time" we attribute to one dimension is exactly this: a term for one dimension. The fact that in SR time and space dimensions are mixed, states that time is no so special after all. I think a lot of terminology would be messed up in a 2+2 world (e.g. time-like and space-like and therefore light-like and probably causality ...). – Clever Jan 28 '15 at 16:21