Our universe has 4 dimensions, 3 spacial and 1 temporal. We can add another spacial dimension and use math to explore it. I cannot think of any reason why we cannot add add another temporal dimension in the same way. So, what would a universe with 2 temporal dimensions be like?

These are some thought I had about physics in 2 temporal dimensions.

With one spacial dimension, forwards is the only movement possible. With two spacial dimensions, movement in many different ways is possible. It would follow then that with two temporal dimensions time travel in many different 'directions' would be possible.

The formula for velocity is displacement/time. With two times, how would velocity be effected? What would happen to light, which must travel at a constant speed?

Frankly, I have no idea a universe with 2 times is like, but I very much would like to know.

  • $\begingroup$ I think the answer to this question will depend heavily on what notion of time you intend to generalise. Depending on your view of physics time can play anything from a central role, to a fringe one as an emergent phenomenon, or even be a mere illusion. $\endgroup$ Jan 4 '14 at 20:50
  • $\begingroup$ Possible duplicates: physics.stackexchange.com/q/43322/2451 and links therein. $\endgroup$
    – Qmechanic
    Jan 4 '14 at 21:24

Not so much an answer to your question but you might want to check out 2T physics, the work of Itzhak Bars et. al., e.g.,




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