Thoughts about Time

Two astrophysicists at Johns Hopkins, Richard Conn Henry (not to be confused with the other astrophysicist named Richard Henry at University of Oklahoma) and Steve Henke, designed a new calendar. With this calendar, June, March, September, and December have 31 days while all others have 30. In this way, every year, the same date falls on the same day of the week. Christmas and New Years would always fall on Sunday. The only wrinkle is that instead of a leap year giving us a day every four years, they add a week every five years. A nifty idea.

I studied general relativity with Henry during grad school. We started the semester by working through the special theory for a couple weeks with the generalized mathematics we would need for the general theory. While playing with the basics of the metric, he pointed out that the only difference between space and time in terms of calculations in the theory was a negative sign. He then mused that if we added a second negative sign, we would have the equations governing a universe with two perpendicular times. Just as we have three spatial dimensions that are independent of each other, why couldn't we have a universe with multiple times?

But what would it look like? What would it be like to live in a universe in which you could be late in one direction and early in another? Henry sent a letter to Richard Feynman and asked him what he thought it would be like to live in such a world. Feynman wrote back that he and his son had spent a weekend playing with the question, but had no good answer. So, let's see if we can do any better. What would it be like to live in such a world?