Relativity at highway speeds

How far would I have to drive at 70MPH in order to experience a time difference of even one minute from a stationary observer? Also, would direction of travel matter?

I feel safe in saying that you’ll never be able to drive that far; time dilation effects are not created by simple distance. There’s a reason we talk about “relativistic speeds.”

For relative speeds much less than the speed of light, the two observers measure amounts of time differing approximately one part in 2*c[sup]2[/sup]/v[sup]2[/sup]. In your case, this works out to about 5 parts in one quadrillion. To get a one-minute difference between the two observers, you’d need to drive for about 350 million years; at a rate of 70 mph, you would travel about 36 light-years in this time. You could drive to Sirius and back, twice, and still not have a full minute of difference between the two clocks.

Glad you answered that before I had a chance to. I made a mistake in my approximation and ended up off by a factor of ten million or so. Oops.