@mokazemi Interestingly, measuring intervals in #spacetime works something like this in the special theory of relativity, where the "proper time" between two events separated in space by dx and in time by dt is dT^2 = dt^2 - (dx/c)^2. When dx=c*dt, dT=0.

Physically dT represents the time experienced by someone traveling between the two events at a constant velocity (when it's not negative). When the velocity approaches the speed of light, time dilation makes the elapsed proper time approach zero.

#relativity #specialRelativity