Lorents transform for time
t'=(t-xv/c^2)gamma differs from Galilean
t'=t not only by relativistic gamma=1/sqrt(1-v^2/c^2) factor but by finiteness of speed of light c. This makes the factor (t-xv/c^2) for comparison of clocks separated by some distance x and moving with relative velocity v to depend on the direction of relative motion. If two observers are at the same point (x=0) then t'=t gamma. If not, then "on top" of relativistic time dilation you have additional "apparent" slow down of each other clocks (due to finite speed of light signal) when two observers move away from each other, and "apparent" speeding up of each other clocks when observers move toward each other. If one observer moves away and then returnes back, this effect vanishes and only relativistic gamma factor remains - this is what is called relativistic time dilation.

• Forgive me but my maths skills are not great - highvoltage - June 29, 2001 - 05:37 UTC
  • Gamma =1/(1-v^2/c^2), Galilean = Lorents at c=infinity. - alexander - July 3, 2001 - 01:20 UTC