Copyright © 1999 David E. Rutherford
All Rights Reserved
We can use similar methods to find the comparison of elapsed times in two
reference frames. The frames are in uniform motion with four-velocity
relative
to each other. An observer at rest in the primed frame makes his time
measurement,
, at the same place in his frame, so
. Using
Eqs. (22), we have
and
But since we are comparing only time measurements, we have
or
The coordinate
in this case, is the proper
time,
.
The coordinate
is the unprimed observer's improper measurement of the elapsed time in
the primed frame. This constitutes a dilation of time. In other words, an
observer in the unprimed frame says that the rate at which clocks run in
the primed frame is slower than in his own frame. Again, the effect is
reciprocal.
Copyright © 1999 David E. Rutherford
All Rights Reserved
E-mail: drutherford@softcom.net