1.4 Introducing Gamma (Special Relativity)
Description
This article is from the Relativity and FTL Travel FAQ, by Jason W. Hinson jason@physicsguy.com with numerous contributions by others.
1.4 Introducing Gamma (Special Relativity)
Now, the closer one gets to the speed of light with respect to an
observer, the slower ones clock ticks and the shorter ones meter stick will
be in the frame of reference of that observer. The factor which determines
the amount of length contraction and time dilation is called gamma.
Gamma for an object moving with speed v in your frame of reference is
defined as
(Eq 1:5)
gamma = 1 / (1 - v^2/c^2)^0.5
For our train (for which v = 0.6 c in your frame of reference), gamma is
1.25 in your frame. Lengths will be contracted and time dilated (as seen by
you--the outside observer) by a factor of 1/gamma = 0.8. That is what we
demonstrated in our example by showing that the difference in measured times
was 10 seconds for you (off the train) and 8 seconds for me (on the train)
in your point of view. Gamma is obviously an important number in relativity,
and it will appear as we discuss other consequences of the theory (including
the effects of special relativity on energy and momentum considerations).
Continue to:
My Books
