In
Project 2061: Science for All Americans (American Association
for the Advancement of Science, Washington, D.C., 1989), the
following is stated (paraphrased): If you
run away from a clock such as Big Ben at 3:00 at the speed of light,
you would never see the hands move, since the light from 3:01 would
never reach you.
One problem with this argument is that it assumes that an observer
could move at the speed of light, which is impossible. Let us ignore
this problem, however, and consider another problem with the
argument.
This argument is based on a false conceptual understanding which
assumes that the speed of light changes as the speed of the observer
changes. The problem is in the last phrase - "the light ... would
never reach you". According to the argument given, by running faster,
the relative speed of light supposedly decreases, until, when the
runner is moving at the speed of light, he or she is running "right
along with the waves", so that there is no net motion. The speed of
the light relative to the observer is supposedly zero. This is
inconsistent with one of the fundamental postulates of relativity-the
constancy of the speed of light for all observers.
Main
AP Main
Objectives
Review
In
Project 2061: Science for All Americans (American Association
for the Advancement of Science, Washington, D.C., 1989), the
following is stated (paraphrased): If you
run away from a clock such as Big Ben at 3:00 at the speed of light,
you would never see the hands move, since the light from 3:01 would
never reach you.
