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Re: Confirmation of Relativity



Rather than an actual experimental result, would a "thought experiment"
result do? I show my students the section of COSMOS (Carl Sagan) that
he did on relativity, and the addenda he attached to the tape series.

Shame on you! Gedanken experiments don't test any theory. I can make
a Gedanken experiment which will reveal that all green objects have
negative gravitational mass. What would that demonstrate? What is
sought here (by the student) is *evidence*. He should not be happy
with what you propose.

It shows a nice view of forshortening and curvature.

Couldn't gravitational lensing be included here as an indirect
measurement? It changes the path length of the light.

Those are not special relativistic effects; they are examples from
general relativity. Time is also dilated in a gravitational potential
well. Time runs more slowly on Earth than it does on the Moon, and
more slowly on an artificial satellite than on Earth's surface. As a
timely example, since selective availability has just been turned
off (hooray!), there are two effects observable on GPS satellites:
their clocks run more slowly due to an SR effect, and faster due to
a GR effect. Which effect do you suppose is dominant? GPS is the only
consumer product I know that depends upon GR for its function.

Leigh