Off topic - Michelson-Morley bar discussion

[Doug Sweetser]

Hello:

This topic came up after the BLU meeting at the Cambridge Brewery, and
I forgot to make this point.  Special relativity should always be
presented as those things that change, and those things that do not
change.  For whatever reason, certain experiments only discuss the
things that change, while others only describe those that are
invariant.  A complete picture of what is going on always discusses
both.  In the Michelson-Morley experiment where light travels along
two paths perpendicular to each other, what is always discussed is how
the speed of light is exactly the same, even though with the spin
Earth whirling around the Sun going around the galaxy moving rapidly
way from all others, no change in the velocity of light is measured.
The wavelength and the frequency  do change in a precise way.  One
will go up, the other down, and the product which gives the speed
remains the same.

doug