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Michelson-Morley Experiment Results

The comment to my 04/24 post about relativity had no text but just a link to a video titled:

How Einstein made the earth move


The video references a document describing the results of the Michelson-Morley experiments in the 1880's.

My response to the comment with the link:

About that Einstein video: I am confused by the description of this experiment. There are references to a change in the velocity of light by motion. That cannot happen.

Light is synchronized, perpendicular electric and magnetic fields that propagate at a fixed velocity in a vacuum. This speed does not change even with motion.
If the source moves then only the wave lengths change; they increase in the direction opposite of motion; they decrease in the direction of motion. This is red shift or blue shift.

Light does slow down when propagating in a medium, like water or air where the density affects the reduction.

This experiment conducted in air cannot detect any change in the velocity of light, unless (unlikely) the air density was not uniform.

It uses two light sources.
One source is moving at at an  angle different than the other by 90 degrees.

The motion of both sources is the accumulated motion at Earth's surface, the Earth, the Sun, the galaxy. The motion that is along the vector of the light would result in an associated change in its wave lengths.
The interferometer is comparing the light having  very slight changes in wave lengths along the two perpendicular vectors.

This experiment actually  involves  much more than just looking for a change in the velocity of light, which cannot be found here.

I am not immediately sure what should be observed. Are we sure of some of those motions?
Anyone else know?

This experiment did not really test for Earth's motion correctly because light has a fixed velocity.

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