Sagnac
Thirteen "wavelengths" (distance a photon has to move in one of its cycles) are needed to catch up to the moving source in one revolution when moving counterclockwise, eleven are needed in the clockwise direction. Yet at any given instant there are exactly twelve in the circumference. The time needed for a cycle is exactly the same for both because they are emitted simultaneously and arrive simultaneously.
The rays move at c and -c relative to the source, but the source is moving. In the animation above what you are actually seeing is rather like the spokes of a wheel appearing to turn backwards in a movie, the eye sees a different spoke in approximately the same place as the former *. The animation was constructed with an advance of 30 degrees for the entire animation as shown by the ball.
By the principle of superposition a beat frequency naturally arises as a consequence of the blue ray travelling at v-c and the red ray travelling at v+c in the frame of the stationary observer (YOU). Use of beat frequencies is common in radio.
The time between crests is exactly the same, the distance moved is not, and since speed = distance/time, one ray must be moving faster than the other. Hence a Sagnac interferometer provides a useful device such as a fibre optic gyroscope (FOG). Thus the observer (YOU) sees c+v and c-v, but the mind is easily deceived. On the right you can see the beat frequency as it a happens, the window is alternately blue and then red once per revolution of the turntable.
Incidentally, careful consideration should be given to the pulsar phenomenon, which may well be a natural beat frequency and not an emitted frequency. There is no guarantee that what you see happening is what you think is happening.
In the following animation we have the same concept but with 4 mirrors instead of a fibre optic. The first few frames are run slowly to show how the light strikes the exact centre of the mirrors and then continues at a faster pace to trace the entire path from centre right back to centre right. This would of course not be the case in a real Sagnac interferometer which would revolve with a constant angular velocity.
In the moving frame of reference both red and blue rays travel from mirror centre to mirror centre and each travels the same distance. However, both the red ray and the blue ray travel from A to B and back to A once more, and do so in time t'A-tA , yet the blue ray has travelled a greater distance than the red ray.
In this animation the Coriolis effect is shown. Photons continue on in a straight line as the device turns beneath, giving the appearance of a curved path for the light:
In this animation of a four mirror Sagnac ring the phase is shown. Initially the phase of the two beams is necessarily locked but when the final beam-splitter is reached and the two beams combined, still in phase, one departs with velocity c+v and the other with velocity c-v. Upon reaching the detector the two beams are necessarily out of phase.
Einstein's ridiculous assertion that "the velocity of light c cannot be altered by composition with a velocity less than that of light" and his crank theories are thus disproven by reality. Georges Sagnac devised his interferometer and gave it to the world in 1913 while Einstein was developing his general theory of crackpottery. Sagnac interferometers are put into daily use in aircraft, no engineer has ever made or ever will make any use of Einstein's drivel.
To echo Newton's words said of Ptolemy, This is the story of a scientific crime. I mean a crime committed by a scientist against fellow scientists and scholars, a betrayal of the ethics and integrity of his profession that has forever deprived mankind of fundamental information about an important area of astronomy and history.
Einstein developed certain astronomical (and physical) theories and discovered that they were not consistent with observation. Instead of abandoning the theories, he deliberately fabricated observations from the theories so that he could claim that the observations prove the validity of his theories. In every scientific or scholarly setting known, this practice is called fraud, and it is a crime against science and scholarship.
Full set of 24 frames, advance 15 degrees.
Half set of 12 odd frames, advance 30 degrees, double speed.
Every third frame included, advance 45 degrees.
Set of 3 frames only. The broken spoke betrays the truth.
In this animation the broken spoke advances 85 degrees, giving the illusion of slow reversed motion where in reality we have fast forward motion. For further study look to Nyquist sampling.
This page is subject to further modification.