In 1887 the Michelson-Morley experiment directly proved Newton's variable speed of light. In 1921 Einstein, already a deity, declared that the experiment had proved constancy of the speed of light. Since then, physicists have been in consensus that the Michelson-Morley experiment gloriously confirms special relativity:

The New York Times, April 19, 1921: "The special relativity arose from the question of whether light had an invariable velocity in free space, he [Einstein] said. The velocity of light could only be measured relative to a body or a co-ordinate system. He sketched a co-ordinate system K to which light had a velocity C. Whether the system was in motion or not was the fundamental principle. This has been developed through the researches of Maxwell and Lorentz, the principle of the constancy of the velocity of light having been based on many of their experiments. But did it hold for only one system? he asked. He gave the example of a street and a vehicle moving on that street. If the velocity of light was C for the street was it also C for the vehicle? If a second co-ordinate system K was introduced, moving with the velocity V, did light have the velocity of C here? When the light traveled the system moved with it, so it would appear that light moved slower and the principle apparently did not hold. Many famous experiments had been made on this point. Michelson showed that relative to the moving co-ordinate system K1, the light traveled with the same velocity as relative to K, which is contrary to the above observation. How could this be reconciled? Professor Einstein asked." https://ebay.com/itm/ALBERT-EINSTEIN...r/373400655156

Brian Cox, p. 91: "...Maxwell's brilliant synthesis of the experimental results of Faraday and others strongly suggested that the speed of light should be the same for all observers. This conclusion was supported by the experimental result of Michelson and Morley, and taken at face value by Einstein.." http://www.amazon.com/Why-Does-mc2-S.../dp/0306817586

Stephen Hawking, A Brief History of Time, Chapter 2: "The special theory of relativity was very successful in explaining that the speed of light appears the same to all observers (as shown by the Michelson-Morley experiment)...." http://www.amazon.com/Brief-History-.../dp/0553380168

Neil deGrasse Tyson: "Beginning in 1905, investigations into the behavior of light got positively spooky. That year, Einstein published his special theory of relativity, in which he ratcheted up M & M's null result to an audacious level. The speed of light in empty space, he declared, is a universal constant, no matter the speed of the light-emitting source or the speed of the person doing the measuring." https://www.amazon.fr/Death-Black-Ho.../dp/039335038X

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