http://www.youtube.com/watch?feature...&v=kZaz4UYlJ2s
Edward Witten - String theory 1/5

In this video Ed Witten explains that, according to Maxwell's theory, the speed of light is independent of the motion of the light source. That is correct but Witten would not say, and perhaps does not know, that, according to Maxwell's theory, the speed of light (as measured by the observer) VARIES WITH THE SPEED OF THE OBSERVER.

Witten further explains that at the end of the 19th century people expected the speed of light to vary with the speed of the light source (as in the throwing-a-ball-on-a-train example Witten gives) but, surprisingly, Michelson and Morley got what Maxwell had predicted - that the speed of light does not vary with the speed of the light source. This is a blatant lie of course. In that period everybody's expectations were in strict accordance with the predictions of Maxwell's theory - the speed of light is independent of the motion of the source but VARIES WITH THE SPEED OF THE OBSERVER. Yet in 1887 the null result Michelson and Morley obtained unequivocally showed that the speed of light varies with both the speed of the source and the speed of the observer, as predicted by Newton's emission theory of light:

http://www.pitt.edu/~jdnorton/papers/companion.doc
John Norton: "These efforts were long misled by an exaggeration of the importance of one experiment, the Michelson-Morley experiment, even though Einstein later had trouble recalling if he even knew of the experiment prior to his 1905 paper. This one experiment, in isolation, has little force. Its null result happened to be fully compatible with Newton's own emission theory of light. Located in the context of late 19th century electrodynamics when ether-based, wave theories of light predominated, however, it presented a serious problem that exercised the greatest theoretician of the day."

http://philsci-archive.pitt.edu/1743/2/Norton.pdf
John Norton: "In addition to his work as editor of the Einstein papers in finding source material, Stachel assembled the many small clues that reveal Einstein's serious consideration of an emission theory of light; and he gave us the crucial insight that Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity. Even today, this point needs emphasis. The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE."

Pentcho Valev