Emission theory asserts that Doppler shifting of light from a moving source represents a frequency shift with no shift in wavelength. Instead, Majorana detected wavelength changes inconsistent with emission theory. Beckmann and Mandics (1965) repeated the Michelson (1913) and Majorana (1918) moving mirror experiments in high vacuum, finding k to be less than 0.09. Although the vacuum employed was insufficient to definitively rule out extinction as the reason for their negative results, it was sufficient to make extinction highly unlikely. Light from the moving mirror passed through a Lloyd interferometer, part of the beam traveling a direct path to the photographic film, part reflecting off the Lloyd mirror. The experiment compared the speed of light hypothetically traveling at c + v from the moving mirrors, versus reflected light hypothetically traveling at c from the Lloyd mirror. Other refutations Emission theories use the Galilean transformation, according to which time coordinates are invariant when changing frames ("absolute time"). Thus the Ives–Stilwell experiment, which confirms relativistic time dilation, also refutes the emission theory of light. As shown by Howard Percy Robertson, the complete Lorentz transformation can be derived, when the Ives–Stillwell experiment is considered together with the Michelson–Morley experiment and the Kennedy–Thorndike experiment. Furthermore, quantum electrodynamics places the propagation of light in an entirely different, but still relativistic, context, which is completely incompatible with any theory that postulates a speed of light that is affected by the speed of the source. See also History of special relativity Tests of special relativity References Isaac Newton, Philosophiæ Naturalis Principia Mathematica Isaac Newton, Opticks External links de Sitter (1913) papers on binary stars as evidence against Ritz's emission theory. Special relativity Obsolete theories in physics