De Sitter double star experiment

The de Sitter effect was described by Willem de Sitter in 1913 and used to support the special theory of relativity against a competing 1908 emission theory by Walther Ritz that postulated a variable speed of light dependent on the velocity of the emitting object. De Sitter showed that Ritz's theory would have predicted that the orbits of binary stars would appear more eccentric than consistent with experiment and with the laws of mechanics. However, the results from astronomical observations did not support this. This was confirmed by Kenneth Brecher in 1977 by observing the x-rays spectrum. For other experiments related to special relativity, see tests of special relativity.

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