Einstein's explanation

Einstein put forth two ideas:

1. The laws of physics are the same in all inertial reference frames
2. The speed of light is the same in all inertial reference frames

The second postulate contradicts common sense and everyday experience, so physicists have tested it very carefully.

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For more information

• You can read more about the notion of using binary stars to test the constancy of the speed of light
  • W. De Sitter, "On the constancy of the speed of light," Proceedings of the Royal Netherlands Academy of Arts and Sciences (or 'Koninklijke Nederlandse Akademie van Wetenschappen', aka KNAW), vol 16, p. 395-396 (1913) (Thanks to www.digitallibrary.nl
  • K. Brecher, "Is the speed of light independent of the velocity of the source?" Physical Review Letters, vol. 39, p. 1051-1054 (1977)

Copyright © Michael Richmond. This work is licensed under a Creative Commons License.