1.Albert Michelsonin ja Edward Morleyn suorittama koe, jonka tulokset valonnopeudesta olivat lähtökohta Einsteinin suhteellisuusteorialle
1.a celebrated experiment conducted by Albert Michelson and Edward Morley; their failure to detect any influence of the earth's motion on the velocity of light was the starting point for Einstein's theory of relativity