Experiments that shaped the foundation of 20th century physics
1. The Michelson–Morley Experiment (1887)Although performed near the close of the nineteenth century, the Michelson–Morley experiment laid the groundwork for the physics of the twentieth century. Albert A. Michelson and Edward W. Morley sought to uncover the “luminiferous ether,” the theoretical substance through which light waves were thought to propagate. Employing an interferometer sensitive enough to register variations as minute as a fraction of a light wavelength, they measured and contrasted the velocity of light along perpendicular axes while Earth journeyed through the cosmos.The expected shift in interference fringes never appeared. The null result undermined the ether hypothesis and directly…
