Hyades

Glass positive photograph of total solar eclipse, 1919

In May 1919, British physicist Arthur Eddington organised a test of Einstein’s general theory of relativity. Two Royal Society teams observed a solar eclipse from Brazil and the island of Principe off west Africa. Photographs appeared to show that the mass of the Sun had bent light from distant stars, just as Einstein had predicted. This gravitational distortion could only be observed during a total eclipse, when the Sun’s own light was masked.