The Eclipse Photo That Made Einstein Famous

In 1919, a total solar eclipse helped redefine gravity. Albert Einstein’s theory of general relativity, published in 1915, defined gravity as the influence of massive objects, like planets and stars, curving space around them. This was very different from the way Isaac Newton had defined gravity over 200 years earlier: Newton described an attracting force that kept planets and stars in orbit with each other. If Einstein was right, then light would also bend near massive objects. And in 1919, two British expeditions set out to test it by photographing a total solar eclipse.