How Einstein Became the First Science SuperstarRoundup
tags: Albert Einstein, science history, astronomers
Ron Cowen is the author of “Gravity’s Century: From Einstein’s Eclipse to Images of Black Holes.”
Early in 1919, two teams of British astronomers embarked on a journey to the far reaches of the planet to observe a solar eclipse. Nearly eight months later, on Nov. 6, 1919, the teams presented their findings before a packed audience of scientists in London. Their announcement changed forever how humans view the universe.
The teams’ report, coming less than a year after the end of World War I, was noteworthy for another reason: It may have helped heal the wounds of war. The British eclipse expedition was designed to test a new theory of gravity proposed by Albert Einstein, a German-born scientist who had published his work behind enemy lines. If the British proved him right, his theory would topple that of Isaac Newton, a founding father of modern scientific thought and a national hero in Britain.
Newton had viewed gravity as a force that acts across space, pulling massive bodies together. Einstein replaced that notion with the radical proposition that gravity is space. Rather than stiff and immutable as the floorboards of a stage, space and time, he said, jiggles like jelly. A massive body dents this jiggly space-time much the way a lead weight sags a sheet of rubber. Earth is attracted to the sun not because of a force but because the sun has dimpled the space-time through which our planet must travel.
As early as 1911, Einstein had suggested a way to verify his outlandish proposal, known as the general theory of relativity. If a body is massive enough — like the sun — scientists should be able to observe the curved or bent path of all objects traveling in its vicinity, even particles of starlight. Through a telescope, the bending of starlight would show up as a change in the apparent position of the star compared with its position when the sun was in another part of the sky.
Under ordinary conditions, attempting such an observation would be folly. The blinding light of the solar disk would completely swamp the much fainter light from surrounding stars. But the stars pop into view during those rare times and places when the clockwork motion of the solar system places the moon directly between the sun and Earth.
Beginning in 1912, several attempts to search for Einstein’s gravitational light-bending during a solar eclipse had failed, mainly because of bad weather. But the Great War also played a role. The German astronomer Erwin Finlay Freundlich had just arrived in the Crimea to study the solar eclipse of Aug. 21, 1914, when the war broke out. He and his associates were promptly interned in Russia as spies and their equipment was confiscated.