This PDF from the New York Times archives, dated 9 November 1919, is simply wonderful for its “in the moment” glimpse into the state of physics and astronomy at that time. Some obscure physicist that no one outside scientific circles had ever heard of, named Albert Einstein, had published a theory so esoteric that even he admitted that “there were not more than twelve persons in the whole world who would understand it.”
At the time, Newtonian physics prevailed, and this new theory of relativity was a bit out of left field. Not only that, but relativity made nearly the same predictions as Newtonian physics in most instances of gravity and light behaviors. The differences were so minute that with the scientific instruments available at the time, making measurements fine enough to prove one theory or the other was impossible.
Sir Frank Watson Dyson, Astronomer Royal of Britain, conceived in 1917 the perfect experiment to resolve the issue. A total solar eclipse on May 29, 1919, would occur just as the sun was crossing the bright Hyades star cluster. Dyson realized that the light from the stars would have to pass through the sun’s gravitational field on its way to Earth, yet would be visible due to the darkness of the eclipse. This would allow accurate measurements of the stars’ gravity-shifted positions in the sky.
Though conceived by Dyson, the experiment was performed by Sir Arthur Eddington. First, he measured the “true” positions of the stars in question during January and February of that year. Then he took part in an expedition to the island of Principe (off the west coast of Africa) to measure the stars again as their light was viewed through the sun’s gravitational lens during the eclipse. A second expedition was sent to Brazil to make the same measurements, in case of cloudy skies over Principe. Both expeditions had clear skies, and both took several photos and a bunch of data during the six-minute eclipse. Eddington returned to England to analyze the data, which conclusively proved that Einstein’s prediction was correct. He announced his findings on 6 November 1919, and within the next few days, that obscure physicist was on front pages around the world, including the New York Times.
Reading this PDF snapshot from the archives is a little brain-bending, because it so clearly illustrates how cutting edge Einstein’s theory was. Yet one century later, relativity is taught to high school students, and gravitational lensing is now one of the most powerful and oft-used tools in astrophysicists’ toolboxes.
Makes one wonder what freaky, esoteric, so-out-there-that-only-twelve-people-can-understand-it theory is floating around right now, waiting to be proven as one of the foundational theories of the universe, and taught to grade school kids in the year 2119.
(Hat tip to Alma for the PDF.)