LIGHTS ALL ASKEW IN THE HEAVENS

“One of the predictions made by Einstein was that, in the presence of a gravitating body, space would be bent causing light rays to take a different path than predicted by Newton’s physics. Eddington soon realized that this light deflection could be measured by looking at the positions of stars before and after a total solar eclipse. The May 29, 1919 solar eclipse was perfect for this task because of its unusual length (6 minutes) and a track that passed over countries not involved in World War I. It was at that time that Einstein’s new, but entirely obscure, theory of gravity would be pitted against that of the physics Grand Master, Sir Isaac Newton. Through the action of warped space surrounding the sun, the sun would act like a colossal lens, deflecting the images of stars near its occulted limb. 

“Calculations made with the help of Newton’s theory of gravity and motion also predicted such deflections of starlight, but by exactly one-half as much. The deflection was invisible to the human eye, but the fact that it occurred at all, and by a specific amount, was the key that led to a major revolution in physics. Some say that, were it not for this spectacular discovery, all of Einstein’s relativity theories would have languished for many more years.” 

—Technology Through Time, Issue #44: Einstein (NASA) 

“The predictive power of Einstein’s theory—the fact that it offered up a testable prediction—perhaps exercised a power over Eddington, whose admiration for the mathematical elegance of the theory caused him to believe in it deeply. He discarded the lower value coming out of Brazil, contending that the equipment was faulty, and with a slight bias toward his own fuzzy results from Africa got an average of just over 1.7 arc-seconds, matching Einstein’s predictions. It wasn’t the cleanest confirmation, but it was enough for Eddington, and it turned out to be valid. He later referred to getting these results as the greatest moment of his life.” 

—Walter Isaacson, Einstein: His Life and Universe 

This event will be celebrated in a PBS special by Brian Greene; it’s entitled Light Falls. 

My co-writer Shelly Berg and I wrote a song called “Some Kind of Einstein” for my 2018 album Math Camp; the lyrics reference the Eddington experiment. There’s a quote in them by Stephen Hawking: “It turns out to be very difficult to devise a theory to describe the universe all in one go.” Here’s the rest of that quote.  In the late 1960s, Hawking and his Cambridge friend and colleague, Roger Penrose, applied a new, complex mathematical model they had created from Einstein’s theory.