ALBERT EINSTEIN AND THE THEORY OF A TOTAL SOLAR ECLIPSE
In 1918 nobody on Earth wanted to see a total solar eclipse more than Albert Einstein did. That rare astronomical spectacle where the moon completely covers the sun could finally prove everything he imagined. Or prove he was wrong. The light from distant stars, Einstein had calculated three years earlier, was actually bending around the sun. That meant light was a physical object and could therefore be pushed or pulled.
It all worked out on paper.
Already bored? Light bending not a big deal?
Einstein wasn’t bored. The fate of his theory of general relativity depended on proving the behavior of light. He consulted astronomical charts. The 1918 total solar eclipse in America would be his next opportunity to change the world.
To some, the proof that light can change course was already, well…stupidly obvious. We see optical illusions everywhere. Objects under water aren’t really where they appear. That shimmering lake on the horizon down the road, we know, isn’t water. Images definitely can move. And change. We already know these things.
So why did Einstein decide a total solar eclipse was the key to proving something that seemed to be fact already?
The thing is, the 39-year-old physicist was working with a concept of a reality nobody had ever fully imagined. What if light itself were a physical object? And what if gravity could move that object? Energy and mass must be considered.
To mere mortal minds, this gets murkily complicated. But Einstein envisioned the speeding light from distant stars was bending as it passed by our sun’s gravity, literally changing its course through speed-of-light energy. And it wasn’t just our sun. It must be happening wherever light passed close by any massive source of energy. Our understanding of time and space, the German physicist believed, would be changed forever if his homework proved correct. And Einstein knew exactly how to test his incredible theory.
To see the stars beyond the sun, specifically the ones appearing very close around it--—and even slightly behind it—--there is but one opportunity on Earth. The scenario: Something exactly the right size has to cover the sun to block the blinding light. For Einstein’s interests, that necessary object had to be large enough to hide the sun itself but small enough to reveal the stars that appeared close to the sun’s edge. It was the light from those peripheral stars Einstein anxiously wanted to see in 1918.
Fortunately, and through sheer, almost-unbelievable coincidence, the size of the moon is a perfect match when it passes directly in front of the sun. Einstein wasn’t interested in the starlight in other parts of the sky during an eclipse. Those stars would be studied only after he saw what was happening to light passing around our sun. If light did, indeed, have the ability to be pulled or pushed, that physical evidence of time, space and energy as a workable equation really would change everything we thought we knew about the universe.
Today we all know E=MC2 as that incomprehensible equation that changed the laws of physical science. Admittedly, rather few of us actually understand the meaning of Einstein’s general relativity theory, just as people were lost by it in 1918. No matter. Not everybody on Earth needs to be an Einstein. It turned out, one was enough.
And so it happened the next total solar eclipse that would occur on Earth was the total solar eclipse that crossed America on June 8, 1918. (It was the last time a coast-to-coast total solar eclipse occurred in the U.S. mainland.) Leading scientists were dispatched to prominent American observatories to gather as much information as could be obtained during the 89 seconds of totality. Einstein himself couldn’t attend. His native Germany and World War I prevented his travel. But those scientists who made it to Oregon’s Naval Observatory and the Chamberlin Observatory in Denver had a checklist of duties planned. The positions of stars that would be around the sun that day at the time of the eclipse already were known. Maps of the night sky had long ago marked their position. Fresh observations of those stars were now recorded. (Until Einstein, nobody had thought to compare the positions of stars at night against their apparent positions during an eclipse.)
But this point was crucial. If the scientists saw the stars around the sun were in exactly the same position during the eclipse as they appeared at night, Einstein’s theory was wrong. His name would be a footnote today. The universe as everybody knows it would not be changed.
As if to set the theoretical bar impossibly high, Einstein had already calculated the gravitational distortion of light to the extent he predicted where each star would appear during the eclipse.
If the stars appeared in even a slightly different place, Einstein would still be wrong. The theory would flop.
June 8, 1918 arrived. The eclipse was expected in the U.S. by mid afternoon. Scientists fidgeting around their instrument stations paced under morning skies. It didn’t look promising. Clouds drifted over Oregon. Gray skies surrounded Denver. Then, at 2:53 p.m. the total eclipse arrived at Oregon’s Pacific shore. Skies darkened to black, and nothing was seen by anyone.
They fared worse in Denver. “The observations possible to-day were of little importance,” newspapers concluded.
Having missed this perfect opportunity, Einstein’s theory of general relativity remained still-unproven three years after it was published.
Another total solar eclipse somewhere on Earth at some future date would have to rescue and resume the mission.
Charts were consulted. The next total solar eclipse would occur on May 29, 1919, this time in western Africa.
Again Einstein was unable to attend. Again the scientists who had been dispatched to the path of totality were defeated, but this time by even worse conditions: It wasn’t merely cloudy, it was pouring rain as the moment of totality arrived.
Just as the final seconds of totality were about to end and absolute failure and despair would send the defeated observers back to their respective countries, the scientists looked up to see a brief clearing.
Right before totality ended and seconds before the downpour resumed, a single photograph was snapped that proved Einstein was right.
Naturally the public and scientific community remained hesitant to change what they had always believed. Based on a single photograph hurriedly snapped right after a downpour the world was expected to believe the physical world around them was not as it appeared? Derisive articles by scientists peppered the news. It was suggested the interpretation of the photograph from Africa had been rushed. And good scientists never rush to judgment. Scientists noted that even skeptical minds can be tempted to see only what they want to see. Results can be steered by an otherwise innocent subconscious. Picking on Einstein became popular even as crowds flocked to see this world-famous scientist, the sudden genius with the errant hair, a celebrity nobody understood. The general public, often enthralled by fantastic speculation, had difficulty accepting the unimaginable realities of Einstein’s theoretical universe. In reality, the general public was no more capable of understanding Einstein’s theory than ordinary people are today. The fact was, the public had every reason to doubt. In 1919 the official scientific acceptance of Einstein’s theoretical evidence still had not yet been granted.
It was, after all, just one, hurried photograph taken between miserable downpours.
Yet all scientists, including Einstein, were eager for the next total solar eclipse wherever it occurred. With enough scientists and enough cameras and telescopes positioned along the long path of totality, all were convinced a conclusive answer could finally be established. Once again, everybody already knew exactly where to go.
On September 21, 1922 a total solar eclipse in Australia brought crowds of scientists from several different countries, including the United States and Canada, to revisit the still-unsettled question of Einstein’s now-famous relativity equation. Personal doubts aside, the scientists knew a necessary instrument for good science is an open mind. And one photograph did confirm Einstein’s theory. A good scientist doesn’t neglect positive evidence.
Excellent viewing weather along much of the path of eclipse totality gave enough scientists exactly what they wanted. The moment of totality arrived. A multitude of photographs taken from different positions across Australia were rushed away to laboratories for analysis. Finally, a collection of well-documented, clear photographs of the precise positions of a cluster of stars whose known position had been documented prior to the eclipse would reveal the indisputable fact.
Einstein was right.
For astronomers and physicists, September 21, 1922 is a monster date in the history of science and for mankind’s understanding of the universe.
More than 90 years have passed since that day. Today, once-impossible observations gathered from distant galaxies by mind-bending technology even Einstein himself would admire continue to challenge and expand our understanding of that original, essential confirmation made that fateful September day.