Reflections on the Eclipse
In the modern world, it is easy to forget our connection to celestial objects and how important that connection has been throughout human history.
Early Monday morning, I got my telescope out into the cold breezeway to acclimate to the temperature as I prepared to view that afternoon’s total eclipse of the sun. This was my fourth eclipse, but the excitement of seeing this remarkable event never seems to fade. This is the first time I was fortunate enough to be able to view it in my own backyard, and against all odds, here in eastern Canada it is a sunny day with no snow. Many of my friends and colleagues flew down to Texas for the event, but thundershowers obscured many viewing spots. In the meantime, I bundled up here, invited the neighbours and enjoyed the view from my yard.
I live in the countryside, but my neighbour’s porch lights are invariably on at night, so while I am often treated to a beautiful view of the Milky Way overhead, I am rarely in total darkness. The light pollution is, of course, much worse in urban areas, where even on a clear night one might hope to see only the brightest stars and planets. It is therefore easy to forget our connection to celestial objects or how important that connection has been throughout human history.
For ancient peoples, the disconnect between events on earth and in the heavens was less evident. In the well-lit city, the stars may appear like lights on a distant rooftop, but on a clear night in in the wilderness, you become a part of the sky. The stars appear to reach out and touch you, and one can almost feel the embrace of a galaxy.
Ancient mythology is full of connections to the heavens because of their impact on earthly events. In Egypt, the most significant event of the year was the annual flooding of the Nile River. The event that heralded the coming of the floods was the heliacal rising of the brightest star in the sky, Sirius. For most of the year, the star is hidden in the glare of the sun, but one morning it reappears in the dawn sky far enough away to be easily visible. This annual rising reoccurred as the Nile began to flood. Even today, the Mursi peoples of southwest Ethiopia connect the flooding of the Omo River with the heliacal setting of the stars in the Southern Cross.
Robert Zubrin
This sky–earth connection was taken to its logical extreme by the Misimay villagers in the Andes, who view the Milky Way as merely a celestial extension of the Vilcanota River, whose waters they see as circulating from the heavens to the Earth.
In the modern industrial world, few celestial events capture the popular imagination like a total eclipse of the Sun. In fact, eclipses have captured the scientific imagination ever since hominids began to try to understand and predict natural events. Before the advent of science, every mystery appears like pure magic. One can only imagine the terror induced by the sudden vanishing of the sun without warning. This is why, as soon as early astrologers could get reliable data on the sky, they tried to predict when these seemingly ominous events might occur.
As early as 600 BCE, Mesopotamian, Assyrian, and Babylonian priests recorded dates of past eclipses in an effort to look for regularities that would allow them to develop a strategy to predict when and where the next eclipse might happen.
Eclipse prediction began its modern zenith with the British polymath Edmund Halley, who successfully predicted an eclipse over England on 22 April 1715, and had even published a public broadsheet showing the anticipated path of the eclipse and the area over which totality would occur, much like the maps one can find everywhere in newspapers and online in North America this week. His prediction was remarkably accurate.
He had the good fortune to be able to rely on his friend Isaac Newton’s newly developed universal law of gravity that allowed an understanding of both the Moon’s orbit around the Earth, and the Earth’s around the Sun. But Halley also relied on ancient data that allowed one to estimate the intervals between times when the Earth, Sun, and Moon would repeat their positions in the sky. Because the Moon’s elliptical orbit around the earth is not in the same plane as the orbit of the Earth around the Sun, one must follow many cycles before positions once again precisely coincide, to allow an eclipse. This cycle lasts around 6,585 days, or around 18 years, and Halley gave this interval an ancient-sounding name, a ‘Saros.’ It is this cycle that implies that the next solar eclipse over North America will not occur until almost two decades from now. I hope I am still around to see it.
For physicists and astronomers, solar eclipses are celestial bonanzas, allowing observations of the Sun and its environs that are otherwise almost impossible. This time around, astronomers hope to use the fact that the solar cycle will be at its peak to attempt to understand why the temperatures in the corona surrounding the Sun are so much higher than on the surface of the Sun itself. But none of our modern observations today are likely to rival the famous observations of the 1919 solar eclipse, when a British expedition went to South America to check the predictions of a German-born scientist—and verified Albert Einstein’s remarkable prediction that space and time themselves are distorted by the presence of mass and energy.
There is a striking pathos in the fact that scientists from two countries that had only a year earlier been locked in a horrifying world war came together to unweave such a cosmic mystery. It demonstrates that science, at its best, unifies humanity in a way that few other human activities can. In our modern world, which also has its horrific wars, national rivalries, and ubiquitous political hatreds, it is comforting to think that—for at least 3 minutes or so—the noise and hubbub of world events was silenced for many millions, as they looked up at the sky and our myopic human vision was briefly expanded as we marvelled at this wonder of the cosmos. I hope it reminded people of how precious our brief moment in the sun really is.
