(I’m writing this post early, as I so often do. For reference, today, from the author’s perspective, is July 17, 2017. In other words, it’s 5 weeks before the posting date. In that amount of time, a lot can happen, but I can guarantee one thing: it will be cloudy on August 21. Especially in the hours just after noon.)
Today is a grand day, a great time to be alive, for it is the day of the Great American Eclipse. I’m lucky—except for the part where the weather won’t cooperate—because I live in the path of totality. Some Americans will have to travel hundreds of miles to see this brief darkening of the sun; I only have to step outside. (And remember the welding glasses or whatever, but that’s a different story.)
Eclipses of any kind are a spectacle. I’ve seen a handful of lunar ones in my 33 years, but never a solar eclipse. Those of the moon, though, really are amazing, especially the redder ones. But treating them as a natural occurrence, as a simple astronomical event that boils down to a geometry problem, that’s a very modern view. In ages past, an eclipse could be taken as any number of things, many of them bad. For a writer, that can create some very fertile ground.
Strictly speaking, an eclipse is nothing more unusual than any other alignment of celestial bodies. It’s just a lot more noticeable, that’s all. The new moon is always invisible, because its dark side is facing us, but our satellite’s orbital inclination means that it often goes into its new phase above or below the sun, relative to the sky. Only rarely does it cross directly in front of the solar disk from our perspective. Conversely, it’s rare—but not quite as rare—for the moon to fall squarely in the shadow created by the Earth when it’s full.
The vagaries of orbital mechanics mean that not every eclipse is the same. Some are total, like the one today, where the shadowing body completely covers the sun. For a solar eclipse, that means the moon is right between us and the sun—as viewed by certain parts of the world—and we’ll have two or three minutes of darkness along a long, narrow path. On the flip side, lunar eclipses are viewable by many more people, as we are the ones doing the shadowing.
Another possibility is the partial eclipse, where the alignment doesn’t quite work out perfectly; people outside of the path of totality today will only get a partial solar eclipse, and that track is so narrow that my aunt, who lives less than 15 miles to the south, is on its uncertain edge. Or you might get an annular solar eclipse, where the moon is at its apogee (farthest point in its orbit), so it isn’t quite big enough to cover the whole sun, instead leaving a blinding ring. And then there’s the penumbral lunar eclipse, essentially a mirrored version of the annular; in this case, the moon doesn’t go through the Earth’s full shadow, and most people barely even notice anything’s wrong.
However it happens, the eclipse is an astronomical eventuality. Our moon is big enough and close enough to cover the whole sun, so it’s only natural that we have solar eclipses. (On Mars, it wouldn’t work, because Phobos and Deimos are too tiny. Instead, you’d have transits, similar to the transit of Venus a few years ago.) Similarly, the moon is close enough to fall completely within its primary’s shadow on some occasions, so lunar eclipses were always going to happen.
These events are regular, precise. We can predict them years, even centuries in advance. Gravity and orbital mechanics give alignments a clockwork rhythm that can only change if acted upon by an outside body.
Days of old
In earlier days, some people saw a much different outside body at work in the heavens. Even once a culture reaches a level of mathematical and astronomical advancement where eclipses become predictable, that doesn’t mean the average person isn’t going to continue seeing them as portents. How many people believe in astrology today?
And let’s face it: an eclipse, if you don’t really know what’s going on, might be scary. Here’s the sun disappearing before our very eyes. Or the moon. Or, if it’s a particularly colorful lunar eclipse, then the moon isn’t vanishing, but turning red. You know, the color of blood. Somebody who doesn’t understand orbits and geometry would be well inclined to think something strange is going on.
Writers of fantasy and historical fiction can use this to great effect, because a rare event like an eclipse is a perfect catalyst for change and conflict. People might see it as an omen, a sign of impending doom. Then, seeing it, they might be moved to bring about the doom themselves. Seven minutes of darkness—the most we on Earth can get—might not be too bad, but a fantasy world with a larger moon may have solar eclipses that last for an hour or more, like our lunar eclipses today. That could be enough time to unnerve even the hardiest souls.
Science fiction can get into the act here, too, as in Isaac Asimov’s Nightfall. If a culture only sees an eclipse once every thousand years or so, then even the memory of the event might be forgotten by the next time it comes around. And then what happens? In the same vein, the eclipse of Pitch Black releases the horrors of that story; working that out provides a good mystery to be solved, while the partial phase offers a practical method of building tension.
Beyond the psychological effects and theological implications of an eclipse, they work well in any case where astronomy and the predictive power of science play a role. Recall, if you will, the famous story of Columbus using a known upcoming eclipse as a way to scare an indigenous culture that lacked the knowledge of its arrival. Someone who has that knowledge can very easily lord it over those who do not, which sets up potential conflicts—or provides a way out of them. “Release me, or I will take away the sun” works as a threat, if the people you’re threatening can’t be sure the sun won’t come back.
In fantasy, eclipses can even fit into the backstory. The titular character of my novel Nocturne was born during a solar eclipse (I wrote the book because of the one today, in fact), and that special quality, combined with the peculiar magic system of the setting, provides most of the forward movement of the story. On a more epic level, if fantasy gods wander the land, one of them might have the power to make his own eclipses. A good way of keeping the peasants and worshippers in line, wouldn’t you say?
However you do it, treating an eclipse as something amiss in the heavens works a lot better for a story than assuming it’s a normal celestial occurrence. Yes, they happen. Yes, they’re regular. But if they’re unexpected, then they can be so much more useful. But that’s true of science in general, at least when you start melding it with fantasy. The whole purpose of science is to explain the world in a rational manner, but fantasy is almost the antithesis of rationality. So, by keeping eclipses mysterious, momentous, portentous occasions, we let them stay in the realm of fantasy. For today, I think that’s a good thing.