Nightfall

(Spoilers for a 76 year old Isaac Asimov story, which you can read here for some reason.)

"Nightfall" is one of my favorite Asimov stories. It's set on an alien planet in a system with six suns, arranged so that at least one is always up. Consequently, the people of this planet never know night. What drives the action is the discovery of a moon (invisible due to the constant sunlight) that astronomers predict will eclipse a sun when all the others have set. The effect would be sudden, inescapable darkness, which they fear will drive people mad (and may have led to past catastrophes).

This story has been on my mind since a little before our solar eclipse. I had heard repeatedly that a total solar eclipse is an event unlike any other, that everyone should try to experience one at some point during their lives. But although some say totality can be drop-to-your-knees-and-weep life-changing, there is as far as I know no evidence of totality-induced civilization-wide collapse. Of course, we experience night daily, so sudden darkness is not as extraordinary for us.

What is it about a total solar eclipse that inspires such numinous feeling, then? Having stood within the moon's umbral gloom for slightly more than two minutes, I can offer my own perspective.

On Sunday, August 20, I traveled to Greenville, South Carolina with a friend and his family, who had family in the area willing to put us up for two nights. The drive down to Greenville from Maryland took about 11 hours. 11 hours of tedium and traffic for 2 minutes of totality—an easy choice for most, whatever that choice may be.

That evening, I passed out eclipse glasses to those who needed them and jury-rigged a solar filter onto my binoculars with index cards and masking tape. As the resident astronomy expert, I had been told by multiple eclipse veterans that it was my responsibility to do dry runs of totality so the uninitiated would be prepared for the moment. Instead we watched Game of Thrones and considered our return travel plans in light of the awful traffic coming down.

The day of, August 21, we found a nearby baseball diamond and set up our equipment about fifteen minutes before the start of the partial phase. A partial solar eclipse is a weird and cool but ultimately very detached phenomenon. You can't (or shouldn't) look directly at the sun, so watching the moon's shadow creep across its face requires filters or those eclipse glasses you've heard way too much about by now.

Through them, there was only the waning orange disc of the sun and blackness—the black of the moon, the black of sky, the black of anything else we might try to look at. Witnessing a partial eclipse was like looking through an insufficiently detailed virtual reality environment. On top of that, up until about 80% obscuration, there was very little change in our surroundings to indicate that anything was up.

But the orange disc inexorably slid into a crescent, which served as a visceral countdown to the main event: totality.

At about fifteen minutes before second contact, with the sun a thin wedge, we began to notice that it was substantially cooler out and strangely dim. The sun was still a blazing fireball in a bright blue sky, but the whole scene was a few shades darker, as if seen through sunglasses. Unfortunately, we didn't have an opportunity to see much in the way of strange shadows where we were.

As the moon reduced the sun to an arc of light, I watched through my binoculars until the orange shriveled to nothing, leaving only black. Then I looked up and experienced totality.

There's something of a twist in "Nightfall," which is that it's not night that drives people mad. In the story, they had been preparing for it. In fact, a minute or two in a totally dark room was akin to an amusement park ride for us—thrilling and hair-raising, maybe too much for some, but ultimately pretty safe.

What drove them mad was a phenomenon they were utterly unprepared for, which shattered their conception of the world and forced them to pick up the pieces.

When night finally fell, the stars came out. Except in myth, their world had consisted entirely of one planet and its attendant suns. But each pinprick of light against the black was another sun, another possible world. Each twinkling tear in the curtain of night let them peek into a much, much larger universe, one too big for their minds to bear. So they went mad instead.

I knew intellectually—from descriptions and pictures—what totality was going to be like. None of that prepared me for the moment itself, when the whole solar system was laid out before me.

Night fell and the stars came out, yes. And birds and bugs acted up. And the sun disappeared.

But here's what stuck with me. I don't remember all that many stars and it was never truly dark out. After gaping at the eclipsed sun for a moment, I saw Jupiter to the east and Venus to the west. They flanked the sun, and I could draw a straight line through all three of them. That line is the ecliptic plane, the disc of our solar system. But in the middle, instead of a sun, there was a hole in the sky—the moon. It, too, lay in that plane, along with me staring up at it all.

With the moon intercepting the light of day, the sun's faint outer atmosphere became visible. For most of our lives, the sun is a featureless glare we have to avoid. We only glimpse it during sunrise and sunset. But even then, the beauty of dawn and twilight is in the intermingling of sun and sky; it's never just you and the sun.

But the corona is the crown of the sun. By eye alone I could see exquisite detail and structure in the threaded, incandescent layers that were hidden from me a moment before. All this made the sun very real—not an untouchable brilliance, not a puddle of mixing reds, not a perfect orange disc against the black, but a giant ball of plasma reaching out to me. And it sat in the middle of a vast solar solar system of planets, with me on a tiny blue one hurtling around it.

Then it was over. The eclipse didn't fade away like a half-remembered dream. It just ended. There were a few seconds of twinkling at the edge of the black and then daylight returned, and the sun and planets and solar system were gone.

The initial seed for Asimov's "Nightfall," so the story goes, was a conversation between him and his editor, John W. Campbell. There's a line in a Ralph Waldo Emerson essay that reads, "If the stars should appear one night in a thousand years, how would men believe and adore, and preserve for many generations the remembrance of the city of God!" Campbell gave this line to Asimov essentially as a prompt, telling him he thought "men would go mad" instead.

And indeed, that's what happens. The short story ends with the main characters holed up in a fortified observatory, watching a crimson glow on the horizon that is not the return of the sun, but a city aflame.

So Asimov and Campbell are pretty cynical about our capacity to cope with a terrifyingly large world. By nature I share that perspective, and a gander at my Twitter feed seems to confirm the validity of such cynicism. While we are still stuck on this pale blue dot, the complexity of the world has grown dramatically in the last couple centuries.

We find ourselves unable to confront the reality of global warming, to the extent that some of us deny it while most of us pretend everything will work out somehow. Our societies have become increasingly interconnected and pluralistic, leading many to retreat into xenophobia that is at best ugly and at worst fiery and violent. Given all that, it doesn't seem unreasonable to imagine that a revelation as world-expanding as "Nightfall"'s might just unhinge us permanently and end our little experiment with civilization.

After totality ended, we stuck around for a bit chatting with others who had come to our baseball diamond, then eventually made our way back to my friend's family's place. There, I was told that a neighboring family had questions for the astronomer on location. Apparently they meant me.

I wandered over and met with a five year old and his mom and dad. The mom asked questions about the eclipse—the why of shadow bands and of different eclipse paths. Then the kid launched into questions about dwarf planets. He wanted to see all of them, so I showed him pictures of Pluto and Charon taken from New Horizons and Ceres from Dawn, and then explained that because dwarf planets are so small and so far away, we needed to build bigger telescopes and faster probes before we could see the rest of them. After that I managed to satisfy his curiosity with some moons, including my favorite Enceladus (about which I've been writing a post since my planetary science course in 2015).

The mom wanted to make sure I didn't dumb down my explanations for her son. The dad wanted to know if there was alien life out there (either on some moon in the solar system or on an exoplanet light years away) and when we were going to Mars.

I talked with the young family for about half an hour, answering questions and trying to feed their enthusiasm with as much knowledge as I could. Talking with strangers is not an activity that comes naturally to me (understatement), but after two semesters as a teaching assistant leading discussions and labs, I have come to enjoy this type of interaction.

What I find particularly heartening about being an ambassador for astronomy is the sheer wonder and curiosity we can have for the enormous, mind-blowing universe our telescopes have revealed. People are drawn to strange new worlds and the idea that we might someday have a home beyond Earth. Maybe fear and madness are natural and understandable reactions to a world too big to wrap our heads around, but they're not the only possible responses. How do we cultivate such wonder? How do we embrace curiosity so that it extends beyond pretty pictures and to all the unbearable complexity we are faced with?

I don't know the answer to that question. Maybe it takes witnessing once in a lifetime astronomical marvels. (Helpfully, if you missed this one, the US has another in seven years.) In the meantime, maybe read some imaginative, thoughtful, mind-expanding science fiction. For the foreseeable future, that's as close as we can get to a larger world.