In 1941, Isaac Asimov published a What if? story inspired by John W. Campbell who, in turn, was inspired by the Ralph Waldo Emerson quote above. What if humanity had never seen stars? In both the short story and novel form, Nightfall proposes people would go crazy. Catastrophically crazy.
The Short Story
The short story takes place on a planet with six suns. At any given time, you can expect the six suns to light every inch of the surface. Which means the people who live there don't know what darkness is. It's an abstract concept to them. We learn early on that when these people are faced with darkness they go apeshit insane.
A group of scientists make a terrifying discovery: every two thousand years, the planet goes dark. What does this mean for a civilization who has never seen darkness? Widespread psychosis. A civilization that tears itself down. See, the darkness is scary enough, but the appearance of the stars make the people go absolutely mad. Gripped by the star-crazed madness, the people will do anything for light. They'll burn any and everything they can get their hands on.
The story scared the shit out of me. It doesn't play on the fear of darkness itself, but on the fear of "crazy" people. To be more exact, the horror element emerges from the taut suspense: you know people are going to start flipping out and you know there's nothing the main characters can do about it. The very last line of the story chilled me to the bone.
Asimov stated he was perplexed by the popularity of the story (along with Campbell's Who Goes There? and Orson Scott Card's original version of Ender's Game, it's often called the best short story in the SF genre). He had been reluctant to give the story credit, but finally did in a short stories collection. To date, the story has been anthologized almost 50 times.
In the nineties, Asimov and Robert Silverberg co-wrote a novel version. The cover of my edition claims the short story was only part of the story. They weren't kidding.
The novel begins years before the events we witnessed in the short story. We get to know many of the characters and watch them piece together the facts: a psychologist who is treating psychotic patients who have been exposed to darkness, an archaeologist who accidentally discovers several previous civilizations, all of which were burned to the ground, and an astronomer who realizes a time will come when the planet is plunged in darkness.
The catastrophe itself takes place about midway through the book and it happens more or less exactly as it happened in the short story. The last third of the book is about the aftermath, in which most of the world's survivors are irreversibly insane. At one point, a main character observes a group of crazy men desperately trying to uproot a tree. It was one of those images that will stick with me. The men had no good reason—you don't have to when you're crazy—they just wanted to pull a tree out of the ground.
You could say these people are overreacting, sure, but even Earthlings who are accustomed with nightfall have this embedded fear of the dark, which is only ignored and never cured. It isn't really that hard to buy the catastrophic events that occur.
The original title of this post was Nightfall VS Nightfall, but it wasn't fair to compare them. They are two separate entities written at two very different times. The novel won't be considered a classic, and that's shame, just because it retreads some of the same material as the short story, which is considered a classic. I suggest reading them both, starting with the short story which you can listen to at Escape Pod.