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?
In 1941, this quote by American poet Ralph Waldo Emerson inspired a young and then little-known science fiction writer to produce what is arguably the greatest science fiction story of all time.
On the planet Lagash, a group of astronomers try to warn a disbelieving public that a doomsday cult is correct and the end of the world is indeed nigh. Lagash is one of the most remarkable planets in the galaxy - it is part of a system comprising six suns, of which at least one is always in the sky. Night is unknown - or almost unknown.
The astronomers, investigating anomalies in Lagash's orbit, which threaten to overturn the recently established Law of Universal Gravitation, have made an alarming discovery. The problem with the orbit can be resolved by postulating that Lagash has a hitherto undiscovered moon, invisible in the glare of the eternal day. When the moon's orbit is calculated, the astronomers learn that it can cause an eclipse of one of the suns, the red dwarf Beta. The phenomenon can only occur with Beta alone in its hemisphere, at maximum distance from Lagash, with the moon at minimum distance - a configuration that only occurs every 2049 years. The eclipse covers the entire planet and lasts well over half a day, so that no spot on Lagash escapes being plunged into darkness.
The psychological effects on a population unused to darkness will be catastrophic - and an eclipse is imminent....
WARNING: SPOILER ALERT!
One of the reasons Nightfall is such a powerful tale is the mounting sense of terror Asimov manages to convey to his readers in his description of what is after all an everyday occurrence here on earth - the fall of dusk. He does this by the clever choice of a red dwarf as the sun that is eclipsed. He describes Beta as "glowering redly at zenith, dwarfed and evil" and makes frequent comparisons between its red light and blood. As the eclipse proceeds, the sky is described as turning "a horrible deep purple-red". It is powerful, almost apocalyptic stuff.
No less intense is the description of the claustrophobia experienced by the group of astronomers as the gloom deepens. Outside, even the insects are frightened into silence.
Few short stories manage to draw together as many diverse, thought-provoking ideas as Nightfall. Archaeological records that tell of a series of earlier civilisations, all destroyed by fire at the height of their culture; a doomsday cult that claims Lagash enters a cave every 2050 years, plunging it into darkness; and a fairground ride that has caused people to go mad and even die of fright - all this inexorably heightens the sense of impending doom.
In 1990, almost half a century after Nightfall first appeared, Asimov collaborated with Robert Silverberg, to produce a novel based on the original short story.
When two of the world's greatest SF writers team up on such a project, expectations are bound to be very high and this was possibly why Nightfall the novel met with a mixed reception. Some loved it, but many hated it, going as far as to describe it as the weakest offering from either author in a decade. IMHO, the truth lies somewhere between the two extremes.
The first two-thirds of the novel expands on the events and ideas described in the short story. The two versions are very consistent, even featuring the same characters, though with the addition of an archaeologist, who makes the crucial discoveries about the planet's past history. There are some trifling name changes - the six suns are given proper names rather than Greek letters, and for some reason the planet itself is renamed Kalgash. (We will conjecture that Kalgash is a more accurate English rendering of the planet's name, just as Peking is now usually referred to as Beijing. For simplicity, though, I will continue to use the original names.)
The last third of the novel follows events after the eclipse, as survivors who have retained their faculties try to regroup in a world rapidly reverting to feudalism. I have to agree with those who say that the ending is weak. It is true that the idea of using religious superstition to hold together a disintegrating society also appears in Asimov's Foundation Trilogy, but an open ending with the feudal leaders, cultists and scientists battling for control of Lagash would have been better.
The novel's strong points is that it paints a picture of day to day life on of world very different to Earth in some ways, yet very similar in others. It develops and draws together the same diverse ideas as the original, with a scientific community and general public reacting to events in a manner that is completely believable.
We learn that Lagash is centuries behind Earth in the sciences of astronomy, cosmology and physics, but at a similar level in terms of engineering and technology. Presumably, though, the Lagashans have not yet managed to send even an unmanned vehicle beyond their atmosphere, or they would have learned of the existence of the Stars. With gravitation such a recent discovery, though, this is hardly surprising.
We also learn something about the system to which Lagash belongs. The planet orbits a yellow sun at a distance of ten light minutes (slightly further than Earth is from the Sun), there is a binary pair of blue suns at one hundred and ten light minutes away (somewhat closer than Uranus is from Earth) and the system also comprises a red dwarf and a binary pair of white suns.
The problem with the novel is that it exposes the intriguing and unusual elements that make up the story to a scrutiny under which they cannot entirely hold up.
Just how valid is the story's central premise, that Darkness combined with the Stars will cause universal madness among a people utterly unused to such things? Is something going to cause madness simply because it has not been previously experienced and is unnatural? For example, for 99.9 percent of his history, mankind was utterly unused to flying. To man, a primate, flying is completely unnatural. Yet millions now do so every year without going mad. Even those with a fear of flying can generally tolerate it (exceptions include the former Arsenal and Netherlands footballer Dennis Bergkamp, and (alledgedly) The Good Doctor himself).
We must also question whether an advanced technological society could evolve given the handicap of a pathological fear of darkness. On Earth, after all, dependency on artificial lighting, even during daytime, has always been perfectly normal. Underground mines have existed since prehistoric times. But would Neolithic and Bronze Age man have constructed them faced with a deep-rooted phobia of entering such places and knowing that they risked instant madness were their crude illumination to fail? Without the Bronze Age, the science of metallurgy and all subsequent human advances would never have happened.
Crucial to the plot is the fact that Lagash's moon cannot be seen in the eternal daylight due to its being composed of bluish rock. Would this be the case? Earth's moon, composed of greyish rock (which will have a lower albedo), is easy to see by day. Possibly the Lagashan eye is less sensitive to relatively faint objects than the human eye (but it is curious that their eyes can dark-adapt like ours. How did this ability evolve on Lagash?).
Even if the moon cannot normally be seen, what happens during the total eclipse of Beta? Surely the moon, illuminated by the light of the other suns, would become visible. With these suns shining on it from various angles it would appear full - and at minimum distance, seven times the apparent diameter of Beta, almost certainly bright enough to drown out all but the brightest Stars. (We can rule out the possibility of Lagash itself eclipsing its moon, since one of the other suns set only four hours prior to totality.)
If only in comparison to the stunning original version, Nightfall doesn't entirely succeed as a novel and for this reason, the short story remains the definitive version.
© Christopher Seddon 2008