Nightfall

by Isaac Asimov

  “Have you considered simply suppressing your findings?”

  Beenay looked astonished. “You know I couldn’t do that!”

  “Yes. Yes, I do know. But I had to find out whether you were thinking of it.”

  “Whether I was thinking of the unthinkable? No, of course not. It never entered my mind. But what am I going to do, Theremon? —I suppose I could just throw all the papers away and pretend I never looked into the whole subject. But that would be monstrous. So what it comes down to is, I have a choice between violating my own scientific conscience and ruining Athor. Ruining the man I look upon not simply as the head of my profession but as my own philosophical mentor.”

  “He can’t have been much of a mentor, then.”

  The astronomer’s eyes widened in astonishment and fury. “What are you saying, Theremon!”

  “Easy. Easy.” Theremon spread his hands wide in a conciliatory gesture. “It seems to me you’re being awfully condescending to him, Beenay. If Athor’s really the great man you think he is, he’s not going to put his own reputation above scientific truth. Do you see what I mean? Athor’s theory is not cast-iron. No theory is and there is always room for improvement. Isn’t that so? Science is constructed out of approximations that gradually approach the truth, you told me a long time back, and I’ve never forgotten it. Well, that means all theories are subject to constant testing and modification, doesn’t it? And if it eventually turns out that they’re not quite close enough to the truth, they need to be replaced by something that’s closer. Right, Beenay? Right?”

  Beenay was trembling now. He looked very pale.

  “Could you get me another drink, Theremon?”

  “No. Listen to me: there’s more. You say that you’re so worried about Athor—he’s old; I suppose he’s pretty frail—that you don’t have the heart to tell him you’ve found a flaw in his theory. All right. That’s a decent and loving position to take. But think about this, will you? If calculating the orbit of Kalgash is all that important, somebody else is likely to stumble across the same flaw in Athor’s theory sooner or later, and that other person isn’t likely to be as tactful in letting Athor know about it as you’d be. He might even be a professional rival of Athor’s, an outright enemy of his—every scientist has enemies, you’ve told me so plenty of times. Wouldn’t it be better for you to go to Athor and tell him, gently, carefully, of what you’ve discovered, than for him to find out about it one morning in the Chronicle?”

  “Yes,” Beenay whispered. “You’re completely right.”

  “You’ll go to him, then?”

  “Yes. Yes. I have to, I suppose.” Beenay bit his lip. “I feel miserable about this, Theremon. I feel like a murderer.”

  “I know you do. But it isn’t Athor you’ll be murdering, it’s a defective theory. Defective theories must never be allowed to persist. You owe it to Athor as well as yourself to let the truth emerge.” Theremon hesitated. A sudden startling new idea had occurred to him. “Of course, there’s one other possibility. I’m only a layman, you know, and you’ll probably laugh. —Is there any chance that the Theory of Gravitation might be correct despite everything, and that the computer’s figures for Kalgash’s orbit are right also, and that some other factor entirely, something altogether unknown, might be responsible for the discrepancy in your result?”

  “That could be, I suppose,” said Beenay in a flat, dispirited tone. “But once you begin dragging in mysterious unknown factors, you begin to move into the realm of fantasy. —I’ll give you an example. Let’s say there’s an invisible seventh sun out there—it’s got mass, it exerts gravitational force, but we simply can’t see it. Since we don’t know it’s there, we haven’t plugged it into our gravitational calculations, and so the figures come out cockeyed. Is that what you mean?”

  “Well, why not?”

  “Why not five invisible suns, then? Why not fifty? Why not an invisible giant who pushes planets around according to his whims? Why not a huge dragon whose breath deflects Kalgash from its proper path? We can’t disprove it, can we? When you start in with why nots, Theremon, anything becomes possible, and then nothing makes any sense. At least not to me. I can only deal with what I know is real. You may be right that there’s an unknown factor, and that therefore the gravitational laws aren’t invalid. I certainly hope so. But I can’t do serious work on that basis. All I can do is go to Athor, which I will, I promise you that, and tell him what the computer has told me. I don’t dare suggest to him or anybody that I blame the whole mess on a hitherto undiscovered ‘unknown factor.’ Otherwise I’d sound just as crazy as the Apostles of Flame, who claim to know all sorts of mystic revelations. —Theremon, I really want that other drink now.”

  “Yes. All right. And speaking of the Apostles of Flame—”

  “You want a statement from me, I remember.” Beenay passed a hand wearily in front of his face. “Yes. Yes. I won’t let you down. You’ve been a tremendous help to me this evening. —What is it exactly that the Apostles have said now? I forget.”

  “It was Mondior 71,” said Theremon. “The Grand High Mumbo-Jumbo himself. What he said was—let me think—that the time is very near when the gods intend to purge the world of sin, that he can calculate the exact day, even the exact hour, when doom will arrive.”

  Beenay groaned. “So what’s new about that? Isn’t that what they’ve been saying for years?”

  “Yes, but they’re starting to hand out more of the gory details now. It’s the notion of the Apostles, you know, that this won’t be the first time the world has been destroyed. They teach that the gods have deliberately made mankind imperfect, as a test, and that they have given us a single year—one of their divine years, not one of our little ones—in which to shape up. That’s called a Year of Godliness, and it’s exactly two thousand and forty-nine of our years long. Again and again, when the Year of Godliness has ended, the gods have discovered that we’re still wicked and sinful, and so they have destroyed the world by sending down heavenly flames from holy places in the sky that are known as Stars. So say the Apostles, anyway.”

  “Stars?” Beenay said. “Does he mean the suns?”

  “No, Stars. Mondior says that the Stars are specifically different from the six suns. —Haven’t you ever paid any attention to this stuff, Beenay?”

  “No. Why in the world should I?”

  “Well, in any event, when the Year of Godliness ends and nothing on Kalgash has improved, morally speaking, these Stars drop some sort of holy fire on us and burn us up. Mondior says this has happened any number of times. But each time it does, the gods are merciful, or at least a faction among them is: every time the world is destroyed, the kinder gods prevail over the sterner ones and humanity is given one more chance. And so the godliest of the survivors are rescued from the holocaust and a new deadline is set: mankind gets another two thousand and forty-nine years to cast off its evil ways. The time is almost up again, says Mondior. It’s just under two thousand and forty-eight years since the last cataclysm. In something like fourteen months the suns will all disappear and these hideous Stars of his will shoot flame down out of a black sky to wipe out the wicked. Next year on Theptar nineteenth, to be specific.”

  “Fourteen months,” Beenay said in a musing way. “The nineteenth of Theptar. He’s very precise about it, isn’t he? I suppose he knows the exact time of day it’ll happen, too.”

  “So he says, yes. That’s why I’d like a statement from somebody connected with the Observatory, preferably you. Mondior’s latest announcement is that the exact time of the catastrophe can be calculated scientifically—that it isn’t simply something that’s set forth as dogma in the Book of Revelations, but that it’s subject to the same sort of computation that astronomers employ when—when—”

  Theremon faltered and halted.

  “When we calculate the orbital motions of the suns and the world?” Beenay asked acidly.

  “Well, yes,” Theremon said, looking abashed.

 
; “Then maybe there’s hope for the world after all, if the Apostles can’t do any better job of it than we do.”

  “I need a statement, Beenay.”

  “Yes. I realize that.” The next round of drinks had arrived. Beenay wrapped his hand around his glass. “Try this,” he said after a moment. “ ‘The main task of science is to separate truth from untruth, in the hope of revealing the way the universe really works. Putting truth to work in the service of untruth is not what we at the university think of as the scientific way. We are capable now of predicting the movements of the suns in the heavens, yes—but even if we use our best computer, we are no closer than we ever were to being able to foretell the will of the gods. Nor will we ever be, I suspect.’—How’s that?”

  “Perfect,” Theremon said. “Let’s see if I’ve got it. ‘The main task of science is to separate truth from untruth, in the hope of—of—’ What came next, Beenay?”

  Beenay repeated the whole thing word for word, as though he had memorized it hours before.

  Then he drained his third drink at a single astonishing long gulp.

  And then he stood up, smiled for the first time all evening, and fell flat on his face.

  [9]

  Athor 77’s eyes narrowed, and he scrutinized the little sheaf of printouts lying before him on his desk as though they were maps of continents that no one had ever known existed.

  He was very calm. He was amazed at how calm he was.

  “Very interesting, Beenay,” he said slowly. “Very, very interesting.”

  “Of course, sir, there’s always the possibility that not only have I made some crucial error in fundamental assumptions, but that Yimot and Faro also—”

  “All three of you getting your basic postulates wrong? No, Beenay. I think not.”

  “I just wanted to indicate that the possibility exists.”

  “Please,” Athor said. “Let me think.”

  It was midmorning. Onos in full glory blazed in the sky that was visible through the tall window of the Observatory director’s office. Dovim was barely apparent, a small hard red dot of light, making a high northerly transit.

  Athor fingered the papers, moving them about again and again on his desk. And moved them yet again. How strange to be taking this so easily, he thought. Beenay was the one who seemed all wrought up over it; he himself had scarcely reacted at all.

  Perhaps I’m in shock, Athor speculated.

  “Over here, sir, I have the orbit of Kalgash according to the generally accepted almanac computation. And here, on the printout, we have the orbital prediction that the new computer—”

  “Please, Beenay. I said I wanted to think.”

  Beenay nodded jerkily. Athor smiled at him, not an easy thing for Athor to do. The formidable head of the Observatory, a tall, thin, commanding-looking man with an impressive shock of thick white hair, had allowed himself so long ago to slip into the role of Austere Giant of Science that it was difficult for him to unbend and permit himself to show ordinary human responses. At least, it was difficult for him while he was here at the Observatory, where everyone looked upon him as a sort of demigod. At home, with his wife, with his children, especially with his noisy flock of grandchildren, it was a different matter.

  So Universal Gravitation wasn’t quite right, was it?

  No! No, that was impossible! Every atom of common sense in him protested at the thought. The concept of Universal Gravitation was fundamental to any comprehension of the structure of the universe, Athor was certain. Athor knew. It was too clean, too logical, too beautiful, to be wrong.

  Take Universal Gravitation away, and the entire logic of the cosmos dissolved into chaos.

  Inconceivable. Unimaginable.

  But these figures—this damnable printout of Beenay’s—

  “I can see you’re angry, sir.” Beenay, chattering again! “And I want to tell you, I can quite understand it—the way this must hit you—anyone would be angry, having his life’s work jeopardized this way—”

  “Beenay—”

  “Just let me say, sir, that I’d give anything not to have had to bring you this today. I know you’re furious with me for coming in here with this, but I can only say that I thought long and hard before I did. What I really wanted to do was burn everything and forget I ever got started on any of this. I’m appalled that I found what I did, and appalled that I was the one who—”

  “Beenay,” Athor said again, in his most ominous voice.

  “Sir?”

  “I am furious with you, yes. But not for the reason you think.”

  “Sir?”

  “Number one, I’m annoyed at the way you’ve been babbling at me, when all I want to do is sit here and quietly work through the implications of these papers you’ve just tossed at me. Number two, and much more important, I’m absolutely outraged that you’d have hesitated for so much as a moment to bring me your findings. Why did you wait so long?”

  “It was only yesterday that I finished double-checking.”

  “Yesterday! Then you should have been in here yesterday! Do you really mean to say, Beenay, that you seriously considered suppressing all this? That you would simply have tossed your results away and said nothing?”

  “No, sir,” said Beenay miserably. “I never actually thought about doing that.”

  “Well, that’s a blessing. Tell me, man, do you think I’m so enamored of my own beautiful theory that I’d want one of my most gifted associates to shield me from the unpleasant news that the theory’s got a flaw in it?”

  “No, sir. Of course not.”

  “Then why didn’t you come running in here with the news the moment you were sure you were right?”

  “Because—because, sir—” Beenay looked as though he wanted to vanish into the carpet. “Because I knew how upset you’d be. Because I thought you might—you might be so upset that your health would be affected. So I held back, I talked to a couple of friends, I thought through my own position on all of this, and I came to see that I really had no choice, I had to tell you that the Theory of Univer—”

  “So you really do believe I love my own theory more than I do the truth, eh?”

  “Oh, no, no, sir!”

  Again Athor smiled, and this time it was no effort at all. “But I do, you know. I’m as human as anybody else, believe it or not. The Theory of Universal Gravitation brought me every scientific honor this planet has to offer. It’s my passport to immortality, Beenay. You know that. And to have to deal with the possibility that the theory’s wrong—oh, it’s a powerful shock, Beenay, it goes right through me from front to back. Make no mistake about that. —Of course, I still believe that my theory’s correct.”

  “Sir?” said Beenay, all too obviously aghast. “But I’ve checked and checked and checked again, and—”

  “Oh, your findings are correct too, I’m sure of that. For you and Faro and Yimot all to have done it wrong—no, no, I’ve already said I don’t see much chance of that. But what you’ve got here doesn’t necessarily overthrow Universal Gravitation.”

  Beenay blinked a few times. “It doesn’t?”

  “Certainly not,” Athor said, warming to the situation. He felt almost cheerful now. The deathly unreal calm of the first few moments had given way to the very different tranquillity that one feels when one is in pursuit of truth. “What does the Theory of Universal Gravitation say, after all? That every body in the universe exerts a force on all other bodies, proportional to mass and distance. And what did you attempt to do in using Universal Gravitation to compute the orbit of Kalgash? Why, to factor in the gravitational impact that all the various astronomical bodies exert on our world as it travels around Onos. Is that not so?”

  “Yes, sir.”

  “Well, then, there’s no need to throw the Theory of Universal Gravitation out, at least not at this point. What we need to do, my friend, is simply to rethink our comprehension of the universe, and determine whether we’re ignoring something that should be figured into our ca
lculations—some mysterious factor, that is, which all unbeknownst to us is exerting gravitational force on Kalgash and isn’t being taken into account.”

  Beenay’s eyebrows rose alarmingly. He gaped at Athor in what could only have been a look of total astonishment.

  Then he began to laugh. He smothered it at first by clamping his jaws, but the laughter insisted on escaping anyway, causing him to hunch his shoulders and emit strangled lurching coughs; and then he had to clap both his hands over his mouth to hold back the torrent of merriment.

  Athor watched, flabbergasted.

  “An unknown factor!” Beenay blurted, after a moment. “A dragon in the sky! An invisible giant!”

  “Dragons? Giants? What are you talking about, boy?”

  “Yesterday evening—Theremon 762—oh, sir, I’m sorry, I’m really sorry—” Beenay struggled to regain his self-control. Muscles writhed in his face; he blinked violently and caught his breath; he turned away for an instant, and when he turned back he was almost himself again. Shamefacedly he said, “I had a couple of drinks with Theremon 762 yesterday evening—the newspaper columnist, you know—and told him something about what I’d found, and how uneasy I was about bringing my findings to you.”

  “You went to a newspaperman?”

  “A very trustworthy one. A close friend.”

  “They’re all scoundrels, Beenay. Believe me.”

  “Not this one, sir. I know him, and I know he’d never do anything to hurt me or offend me. In fact Theremon gave me some excellent advice, by which I mean he said I absolutely had to come here, which is why I did. But also—trying to offer me some hope, you see, some consolation—he said the same thing you did, that maybe there was an ‘unknown factor’—his exact phrase, an unknown factor—that was confusing our understanding of Kalgash’s orbit. And I laughed and told him that it was useless to drag unknown factors into the situation, that it was too easy a solution. I suggested—sarcastically, of course—that if we allowed any such hypothesis, then we might as well tell ourselves that it was an invisible giant that was pushing Kalgash out of orbit, or the breath of a giant dragon. And now here you are, sir, taking the same line of reasoning—not a layman like Theremon, but the greatest astronomer in the world! —Do you see how foolish I feel, sir?”