Isaac Asimov - Nightfall (novel)

“You haven’t finished the one you’ve got,” Sheerin reminded the young astronomer.

“Well, what of it? It still calls for another one afterward. Waiter! Waiter!”

Athor 77 felt fatigue sweeping through him in shimmering waves. The Observatory director had lost all track of time. Had he really been at his desk sixteen straight hours? And yesterday the same. And the day before—

That was what Nyilda claimed, anyway. He had spoken to her just a little while before. His wife’s face on the screen had been tense, drawn, unmistakably worried.

“Won’t you come home for a rest, Athor? You’ve been going at it practically around the clock.”

“Have I?”

“You aren’t a young man, you know.”

“I’m not a senile one, either, Nyilda. And this is exhilarating work. After a decade of initialing budget reports and reading other people’s research papers I’m finally doing some real work again. I love it.”

She looked even more troubled. “But you don’t need to be doing research at your age. Your reputation is secure, Athor!”

“Ah, is it?”

“Your name will be famous in the history of astronomy forever.”

“Or infamous,” he said balefully.

“Athor, I don’t understand what you—”

“Let me be, Nyilda. I’m not going to keel over at my desk, believe me. I feel rejuvenated by what I’m doing here. And it’s work that only I can do. If that sounds pigheaded, so be it, but it’s absolutely essential that I—”

She sighed. “Yes, of course. But don’t overdo it, Athor. That’s all I ask.”

Was he overdoing it? he wondered now. Yes, yes, of course he was. There wasn’t any other way. You couldn’t dabble in these matters. You had to throw yourself wholeheartedly into them. When he was working out Universal Gravitation he had worked sixteen-, eighteen-, twenty-hour days for weeks on end, sleeping only when sleep became unavoidable, snatching brief naps and awakening ready and eager for work, with his mind still bubbling with the equations he had left unfinished a little while before.

But he had been only thirty-five or so, then. He was nearly seventy now. There was no denying the inroads of age. His head ached, his throat was dry, there was a nasty pounding in his chest. Despite the warmth of his office his fingertips were chilly with weariness. His knees were throbbing. Every part of his body protested the strain he had been putting on it.

Just a little while longer today, he promised himself, and then I’ll go home.

Just a little while longer.

Postulate Eight —

“Sir?”

“What is it?” he asked.

But his voice must have turned the question into some sort of fierce snarl, for when he glanced around he saw young Yimot standing in the doorway doing a bizarre series of wild twitches and convulsions, as though he were dancing on hot embers. There was terror in the boy’s eyes. Of course Yimot always seemed intimidated by the Observatory director—everybody around here was, not just graduate students, and Athor was used to it. Athor was awesome and he knew it. But this went beyond the ordinary. Yimot was gazing at him in undisguised fear mingled with what seemed like astonishment.

Yimot struggled visibly to find his voice and said huskily, “The calculations you wanted, sir—”

“Oh. Yes. Yes. Here, give me.”

Athor’s hand was trembling violently as he reached for the printouts Yimot had brought him. Both of them stared at it, aghast. The long bony fingers were pale as death and they were quivering with a vehemence that not even Yimot, famed for his remarkable nervous reactions, could have equaled. Athor willed his hand to be still, but it would not. He might just as well have been willing Onos to spin backward across the sky.

With an effort he snatched the papers from Yimot and slapped them down on the desk.

Yimot said, “If there’s anything I can get you, sir—”

“Medication, you mean? How dare you suggest—”

“I just meant something to eat, or maybe a cold drink,” Yimot said in a barely audible whisper. He backed slowly away as if expecting Athor to growl and leap for his throat.

“Ah. Ah. I see. No, I’m fine, Yimot. Fine!”

“Yes, sir.”

The student went out. Athor closed his eyes a moment, took three or four deep breaths, struggled to calm himself. He was near the end of his task, of that he was sure. These figures that he had asked Yimot to work out for him were almost certainly the last confirmation he needed. But the question now was whether the work was going to finish him before he finished the work.

He looked at Yimot’s numbers.

Three screens sat before him on his desk. On the left-hand one was the orbit of Kalgash as calculated according to conventional reckoning under the Theory of Universal Gravitation, outlined in blazing red. On the right-hand screen, in fiery yellow, was the revised orbit that Beenay had produced, using the new university computer and the most recent observations of Kalgash’s actual position. The middle screen carried both orbits plotted one over the other. In the past five days Athor had produced seven different postulates to account for the deviation between the theoretical orbit and the observed one, and he could call up any of those seven postulates on the middle screen with a single key-stroke.

The trouble was that all seven of them were nonsense, and he knew it. Each one had a fatal flaw at its heart—an assumption that was there not because the calculations justified it, but only because the situation called for some such sort of special assumption in order to make the numbers turn out the right way. Nothing was provable, nothing was confirmable. It was as though in each case he had simply decreed, at some point in the chain of logic, that a fairy godmother would step in and adjust the gravitational interactions to account for the deviation. In truth that was precisely what Athor knew he needed to find. But it had to be a real fairy godmother.

Postulate Eight, now—

He began keying in Yimot’s calculations. Several times his trembling fingers betrayed him and he made an error; but his mind was still sharp enough to tell him instantly that he had hit the wrong key, and he backed up and repaired the damage each time. Twice, as he worked, he nearly blacked out from the intensity of his effort. But he forced himself to go on.

You are the only person in the world who can possibly do this , he told himself as he worked. And so you must.

It sounded foolish to him, and madly egocentric, and perhaps a little insane. It probably wasn’t even true. But at this stage in his exhaustion he couldn’t allow himself to consider any other premise but that of his own indispensability. All the basic concepts of this project were held in his mind, and his mind alone. He had to push himself onward until he had closed the last link in the chain. Until—

There.

The last of Yimot’s numbers went into the computer.

Athor hit the key that brought the two orbits up into view simultaneously on the middle screen, and hit the key that integrated the new number with the existing patterns.

The brilliant red ellipse that was the original theoretical orbit wavered and shifted, and suddenly it was gone. So was the yellow one of the observed orbit. Now there was only a single line on the screen, a deep, intense orange, the two orbital simulations overlapping to the last decimal place.

Athor gasped. For a long moment he studied the screen, and then he closed his eyes again and bowed his head against the edge of the desk. The orange ellipse blazed like a ring of flame against his closed eyelids.

He felt a curious sense of exultation mixed with dismay.