by Hal Clement
Arthur entered after about fifteen minutes, carrying three packs under his arms. Two of these he tossed to his brother and the doctor, remarking, “Pillows in one suite, anyway!” The other he retained. The three men rolled up the packs and placed them under the canvas at the heads of their sleeping bags, conscious meanwhile of the never-ending scrutiny from the door; then they leaned back against the wall and relaxed.
The twins had tobacco, and all three smoked as they talked. A remark of Leo’s, which opened the conversation, eased Little’s mind of one problem which had been bothering him.
“Before we do or say anything else, Doc,” said the navigator, “please think carefully before you tell us anything. I suppose you found out a good deal from the Vegans, and I wouldn’t be surprised to know you have a campaign all mapped out; but I don’t want to know more than necessary. I have developed, from what the Vegans said and from what I’ve seen myself, a very healthy respect for the intuition, or guessing powers, or whatever it is, of our silent watchers. It makes me uncomfortable. And the less I know the more natural I can let myself act. All right?”
“All right; that was my own idea, too,” answered the doctor. “I will tell you no more than necessary. In the first place I should, like Magill, like to know our location on this planet and the planet’s location in space. That, unquestionably, is your job, Leo. Then I want to get the information to the handiest Union base or ship. That’s all. I don’t believe we could break out of here, though probably Keys will try. I pin my hope on our broadcasting a message from inside and letting people already outside do the rest.”
The brothers nodded. “That’s clear enough,” said Leo, “and I can probably locate us fairly well if . . . Art, did you say you had a grating in that kit of yours?”
“Yes,” was the answer. “Do you need it?”
“Uncertain, but probably. I’ll have to identify the local navigation beacon somehow, and its spectrum will be the most outstanding hallmark. Why don’t Doc and I go outside now and do some star-gazing, while you curl up in your sleeping bag and see if the shadows don’t follow us? If they do, you can rummage in the kit without being seen, and come out in a few minutes with the grating and a couple of the lenses you mentioned. If they don’t, we’ll do what we can with the naked eye and come back. Sound?”
“Solid. Be seeing you.”
Arthur extinguished the stub of his cigarette, loosened his belt and shirt, and began removing his boots, while Leo and Little rose and went out into the hallway. Pentapods, scattered along the corridor, eyed them as they emerged, but made no move to intercept them. The door opening outside had been left ajar by the Earthmen in their policy of avoiding the use of the building’s ventilation system, and the guards were evidently following a policy of noninterference with regard to everything but weapons. The panel was still partly open.
Little pushed it wide, and the two human beings went out onto the roof. To their surprise they were not followed; but both realized that there might already be guards on the roof. They moved out of the path of the light from the door and approached the nearest wall.
The mountains to the northeast were silhouetted against the almost equally dark sky; the forest at their feet was indistinguishable. No glow or spark of light suggested the presence, anywhere in the scene, of the men who had escaped nine hours before, though Little and Dennis strained their eyes looking. Not even a reflection from the river the doctor believed must be present broke the dark expanse.
The sky offered more material for comment. The Galaxy was lower in the west and the moon higher. Dennis, looking at the latter, did some rapid mental arithmetic. It had risen about an hour and a half ago, and would probably reach the zenith in a little more than another hour. Its sidereal period, then, must be about eight hours, and its distance, if this world had the same size and mass as Earth, a little over eight thousand miles from the surface. It was now nearly at “first quarter,” but its dark side was faintly visible, presumably illuminated by the reflected light of the planet. Somewhat less than four hours after sunset, the satellite should enter the planet’s shadow and be eclipsed for about forty minutes, unless its orbit were more highly inclined to that of the planet than appeared to be the case.
Little was looking at the stars, spread over the sky in unfamiliar constellations. “Which of these is the local navigation beacon, and how do you identify it?” he asked. “And why do you pick out one star to call a beacon?”
“It would be possible to obtain our position from any three stars whose location is on the charts,” answered Dennis, “but it is much easier, as a rule, to use certain individuals, because tables have been computed for use with them, and they are easier to identify. I don’t have the tables with me, of course, but the beacon for this neighborhood and the Galaxy, together, would give me a fairly good idea. We use the brightest available stars for beacons, naturally—Rigel and Deneb in the Solar sector, for example. For navigation in the Larger Cloud we use a slightly different system, which employs two super-giant stars back in the Galaxy and the one local beacon which covers the whole Cloud—S Doradus. It shouldn’t be hard to find, even without instruments, since it’s a first-magnitude star at a thousand parsecs; but we always like to check the spectrum, if possible. Most beacon stars, of course, are O, B, or A supergiants, but there are usually detectable individual differences which can be picked out by a good instrument. We haven’t a good instrument, but fortunately S Doradus has a very distinctive spectrum.”
Little nodded. “I can see that much. Don’t tell me how you reduce the observations to get your position; it would certainly go beyond my mathematical limit, and I don’t like to be shown up.”
“It’s not difficult—elementary spherical trig. If you know what a direction cosine is, you’re all right. Matter of fact, that’s how positions are indicated—three direction cosines from a given beacon, plus distance. I don’t know how we’ll get the distance—I can estimate brightness to a tenth of a magnitude, but that may answer to a small percentage of an awful distance. We usually can triangulate, but not in the Cloud.”
“I’ll take your word for it,” replied the doctor. “Can you see anything that might be your beacon?”
“There’s a fairly bright specimen sitting just above the north horizon, that seems to have a tinge of yellow; and there’s another right overhead. If Art ever gets here with the lenses and grating I’ll test them. I suppose he can’t make it, since the dumb chums didn’t follow us out here and give him a chance to burrow into the kit.”
“He may find a way to do it anyway,” remarked the doctor.
“It would be just like him to try, and lose the kit,” was the pessimistic answer.
Even Little was growing discouraged by the time Arthur finally arrived. They had been out nearly an hour, Little amusing himself by strolling along the walls to see whether anything were visible below, and Leo observing the satellite as it approached the zenith. He had already come to the conclusion, from the fact that the sun had set practically “straight down,” that they were near the equator of the planet. It now seemed that the moon was in the equatorial plane, since it was rising to a point directly overhead. It was well past first quarter now, but the unlighted crescent was still visible. Leo had just noticed this fact when Arthur’s voice interrupted his pondering.
“I assumed you wanted the lenses for a telescope of sorts, and chose accordingly,” said the technician. “It took me a long time to work the kit out of the pack and into the sleeping bag because the guards were looking in every two or three minutes. I don’t know what will happen when they find me gone.”
“I do, you chump,” answered Leo. “Two or three of them will drift out here after us, and some more will seize the chance to investigate the pack whose position you changed so often.”
“Think so?” asked Arthur. “Here are the lenses and grating. I brought the rod and lens clamps, too, but I’m afraid you’ll have to get along without a tube.” His brother accepted the asso
rtment and fell to work. The doctor looked on silently. Arthur had brought a light also, and held it on the step which served as a workbench.
Leo, after a moment’s thought, discarded one lens and used the other—the one of longer focal length. He clamped this at one end of the rod, with the plane side toward the center. The grating was smaller than the lens, and he clamped it against the plane face of the latter with the excess glass blocked off with paper. Another sheet of paper—a leaf torn from his sketch pad—was clamped to the rod at the focal distance of the lens, completing the crude spectroscope.
He set the instrument on the wall, propping it so that it was pointed toward the northern horizon and one of the stars he had mentioned. He leaned over it, to cut off the moonlight. The other two also leaned forward to see the results.
A little streak of color, narrow as a pencil line, was just visible on the paper screen. Leo brought his eyes as close as he could, striving to perceive the tiny dark gaps that should have existed; but the resolution of the instrument was not sufficient. After a moment’s pause, he returned to the original idea, removing the paper and clamping the other lens in normal eyepiece position. This proved successful. He could make out enough to identify both the stars he had counted on as unquestionably sun-type G stars, probably no more than a few parsecs distant, and definitely not the giant he sought.
The navigator began to wear a worried expression. There were several thousand stars visible to the naked eye, and only a few of them were obviously not the object of his search. After a few minutes, however, he began a methodical examination of all the brighter yellow and white stars, one after another. Arthur and the doctor saw that interruption would not be helpful, so they withdrew a few yards and conversed in low tones.
“What will you do if Leo does get our position?” asked the technician. “I suppose you have some idea.”
“The idea I have depends almost entirely on you,” answered Little. “I have been told that a second-order transmitter is less complicated than an ordinary radio. Could you build one?”
Dennis frowned and hesitated. “If I had all the materials and no interruptions, yes. Here and now, I don’t know if the necessary equipment is available, and I’m reasonably sure we wouldn’t be allowed to do it, anyway.”
“You said there were two atomic tools in your kit, a heater and a stroboscope,” said Little. “Would their parts be enough?” Once again Dennis paused to think.
“The welder wouldn’t—it’s just a converter and a tungsten element. The stroboscope converts with a direct electron current and a variable oscillator and—I believe it could be done. But it wouldn’t handle much power, and the range would be nothing to speak of.”
“That doesn’t matter, as I see it. All I want to know is that you can build a vision transmitter with the material on hand—”
“Wait a minute!” interrupted Arthur. “I didn’t say a vision unit. What do you need that for? All I was counting on was voice transmission. That won’t be very difficult.”
Little shook his head. “Vision or nothing. I don’t want to tell you why, for the reason Leo gave. But please, if you don’t want me to have to redesign the whole plan, find a way to construct a vision transmitter. And I hate to be too exacting, but I’d like it done before that ship leaves again. I don’t know how long they usually stay here, but I notice they’re stocking up.”
“Sure,” groaned Dennis. “Right away. Doc, if it were anyone else I’d know he was crazy, but with you it’s only a strong suspicion. I’ll try—but Lord knows where I can come by an icon tube.”
Little grinned invisibly in the darkness. “The Vegans said they smuggled up a complete neutrino assembly. It was taken away from them later, but it gives you an idea of what can be done.”
“They didn’t give you an idea of their technique, I suppose? I’m not too proud to learn.”
“I didn’t ask them. There were guards around. Good luck!”
Little went back to Leo, who was resting his arms. Not a single O-class spectrum had yet been picked up by the instrument.
“If I were sure it were there, I wouldn’t mind so much,” he said, wiping his forehead. “But it’s just as likely to be in the daylight half of the sky. I’d rather not have to wait here half of whatever time it takes this world to amble around its sun, just to get a rough idea of where I am.”
Little nodded sympathetically—after all, he was the one who wanted their location. “Does the moonlight interfere any?” he asked.
“It did, until I made a rough tube out of paper. It’s a little hard to hold together. But speaking of the moon, Doc, have you noticed anything strange about it?”
“I wouldn’t,” answered Little. “Is something wrong? It looks natural to me.
“It doesn’t to me. It did right after sunset, when it was a narrow crescent. We could see the rest of it then, but reflection from this planet could have accounted for that. But it doesn’t now! The darn thing’s nearly full, and you can still see the strip that the sun doesn’t reach. This world can’t possibly reflect enough light for that. What’s lighting it up?”
“I’m afraid it’s no use to ask me,” said the doctor. “I can guarantee it’s not radioactivity, because that much radioactive matter so close would have prevented the existence of life on this world. It would have been burned sterile; we’d probably be dead now ourselves. I don’t know any astronomy, but I can tell you all you want to know about gamma-ray burns.”
“That occurred to me, too,” agreed Leo. “It seems that there must be something, at present invisible to us, shining on that satellite. I think in a few minutes we’ll be able to get an idea of where it’s shining from, too.”
“How?” asked Little and Arthur with one voice.
“The moon should pass into this planet’s shadow very shortly,” answered Leo. “A lunar eclipse. The satellite must have one every revolution—almost four times a day, I should say. The sun’s light will be cut off, except for the fraction scattered by the atmosphere of this world, and we should be able to tell from the shape of the part illuminated by this mystery source, the direction of the source. We’ll wait.” The other two nodded. Even Little, who was no astronomer, understood the mechanism of an eclipse. The three settled themselves on the broad steps inside the wall.
They had not long to wait. It was about three and a quarter hours after sunset, and the first outlying tentacles of the looming Galaxy were just dipping below the western horizon, when Leo marked the first darkening of the eastern limb of the nearly full moon. It was not like the protracted lunar eclipse of Earth; the satellite was moving far more swiftly, and took less than a minute to travel its own diameter. There was a feeble, preliminary reddening as it plunged into the region illuminated only by air-scattered light; then this was gone, as the little body passed on into the umbra of the planet’s shadow.
It should have disappeared. No possible reflection from the planet it circled could have given it a touch of illumination, for it looked down only on the night side of the world. Yet part of it was still to be seen—a ghostly, dim-lit crescent, a little less than half full, its convex side facing east. There was no possible question of the nature of the light source. Leo estimated the distance of the moon above the eastern horizon, and the angular breadth of illuminated surface; there was only a small difference.
“It will rise before long,” he said. “I’m staying to see. You fellows can go back to sleep if you wish; we’ve been out over two hours and we’ll need some sleep.”
“We’ll stay,” said Little. “This gets interesting. Do you think there’s another, very bright moon? Large enough, perhaps, to be habitable?”
Leo shook his head. “I don’t believe any possible moon could do that,” he said. Arthur nodded in silent agreement, and for many minutes the three sat without speaking as the dimly lit crescent dipped lower toward the eastern horizon. Leo had judged roughly that the eclipse should last about forty minutes.
It had not ended when Arthur po
inted silently to the east. A spur of the mountain range whose principal peaks lay to the northeast had become a little clearer, silhouetted against a suddenly brighter patch of sky. The brilliance grew and spread, paling the stars in that quarter of the heavens as though dawn were breaking; and quite suddenly the source rode clear of the concealing hill and presented itself to view. The undulations of the landscape were abruptly visible, standing out against the long shadows cast by the light of the newcomer, which hung, far brighter than the moon at its best, just above the peaks.
The men looked on in awe. They had seen the mad splendor of the spiraling gas streams hurled forth from binaries like Beta Lyrae; they had driven through the hearts of globular clusters, with giant suns by the myriad on every hand; but somehow the lonely, majestic grandeur of this object was more impressive. A star—too distant to show a perceptible disk—too bright to be gazed at directly, putting to shame the surrounding celestial objects. Even the moon, sliding out of the shadow in an apologetic fashion, no longer seemed bright.
Arthur Dennis was the first to speak. “It gets you, doesn’t it? I suppose it’s a companion to the sun, or else—”
“Or else” said Leo flatly, snatching the spectroscope. The great star was white, with just a suspicion of topaz in its glow, and Leo was prone to jump to conclusions. One glance through the instrument, sweeping it slightly from left to right, was enough. He grinned, removed the eye lens, and replaced the paper screen of the original arrangement, and three heads bent once more to look at the streak of color.
It wasn’t a streak this time. A single bright point centered itself directly behind the objective lens, and to either side of this there extended a broken series of dashes—the intense emission bands, bordered on the violet side by relatively sharp dark lines, which characterize what the early astronomers called a “P Cygni” star. The continuous background spectrum was too faint to show; the grating was so coarse that several orders of the spectrum fell on the paper at once.