Earthlight (Arthur C. Clarke Collection)

by Arthur C. Clarke

  Both Wheeler and Jamieson were surprised that the battle was being fought at such short ranges. There was probably never more than a hundred kilometers between the antagonists, and usually it was much less than this. When one fought with weapons that traveled at the speed of light—indeed, when one fought with light itself—such distances were trivial.

  The explanation did not occur to them until the end of the engagement. All radiation weapons have one limitation: they must obey the law of inverse squares. Only explosive missiles are equally effective from whatever range they have been pro-

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  jected: if one is hit by an atomic bomb, it makes no difference whether it has traveled ten kilometers or a thousand.

  But double the distance of any kind of radiation weapon, and you divide its power by four owing to the spreading of the beam. No wonder, therefore, that the Federal commander was coming as close to his objective as he dared.

  The fort, lacking mobility, had to accept any punishment the ships could give it. After the battle had been on for a few minutes, it was impossible for the unshielded eye to look any­where toward the south. Ever and again the clouds of rock vapor would go sailing up into the sky, falling back on the ground like luminous steam. And presently, as he peered through his darkened goggles and maneuvered his clumsy periscope, Wheeler saw something he could scarcely believe. Around the base of the fortress was a slowly spreading circle of lava, melting down ridges and even small hillocks like lumps of wax.

  That awe-inspiring sight brought home to him, as nothing else had done, the frightful power of the weapons that were being wielded only a few kilometers away. If even the merest stray reflection of those energies reached them here, they would be snuffed out of existence as swiftly as moths in an oxy-hydro-gen flame.

  The three ships appeared to be moving in some complex tactical pattern, so that they could maintain the maximum bom­bardment of the fort while reducing its opportunity of striking back. Several times one of the ships passed vertically overhead, and Wheeler retreated as far into the crack as he could in case any of the radiation scattered from the screens splashed down upon them. Jamieson, who had given up trying to persuade his colleague to take fewer risks, had now crawled some distance along the crevasse, looking for a deeper part, preferably with a good overhang. He was not so far away, however, that the rock was shielding the suit-radios, and Wheeler gave him a con­tinuous commentary on the battle.

  It was hard to believe that the entire engagement had not yet lasted ten minutes. As Wheeler cautiously surveyed the inferno to the south, he noticed that the hemisphere seemed to have lost some of its symmetry. At first he thought that one of the gen­erators might have failed, so that the protective field could no

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  longer be maintained. Then he saw that the lake of lava was at least a kilometer across, and he guessed that the whole fort had floated off its foundations. Probably the defenders were not even aware of the fact. Their insulation must be taking care of solar heats, and would hardly notice the modest warmth of molten rock.

  And now a strange thing was beginning to happen. The rays with which the battle was being fought were no longer quite invisible, for the fortress was no longer in a vacuum. Around it the boiling rock was releasing enormous volumes of gas, through which the paths of the rays were as clearly visible as searchlights in a misty night on Earth. At the same time Wheeler began to notice a continual hail of tiny particles around him. For a moment he was puzzled; then he realized that the rock vapor was condensing after it had been blasted up into the sky. It seemed too light to be dangerous, and he did not mention it to Jamieson—it would only give him something else to worry about. As long as the dust fall was not too heavy, the normal insulation of the suits could deal with it. In any case, it would probably be quite cold by the time it got back to the surface.

  The tenuous and temporary atmosphere round the dome was producing another unexpected effect. Occasional flashes of light­ning darted between ground and sky, draining off the enormous static charges that must be accumulating around the fort. Some of those flashes would have been spectacular by themselves—but they were scarcely visible against the incandescent clouds that generated them.

  Accustomed though he was to the eternal silences of the Moon, Wheeler still felt a sense of unreality at the sight of these tremendous forces striving together without the least whisper of sound. Sometimes a gentle vibration would reach him, per­haps the rock-borne concussion of falling lava. But much of the time, he had the feeling that he was watching a television pro­gram when the sound had failed.

  Afterward, he could hardly believe he had been such a fool as to expose himself to the risks he was running now. At the moment, he felt no fear—only an immense curiosity and ex­citement. He had been caught, though he did not know it, by the deadly glamor of war. There is a fatal strain in men that,

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  whatever reason may say, makes their hearts beat faster when they watch the colors flying and hear the ancient music of the drums.

  Curiously enough, Wheeler did not feel any sense of identi­fication with either side. It seemed to him, in his present ab­normally overwrought mood, that all this was a vast, impersonal display arranged for his special benefit. He felt something ap­proaching contempt for Jamieson, who was missing everything by seeking safety.

  Perhaps the real truth of the matter was that having just escaped from one peril, Wheeler was in the exalted state, akin to drunkenness, in which the idea of personal danger seems absurd. He had managed to get out of the dust bowl—nothing else could harm him now.

  Jamieson had no such consolation. He saw little of the battle, but felt its terror and grandeur far more deeply than his friend. It was too late for regrets, but over and over again he wrestled with his conscience. He felt angry at fate for having placed him in such a position that his action might have decided the destiny of worlds. He was angry, in equal measure, with Earth and the Federation for having let matters come to this. And he was sick at heart as he thought of the future toward which the human race might now be heading.

  Wheeler never knew why the fortress waited so long before it used its main weapon. Perhaps Steffanson—or whoever was in charge—was waiting for the attack to slacken so that he could risk lowering the defenses of the dome for the millisecond that he needed to launch his stiletto.

  Wheeler saw it strike upward, a solid bar of light stabbing at the stars. He remembered the rumors that had gone round the Observatory. So this was what had been seen, flashing above the mountains. He did not have time to reflect on the staggering violation of the laws of optics which this phenomenon implied, for he was staring at the ruined ship above his head. The beam had gone through the Lethe as if she did not exist; the fortress had speared her as an entomologist pierces a butterfly with a pin.

  Whatever one's loyalties, it was a terrible thing to see how the screens of that great ship suddenly vanished as her gen-

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  erators died, leaving her helpless and unprotected in the sky. The secondary weapons of the fort were at her instantly, tearing Out great gashes of metal and boiling away her armor layer by layer. Then, quite slowly, she began to settle toward the Moon, still on an even keel. No one will ever know what stopped her, probably some short-circuit in her controls, since none of her crew could have been left alive. For suddenly she went off to the east in a long, flat trajectory. By that time most of her hull had been boiled away and the skeleton of her framework was almost completely exposed. The crash came, minutes later, as she plunged out of sight beyond the Teneriffe Mountains. A blue-white aurora flickered for a moment below the horizon, and Wheeler waited for the shock to reach him.

  And then, as he stared into the east, he saw a line of dust rising from the plain, sweeping toward him as if driven by a mighty wind. The concussion was racing through the rock, hurl­ing the surface dust high into the sky as it passed. The swift, inexorable approach of that silently moving wall, advancing at the rate o
f several kilometers a second, was enough to strike terror into anyone who did not know its cause. But it was quite harmless; when the wave-front reached him, it was as if a minor earthquake had passed. The veil of dust reduced visibility to Zero for a few seconds, then subsided as swiftly as it had come.

  When Wheeler looked again for the remaining ships, they were so far away that their screens had shrunk to little balls of fire against the zenith. At first he thought they were retreating; then, abruptly, the screens began to expand as they came down into the attack under a terrific vertical acceleration. Over by the fortress the lava, like some tortured living creature, was throw­ing itself madly into the sky as the beams tore into it.

  The Acheron and Eridanus came out of their dives about a kilometer above the fort. For an instant, they were motionless; then they went back into the sky together. But the Eridanus had been mortally wounded, though Wheeler knew only that one of the screens was shrinking much more slowly than the other. With a feeling of helpless fascination, he watched the stricken ship fall back toward the Moon. He wondered if the fort would use its enigmatic weapon again, or whether the de­fenders realized that it was unnecessary.

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  About ten kilometers up, the screens of the Eridmus seemed to explode and she hung unprotected, a blunt torpedo of black metal, almost invisible against the sky. Instantly her light-absorbing paint, and the armor beneath, were torn off by the beams of the fortress. The great ship turned cherry-red, then white. She swung over so that her prow turned toward the Moon, and began her last dive. At first it seemed to Wheeler that she was heading straight toward him; then he saw that she was aimed at the fort. She was obeying her captain's last com­mand.

  It was almost a direct hit. The dying ship smashed into the lake of lava and exploded instantly, engulfing the fortress in an expanding hemisphere of flame. This, thought Wheeler, must surely be the end. He waited for the shock wave to reach him, and again watched the wall of dust sweep by—this time into the north. The concussion was so violent that it jerked him off his feet, and he did not see how anyone in the fort could have survived. Cautiously, he put down the mirror which had given him almost all his view of the battle, and peered over the edge of his trench. He did not know that the final paroxysm was yet to come.

  Incredibly, the dome was still there, though now it seemed that part of it had been sheared away. And it was inert and life­less : its screens were down, its energies exhausted, its garrison, surely, already dead. If so, they had done their work. Of the remaining Federal ship, there was no sign. She was already re­treating toward Mars, her main armament completely useless and her drive units on the point of failure. She would never fight again, yet in the few hours of life that were left to her, she had one more role to play.

  "It's all over, Sid," Wheeler called into his suit radio. "It's safe to come and look now."

  Jamieson climbed up out of a crack fifty meters away, holding the radiation detector in front of him.

  "It's still hot around here," Wheeler heard him grumble, half to himself. "The sooner we get moving the better."

  "Will it be safe to go back to Ferdinand and put through a

  radio" began Wheeler. Then he stopped. Something was

  happening over by the dome.

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  In a blast like an erupting volcano, the ground tore apart. An enormous geyser began to soar into the sky, hurling great boulders thousands of meters toward the stars. It climbed swiftly above the plain, driving a thunderhead of smoke and spray be­fore it. For a moment it towered against the southern sky, like some incredible, heaven-aspiring tree that had sprung from the barren soil of the Moon. Then, almost as swiftly as it had grown, it subsided in silent ruin and its angry vapors dispersed into space.

  The thousands of tons of heavy liquid holding open the deepest shaft that man had ever bored had finally come to the boiling point, as the energies of the battle seeped into the rock. The mine had blown its top as spectacularly as any oil well on Earth, and had proved that an excellent explosion could still be arranged without the aid of atom bombs.

  Chapter XVIII

  To the observatory, the battle was no more than an occasion­al distant earthquake, a faint vibration of the ground which dis­turbed some of the more delicate instruments but did no mate­rial damage. The psychological damage, however, was a differ­ent matter. Nothing is so demoralizing as to know that great and shattering events are taking place, but to be totally unaware of their outcome. The Observatory was full of wild rumors, the Signals Office besieged with inquiries. But even here there was no information. All news broadcasts from Earth had ceased; the whole world was waiting, as if with bated breath, for the fury of the battle to die away so that the victor could be known. That there would be no victor was the one thing that had not been anticipated.

  Not until long after the last vibrations had died away and the radio had announced that the Federation forces were in full retreat did Maclaurin permit anyone to go up to the surface. The report that came down was, after the strain and excitement of the last few hours, not only a relief but a considerable anti­climax. There was a small amount of increased radioactivity

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  about, but not the slightest trace of damage. What it would be like on the other side of the mountains was, of course, a differ­ent matter.

  The news that Wheeler and Jamieson were safe gave a tre­mendous boost to the staff's morale. Owing to a partial break­down of communications, it had taken them almost an hour to contact Earth and to get connected to the Observatory. The delay had been both infuriating and worrying, for it had left them wondering if the Observatory had been destroyed. They dared not set out on foot until they were sure they had somewhere to go—and Ferdinand was now too radioactive to be a safe refuge.

  Sadler was in Communications trying to find out what was happening, when the message came through. Jamieson, sound­ing very tired, gave a brief report of the battle and asked for instructions.

  "What's the radiation reading inside the cab?" Maclaurin asked. Jamieson called back the figures: it still seemed strange to Sadler that the message should have to go all the way to Earth just to span a hundred kilometers of the Moon, and he was never able to get used to the three-second delay that this implied.

  "I'll get the health section to work out the tolerance," Mac­laurin answered. "You say it's only a quarter of that reading out in the open?"

  "Yes—we've stayed outside the tractor as much as possible, and have come in every ten minutes to try and contact you."

  "The best plan is this—we'll send a Caterpillar right away, and you start walking toward us. Any particular rendezvous you'd like to aim for?"

  Jamieson thought for a moment.

  "Tell your driver to head for the five-kilometer marker on this side of Prospect; we'll reach it about the same time as he does. We'll keep our suit radios on so there'll be no chance of him missing us."

  As Maclaurin was giving his orders, Sadler asked if there was room for an extra passenger in the rescue tractor. It would give him a chance of questioning Wheeler and Jamieson much sooner than would otherwise be the case. When they reached the Ob­servatory—though they did not know it yet—they would be whipped into hospital at once and treated for radiation sickness.

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  They were in no serious danger, but Sadler doubted that he would have much chance of seeing them for a while when the doctors got hold of them.

  Maclaurin granted the request, adding the comment: "Of course, you realize this means that you'll have to tell them who you are. Then the whole Observatory will know inside ten min­utes."

  "I've thought of that," Sadler replied. "It doesn't matter now." Always assuming, he added to himself, that it ever did.

  Half an hour later, he was learning the difference between travel in the smooth, swift monorail and in a jolting tractor. After a while he became used to the nightmare grades the driver was light-heartedly attacking, and ceased to regret volunteering for this mi
ssion. Besides the operating crew, the vehicle was carrying the chief medical officer, who hoped to make blood counts and give injections as soon as the rescue had been ef­fected.

  There was no dramatic climax to the expedition; as soon as they topped Prospect Pass, they made radio contact with the two men trudging toward them. Fifteen minutes later the mov­ing figures appeared on the skyline, and there was no ceremony apart from fervent handshakes as they came aboard the tractor.

  They halted for a while so that the M.O. could give his in­jections and make his tests. When he had finished he told Wheeler: "You're going to be in bed for the next week, but there's no need to worry."

  "What about me?" asked Jamieson.