Colonial Survey

by Murray Leinster

  So Bordman computed carefully. It was ironic that he had to go to such trouble simply because he didn’t have test-rockets like the Survey uses to get a picture of a planet’s weather-pattern. They rise vertically for fifty miles or so, trailing a thread of sodium vapor behind them. The trail is detectable for some time, and ground instruments record each displacement by winds blowing in different directions at different speeds, one over the other. Such a rocket with its loading slightly changed would do all Bordman had in mind. But he didn’t have one, so something much more elaborate was called for.

  A landing-grid has to be not less than half a mile across and two thousand feet high because its field has to reach out five planetary diameters to handle ships that land and take off. To handle solid objects it has to be accurate, though power can be drawn with an improvisation. To thrust a sodium vapor bomb anywhere from twenty to fifty miles high, he’d need a grid only six feet wide and five high. It could throw much higher, of course, and hold what it threw. But doubling the size would make accuracy easier.

  He tripled the dimensions. There would be a grid eighteen feet across and fifteen high. Tuned to the casing of a small bomb, it could hold it steady at seven hundred fifty thousand feet, far beyond necessity. He began to make the detail drawings.

  Herndon came back with half a dozen chosen colonists. They were young men, technicians rather than scientists. Some of them were several years younger than Bordman. There were grim and stunned expressions on some faces, but one tried to pretend nonchalance, and two seemed trying to suppress fury at the monstrous occurrence that would destroy not only their own lives, but everything they remembered on the planet which was their home. They looked almost challengingly at Bordman.

  He explained. He was going to put a cloud of metallic vapor up in the ionosphere. Sodium if he had to, potassium if he could, zinc if he must. Those metals were readily ionized by sunlight, much more readily than atmospheric gases. In effect, he was going to supply a certain area of the ionosphere with material to increase the efficiency of sunshine in providing electric power. As a side-line, there would be increased conductivity from the normal ionosphere.

  “Something like this was done centuries ago, back on Earth,” he explained. “They used rockets, and made sodium-vapor clouds as much as twenty and thirty miles long. Even nowadays the Survey uses test rockets with trails of sodium vapor. It will work to some degree. We’ll find out how much.”

  He felt Herndon’s eyes upon him. They were almost dazedly respectful. But one of the technicians said:

  “How long will those clouds last?”

  “That high, three or four days,” Bordman told him. “They won’t help much at night, but they should step up power-intake while the sun shines on them.”

  A man in the back said, “Hup!” The significance was, “Let’s go!”

  Somebody else said feverishly, “What do we do? Got working drawings? Who makes the bombs? Who does what? Let’s get at this!”

  Then there was confusion, and Herndon vanished. Bordman suspected he’d gone to have Riki put this theory into dot-and-dash code for beam-transmission back to Lani II. But there was no time to stop him. These men wanted precise information and it was half an hour before the last of them had gone out with free-hand sketches, and had come back for further explanation of a doubtful point, and other men had come in to demand a share in the job.

  When he was alone again, Bordman thought, Maybe it’s worth doing because it’ll get Riki on the Survey ship. But they think it means saving the people back home!

  Which it didn’t. Taking energy out of sunlight is taking energy out of sunlight, no matter how you do it. Take it out as electric power, and there’s less heat left. Warm one place with electric power, and everywhere else is a little colder. There’s an equation. On this colony-world it wouldn’t matter, but on the home world it would. The more there was trickery to gather heat, the more heat would be needed…Again it might postpone the death of twenty million people, but it would never, never prevent it…

  The door slid aside and Riki came in. She stammered a little.

  “I just coded what Ken told me to send back home. It will—it will do everything! It’s wonderful! I wanted to tell you!”

  “Consider,” Bordman said, in a desperate attempt to take it lightly, “that I’ve taken a bow.”

  He tried to smile. It was not a success. And Riki suddenly drew a deep breath and looked at him in a new fashion.

  “Ken’s right,” she said softly. “He says you can’t get conceited. You’re not satisfied with yourself even now, are you?” She smiled. “But what I like is that you aren’t really smart. A woman can make you do things. I have!”

  He looked at her uneasily. She grinned.

  “I, even I, can at least pretend to myself that I helped bring this about! If I hadn’t said please change the facts that are so annoying, and if I hadn’t said you were big and strong and clever…I’m going to tell myself for the rest of my life that I helped make you do it!”

  Bordman swallowed.

  “I’m afraid,” he said, “that it won’t work again.”

  She cocked her head on one side.

  “No?”

  He stared at her apprehensively. And then with a bewildering change of emotional reaction, he saw that her eyes were filled with tears. She stamped her foot.

  “You’re horrible!” she cried. “Here I came in, and—and if you think you can get me kidnaped to safety without even telling me that you ‘rather like’ me, as you told my brother, or that I’m ‘pretty wonderful—’”

  He was stunned, that she knew. She stamped her foot again.

  “For Heaven’s sake!” she wailed. “Do I have to ask you to kiss me?”

  During the last night of preparation, Bordman sat by a thermometer registering the outside temperature. He hovered over it as one might over a sick child. He watched it and sweated, though the inside temperature of the drone-hull was lowered to save power. There was nothing he could actually do. At midnight the thermometer said it was seventy degrees below zero Fahrenheit. At half-way to dawn it was eighty degrees below zero Fahrenheit. The hour before dawn it was eighty-five degrees below zero. Then he sweated profusely. The meaning of the slowed descent was that carbon dioxide was being frozen out of the upper layers of the atmosphere. The frozen particles were drifting slowly downward, and as they reached lower and faintly warmer levels they returned to the state of gas. But there was a level, above the CO2, where the temperature was plummeting.

  The height to which carbon dioxide existed was dropping. Slowly, but inexorably. And above the carbon-dioxide level there was no bottom limit to the temperature. The greenhouse effect was due to CO2. Where it wasn’t, the cold of space moved down. If at ground-level the thermometer read ever-so-slightly less than one hundred nine below zero, then everything was finished. Without the greenhouse effect, the night-side of the planet would lose its remaining heat with a rush. Even the day side, once cold enough, would lose heat to emptiness as fast as it came from the sun. Minus one hundred nine point three was the critical reading. If it went down to that it would plunge to a hundred and fifty or two hundred degrees below zero, or more. And it would never come up again.

  There would be rain at nightfall, a rain of oxygen frozen to a liquid and splashing on the ground. Human life would be impossible, in any shelter and under any conditions. Even space-suits would not protect against an atmosphere sucking heat from it at that rate. A space-suit can be heated against the loss of temperature due to radiation in a vacuum. It could not be heated against nitrogen which would chill it irresistibly by contact.

  But, as Bordman sweated over it, the thermometer steadied at minus eighty-five degrees. When the dawn came, it rose to seventy. By mid-morning, the temperature in bright sunshine was no lower than sixty-five degrees below zero.

  But there was no bounce left in Bordman when Herndon came for him.

  “Your phone-plate’s been flashing,” said Herndon, “and
you didn’t answer. Must have had your back to it. Riki’s over in the mine, watching them get things ready. She was worried that she couldn’t call you. Asked me to find out what was the trouble.”

  “Has she got something to heat the air she breathes?” asked Bordman.

  “Naturally,” said Herndon. He added curiously, “What’s the matter?”

  “We almost took our licking,” Bordman told him. “I’m afraid for tonight, and tomorrow night too. If the CO2 freezes—”

  “We’ll have power!” Herndon insisted. “We’ll build ice-tunnels and ice-domes. We’ll build a city under ice, if we have to. But we’ll have power!”

  “I doubt it very much,” said Bordman. “I wish you hadn’t told Riki of the bargain to get her away from here when the Survey ship comes!”

  Herndon grinned.

  “Is the little grid ready?” asked Bordman.

  “Everything’s set,” said Herndon. “It’s in the mine-tunnel with radiant heaters playing on it. The bombs are ready. We made enough to last for months, while we were at it. No use taking chances!”

  Bordman looked at him queerly. Then he said:

  “We might as well go out and try the thing, then.”

  He put on the cold-garments as they were now modified for the increased frigidity. Nobody could breathe air at minus sixty-five degrees without getting his lungs frost-bitten. So there was now a plastic mask to cover one’s face, and the air one breathed outdoors was heated as it came through a wire-gauze snout. But still it was not wise to stay out of shelter for too long a time.

  Bordman and Herndon went out-of-doors. They stepped out of the cold-lock and gazed about them. The sun seemed markedly paler, and now it had lost its sundogs again. Ice-crystals no longer floated in the almost congealed air. The sky was dark. It was almost purple, and it seemed to Bordman that he could detect faint flecks of light in it. They would be stars, shining in the daytime.

  There seemed no one about at all, only the white coldness of the mountains. But there was a movement at the mine-drift, and something came out of it. Four men appeared, muffled up like Bordman himself. They rolled the eighteen-foot grid out of the mine-mouth, moving it on those inflated bags which are so much better than rollers for rough terrain. They looked absurdly like bears with steaming noses in their masks and clothing. They had some sort of powered pusher with them, and they got the metal cage to the very top of a rounded stone upcrop which rose in the center of the valley.

  “We picked that spot,” said Herndon’s muffled voice through the chill, “because by shifting the grid’s position it can be aimed, and be on a solid base. Right?”

  “Quite all right,” said Bordman. “We’ll go work it.”

  The two men walked across the valley, in which nothing moved except the padded figures of the four technicians. Their wire-gauze breathing-masks seemed to emit smoke. They waved to Bordman in greeting.

  I’m popular again, he thought drearily, but it doesn’t matter. Getting the Survey ship to ground won’t help now, since Riki’s forewarned. And this trick won’t solve anything permanently on the home planet. It’ll just postpone things.

  Even when Riki, muffled like the rest, waved to him from the mouth of the tunnel, his spirits did not lift. The thing he wanted was to look forward to years and years of being with Riki. He wanted, in fact, to look forward to forever. And there might not be a tomorrow.

  “I had the control-board rolled out here,” she called through her mask. “It’s cold, but you can watch!”

  It wouldn’t be much to watch. If everything went all right, some dial-needles would kick over violently, and their readings would go up and up. But they wouldn’t be readings of temperature. Presently the big grid would report increased power from the sky. But tonight the temperature would drop a little farther. Tomorrow night it would drop further still. When it reached one hundred nine point three degrees below zero at ground-level, that would be the finish.

  Another of the figures that looked like a bear now went out of the mine-mouth, trudging toward the grid. It carried a muffled, well-wrapped object in its arms. It stooped and crept between the spokes of the grid, and put the object on the stone. Bordman traced cables with his eyes, from the grid to the control-board, and from the board back to the reserve-power storage cells, deep in the mountain.

  “The grid’s tuned to the bomb,” said Riki, close beside him. “I checked that myself!”

  The bear-like figure out in the valley jerked at the bomb. There was a small rising cloud of grayish vapor. It continued. The figure climbed hastily out of the grid. When the man was clear, Bordman threw a switch.

  There was a thin whining sound, and the wrapped, smoking object leaped upward. It seemed to fall toward the sky. There was no more of drama than that. An object the size of a basketball fell upward, swiftly, until it disappeared.

  Bordman sat quite still, watching the control-board dials. Presently he corrected this, and shifted that. He did not want the bomb to have too high an upward velocity. At a hundred thousand feet it would find very little air to stop the rise of the vapor it was to release.

  The field-focus dial reached its indication of one hundred thousand feet. Bordman reversed the lift-switch. He counted, and then switched the power off. The small, thin whine ended.

  He threw the power-intake switch. The power-yield needle stirred. The minute grid was drawing power like its vaster counterpart, but its field was infinitesimal by comparison. It drew power as a soda-straw might draw water from wet sand.

  Then the intake-needle kicked. It swung sharply, and wavered, and then began a steady, even, climbing movement across the markings on the dial-face. Riki was not watching that.

  “They see something!” she panted. “Look at them!”

  The four men who had trundled the smaller grid to its place, now stared upward. They flung out their arms. One of them jumped up and down. They leaped. They practically danced.

  “Let’s go see,” said Bordman.

  He went out of the tunnel with Riki. They gazed upward. And directly overhead, where the sky was darkest blue and where it had seemed that stars shone through the daylight, there was a minute cloud. But it grew. Its edges were yellow, saffron-yellow. It expanded and spread. Presently it began to thin. As it thinned, it began to shine. It was luminous. And the luminosity had a strange, familiar quality.

  Somebody came panting down the tunnel, from inside the mountain.

  “The grid—” he panted. “The big grid! It’s pumping power! Big power! BIG power!”

  But Bordman was looking at the sky, as if he did not quite believe his eyes. The cloud now expanded very slowly, but still it grew. And it was not regular in shape. The bomb had not shattered quite evenly, and the vapor had poured out more on one side than the other. There was a narrow, arching arm of brightness…

  “It looks,” said Riki breathlessly, “like a comet!”

  And then Bordman froze in every muscle. He stared at the cloud he had made aloft, and his hands clenched in their mittens, and he swallowed behind his cold-mask.

  “Th-that’s it,” he said in a hushed voice. “It’s—very much like a comet. I’m glad you said that! We can make something even more like a comet. We can use all the bombs we’ve made, right away, to make it. And we’ve got to hurry so it won’t get any colder tonight!”

  Which, of course, sounded like insanity. Riki looked apprehensively at him. But Bordman had just thought of something. And nobody had taught it to him and he hadn’t gotten it out of books. But he’d seen a comet.

  The new idea was so promising that he regarded it with anguished unease for fear it would not hold up. It was an idea that really ought to change the facts resulting naturally from a lowered solar constant in a sol-type star.

  Half the colony set to work to make more bombs when the effect of the first bomb showed up. The men were not very efficient, at first, because they tended to want to stop work and dance from time to time. But they worked with an impassioned enthu
siasm. They made more bomb-casings, and they prepared more sodium and potassium metal and more fuses, and more insulation to wrap around the bombs to protect them from the cold of airless space.

  Because these were to go out to airlessness. The miniature grid could lift and hold a bomb steady in its field-focus at seven hundred and fifty thousand feet. But if a bomb was accelerated all the way out to that point, and the field was then snapped off…Why, it wasn’t held anywhere! It kept on going with its attained velocity. And it burst when its fuse decided that it should, whereupon immediately a mass of sodium and potassium vapor, mixed with the fumes of high explosive, flung itself madly in all directions, out between the stars. Absolute vacuum tore the compressed gasified metals apart. The separate atoms, white-hot from the explosion, went swirling through sunlit space. The sunlight was dimmed a trifle, to be sure. But individual atoms of the lighter alkaline-earth metals have marked photoelectric properties. In sunshine these gas-molecules ionized, and therefore spread more widely, and did not coalesce into even microscopic droplets.

  They formed, in fact, a cloud in space. An ionized cloud, in which no particle was too large to be responsive to the pressure of light. The cloud acted like the gases of a comet’s tail. It was a comet’s tail, though there was no comet. And it was an extraordinary comet’s tail because it is said that you can put a comet’s tail in your hat, at normal atmospheric pressure. But this could not have been put in a hat. Even before it turned to gas, it was the size of a basketball. And, in space, it glowed.

  It glowed with the brightness of the sunshine on it, which was light that would normally have gone away through the interstellar dark. And it filled one comer of the sky. Within one hour it was a comet tail ten thousand miles long, which visibly brightened the daytime heavens. And it was only the first of such reflecting clouds.

  The next bomb set for space exploded in a different quarter, because Bordman had had the miniature grid wrestled around the upcrop to point in a new and somewhat more carefully chosen line. The next spattered brilliance in a different section still. And the brilliance lasted.