The Planet Explorer

by Murray Leinster

  He went to Herndon's desk. Herndon had made a new graph of the solar-constant observations forwarded from home. It was a strictly typical curve of the results of coinciding cyclic change. It was the curve of a series of frequencies at the moment when they were all precisely in phase. From this much one could extrapolate and compute.

  Bordman took a pencil, frowning. His fingers clumsily formed equations and solved them. The result was just about as bad as it could be. The change in brightness of the sun Lani would not be enough to be observed on Kent IV, the nearest other inhabited world, when light reached there four years from now. Lani would never be classed as a variable star, because the total change in light and heat would be relatively minute. The formula for computing planetary temperatures is not simple. Among its factors are squares and cubes of the variables. Worse, the heat radiated from a sun's photosphere varies not as the square or cube, but as the fourth power of its absolute temperature.

  Bordman's computations were not pure theory. The data came from Sol itself, where alone in the galaxy there had been daily solar-constant measurements for three hundred years. The rest of his deductions were based ultimately on Earth observations, too. Most scientific data had to refer back to Earth to get an adequate continuity. And there could be no possible doubt about the sunspot data, because Sol and Lani were of the same type and nearly equal size.

  Using the figures on the present situation, Bordman reluctantly arrived at the fact that here, on this already-frozen world, the temperature would drop gradually until CO2 froze out of the atmosphere. When that happened, the temperature would plummet until there was no really significant difference between it and that of empty space. It is carbon dioxide which is responsible for the greenhouse effect, by which a planet is in thermal equilibrium only at a temperature above its surroundings, as a greenhouse in sunlight is warmer than the outside air.

  The greenhouse effect would vanish soon on the colony world. When it vanished on the mother planet....

  Bordman found himself thinking, if Riki won't leave when the Survey ship comes, I'll resign from the Service. I'll have to if I'm to stay. And I won't go unless she does.

  * * * *

  “If you want to come, it's all right,” said Bordman ungraciously.

  He waited while Riki slipped into the bulky cold-garments that were needed out-of-doors in the daylight, and were doubly necessary at night. There were heavy boots with inches-thick insulating soles, made in one piece with the many-layered trousers. There was an air-puffed, insulated over-tunic with its hood and mittens which were a part of the sleeves.

  “Nobody goes outside at night,” she said when they stood together in the cold-lock.

  “I do,” he told her. “I want to find out something."

  The outer door opened and he stepped out. He held his arm for her, because the steps and walkway were no longer heated. Now they were covered with a filmy layer of powder—microscopic snow-crystals frozen out of the air by the unbearable chill of night.

  There was no moon, of course, yet the ice-clad mountains glowed faintly. The drone-hulls arranged in such an orderly fashion were dark against the frosted ground. There was silence, stillness, the feeling of ancient quietude. No wind stirred anywhere. Nothing moved, nothing lived. The soundlessness was enough to crack the ear-drums.

  Bordman threw back his head and gazed at the sky for a very long time. Nothing. He looked down at Riki.

  “Look at the sky,” he commanded.

  She raised her eyes. She had been watching him. But as she gazed upward she almost cried out. The sky was filled with stars in innumerable variety. But the brighter ones were as stars had never been seen before. Just as the sun in daylight had been accompanied by sun-dogs—pale phantoms of itself ranged about it—so the brighter distant suns now shone from the center of rings of their own images. They no longer had the look of random placing. Those which were most distinct were patterns in themselves, and one's eye strove instinctively to grasp the greater pattern in which such seeming artifacts must belong.

  “Oh—beautiful!” cried Riki softly.

  “Look!” he insisted. “Keep looking."

  She continued to gaze, moving her eyes about hopefully. It was such a sight as no one could have imagined. Every tint and every color, every possible degree of brightness appeared. And there were groups of stars of the same brilliance which almost made triangles, but not quite. There were rose-tinted stars which almost formed an arc, but did not. And there were arrays which were almost lines and nearly formed squares and polygons, but never actually achieved them.

  “It's beautiful,” said Riki. “But what must I look for?"

  “Look for what isn't there,” he ordered.

  She looked, and the stars were unwinking, but that was not extraordinary. They filled all the firmament, without the least space in which some tiny sparkle of light was not to be found. But that was not remarkable, either. Then there was a vague flickering graying glow somewhere, indefinite. It vanished. Then she realized.

  “There's no aurora!” she exclaimed.

  “That's it,” said Bordman. “There've always been auroras here. But no longer. We may be responsible. I wish I thought it wise to turn everything back to reservoir power for a while. We could find out. But we can't afford it."

  “I looked at it when we first landed,” admitted Riki. “It was unbelievable. But it was terribly cold, out of shelter. And it happened every night, so I said to myself I'd look tomorrow, and then tomorrow again. So it got so I never looked at all."

  Bordman kept his eyes where that faint gray flickering had been. And, once one realized, it was astonishing that the former nightly play of ghostly color should be absent.

  “The aurora,” he said, “happens in the very upper limits of the air, fifty—seventy—ninety miles up, when God-knows-what emitted particles from the sun come streaking in, drawn by the planet's magnetic field. The aurora's a phenomenon of ions. We tap the ionosphere a long way down from where it plays, but I'm wondering if we stopped it."

  “We?” said Riki, shocked. “We humans?"

  “We tap the ions of their charges,” he said somberly, “that the sunlight made by day. We're pulling in all the power we can. I wonder if we've drained the aurora of its energy, too."

  Riki was silent. Bordman gazed, still searching. But he shook his head.

  “It could be,” he said in a carefully detached voice. “We didn't draw much power by comparison with the amount that came. But the ionization is an ultra-violet effect. Atmospheric gases don't ionize too easily. After all, if the solar constant dropped a very little, it might mean a terrific drop in the ultra-violet part of the spectrum—and that's what makes ions of oxygen and nitrogen and hydrogen and such. The ion-drop could easily be fifty times as great as the drop in the solar constant. And we're drawing power from the little that's left."

  Riki stood very still. The cold was horrible. Had there been a wind, it could not have been endured for an instant. But the air was motionless. Yet its coldness was so great that the inside of one's nostrils ached, and the inside of one's chest was aware of chill. Even through the cold-garments there was the feeling as of ice without.

  “I'm beginning,” said Bordman, “to suspect that I'm a fool. Or maybe I'm an optimist. It might be the same thing. I could have guessed that the power we could draw would drop faster than our need for power increased. If we've drained the aurora of its light, we're scraping the bottom of the barrel. And it's a shallower barrel than one would suspect."

  There was stillness again. Riki stood mousy-quiet. When she realized what this means, thought Bordman grimly, she won't admire me so much. Her brother's built me up. But I've been a fool, figuring out excuses to hope. She'll see it.

  “I think,” said Riki, “that you're telling me that after all we can't store up heat to live on, down in the mine."

  “We can't,” agreed Bordman. “Not much, nor long. Not enough to matter."

  “So we won't live as long as Ken
expects?"

  “Not nearly as long,” said Bordman. “He's hoping we can find out things to be useful back on Lani II. But we'll lose the power we can get from our grid long before even their new grids are useless. We'll have to start using our reserve power a lot sooner. It'll be gone—and us with it—before they're really in straits for living-heat."

  Riki's teeth began to chatter.

  “This sounds like I'm scared,” she said angrily, “but I'm not! I'm just freezing. If you want to know, I'd a lot rather have it the way you say. I won't have to grieve over anybody, and they'll be too bust to grieve for me ... Let's go inside while it's still warm."

  He helped her back into the cold-lock, and the outer door closed. She was shivering uncontrollably when the warmth came pouring in.

  They went into Herndon's office. He came in as Riki was peeling off the top part of her cold-garments. She still shivered. He glanced at her and said to Bordman:

  “There's been a call from the grid-control shack. It looks like there's something wrong, but they can't find anything. The grid is set for maximum power-collection, but it's bringing in only fifty thousand kilowatts!"

  “We're on our way back to savagery,” said Bordman, with an attempt at irony.

  It was true. A man can produce two hundred fifty watts from his muscles for a reasonable length of time. When he had no more power, he is a savage. When he gains a kilowatt of energy from the muscles of a horse, he is a barbarian, but the new power cannot be directed wholly as he wills. When he can apply it to a plow he has high barbarian culture, and when he adds still more he begins to be civilized. Steam-power put as much as four kilowatts to work for every human being in the first industrialized countries, and in the mid-twentieth century there were sixty kilowatts per person in the more advanced nations. Nowadays, of course, a modern culture assumed five hundred as a minimum. But there was less than half that in the colony on Lani III. And its environment made its own demands.

  “There can't be any more,” said Riki, trying to control her shivering. “We're even using the aurora and there isn't any more power. It's running out. We'll go even before the people at home, Ken."

  Herndon's features looked pinched.

  “But we can't! We mustn't!” He turned to Bordman. “We do them good, back home! There was panic. Our report about cable grids has put heart in people. They're setting to work magnificently! So we're some use. They know we're worse off then they are, and as long as we hold on they'll be encouraged. We've got to keep going somehow!"

  Riki breathed deeply until her shivering stopped. Then she said:

  “Haven't you noticed, Ken, that Mr. Bordman has the viewpoint of his profession? His business is finding things wrong. He was deposited in our midst to detect defects in what we did and do. He has the habit of looking for the worst. But I think he can turn the habit to good use. He did turn up the idea of cable-grids."

  “Which,” said Bordman, “turns out to be no good at all. They'd be some good if they weren't needed, really. But the conditions that make them necessary make them useless!"

  Riki shook her head.

  “They are useful!” she said. “They're keeping people at home from despairing. Now, though, you've got to think of something else. If you think of enough things, one will do good the way you want, more than just making people feel better."

  “What does it matter how people feel?” he demanded bitterly. “What difference do feelings make? One can't change facts!"

  Riki said firmly:

  “We humans are the only creatures in the universe who don't do anything else. Every other creature accepts facts. It lives where it is born, and it feeds on the food that is there for it, and it dies when the facts of nature require it to. We humans don't. Especially the women! We won't let men do it, either. When we don't like facts—mostly about ourselves—we change them. But important facts we disapprove of—we ask men to change them for us. And they do!"

  She faced Bordman. Rather incredibly, she grinned at him.

  “Will you please change the facts that look so annoying just now, please? Please?” Then she elaborately pantomimed an over-feminine girl's look of wide-eyed admiration. “You're so big and strong! I just know you can do it—for me!"

  She abruptly dropped the pretense and moved toward the door. She half-turned then, and said detachedly:

  “But about half of that is true."

  The door slid shut behind her. It suddenly occurred to Bordman that she knew a Colonial Survey ship was due to stop by here to pick him up. She believed he expected to be rescued, even though the rest of the colony could not be, and most of it wouldn't consent to leave their kindred when the death of mankind in this solar system took place. He said awkwardly:

  “Fifty thousand kilowatts isn't enough to land a ship."

  Herndon frowned. Then he said:

  “Oh. You mean the Survey ship that's to pick you up can't land? But it can go in orbit and put down a rocket landing-boat for you."

  “I wasn't thinking of that. I'd something more in mind. I—rather like your sister. She's pretty wonderful. But there are some other women here in the colony, too. About a dozen all told. As a matter or self-respect I think we ought to get them away on the Survey ship. I agree that they wouldn't consent to go. But if they had no choice—if we could get them on board the grounded ship, and they suddenly found themselves—well—kidnapped and outward-bound not by their own fault ... They could be faced with the accomplished fact that they had to go on living."

  Herndon said evenly:

  “That's been in the back of my mind for some time. Yes, I'm for that. But the Survey ship can't land—"

  “I believe I can land it regardless,” said Bordman. I can find out, anyhow. I'll need to try things. I'll need help. But I want your promise that if I can get the ship to ground you'll conspire with her skipper and arrange for them to go on living."

  Herndon looked at him.

  “Some new stuff, in a way,” said Bordman uncomfortably. “I'll have to stay aground to work it. It's also part of the bargain that I shall. And of course your sister can't know about it, or she can't be fooled into living."

  Herndon's expression changed a little.

  “What'll you do? Of course it's a bargain."

  “I'll need some metals we haven't smelted so far,” said Bordman. “Potassium if I can get it, sodium if I can't, and at worst I'll settle for zinc. Cesium would be best, but we've found no traces of it."

  Herndon said thoughtfully:

  “No-o-o. I think I can get you sodium and potassium, from rocks. I'm afraid no zinc. How much?"

  “Grams,” said Bordman. “Trivial quantities. And I'll need a miniature landing-grid built. Very miniature."

  Herndon shrugged his shoulders.

  “It's over my head. But just to have work to do will be good for everybody. We've been feeling more frustrated here than any other humans in history. I'll go round up the men who'll do the work. You talk to them."

  The door closed behind him. Bordman got out of his cold-clothing. He thought, She'll rage when she finds her brother and I have deceived her. Then he thought of the other women. If any of them are married, we'll have to see if there's room for their husbands. I'll have to dress up the idea. Make it look like reason for hope, or the women would find out. But not many can go....

  He knew roughly how many extra passengers could be carried on a Survey ship, even in such an emergency as this. Living-quarters were not luxurious, at best. Everything was cramped and skimped. Survey ships were rugged, tiny vessels, which performed their duties amid tedium and discomfort and peril for all on board. But one of them could carry away a very few unwilling refugees to Kent IV.

  He settled down at Herndon's desk to work out the thing to be done.

  It was not unreasonable. Tapping the ionosphere for power was something like pumping water out of a pipe-well in sand. If the water-table was high, there was pressure to force the water to the pipe, and one could pump fast. If th
e water-table was low, water couldn't flow fast enough. The pump would suck dry. In the ionosphere, the level of ionization was at once like the pressure and the size of the sand-grains. When the level was high, the flow was vast because the sand-grains were large and the conductivity high. But as the level lessened, so did the size of the sand-grains. There was less to draw, and more resistance to its flow.

  However, there had been one tiny flicker of auroral light over by the horizon. There was still power aloft. If Bordman could in a fashion prime the pump, if he could increase the conductivity by increasing the ions present around the place where their charges were drawn away, he could increase the total flow. It would be like digging a brick well where a pipe well had been. A brick well draws water from all around its circumference.

  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 over 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.