уI guess you know what Iтm thinking right now,ф he said awkwardly. -
Massy flushed. It was not dignified for a Colonial Survey officer to show off. He felt that Herndon was unduly impressed. But Herndon didnтt see that the device wouldnтt solve anything. It would merely postpone the effects of a disaster. It could not possibly prevent them.
уIt ought to be done,ф he said curtly. уThereтll be other things to be done, too.ф
уWhen you tell them to me,ф said Herndon warmly, уtheyтll get done! Iтll have Riki put this into that pulsecode you explained to us and sheтll get it off right away!ф
He stood up.
уI didnтt explain the code to her!ф insisted Massy. уShe was already translating it when you gave her my suggestion!ф
уAll right,ф said Herndon. уIтll get this sent back at once!ф
He hurried out of the office. This, thought Massy irritably, is how reputations are nade, I suppose. Iтm getting one. But his own reaction was extremely inappropriate. If the people of Lani II did suspend helicopter-supported grids of wire in the atmosphere, they could warm masses of underground rock and stone and earth. They could establish what were practically reservoirs of life giving heat under their cities. They could contrive that the warmth from below would rise only as it was needed. But. . .
Two hundred days to conditions corresponding to the colony-planet. Then two thousand days of minimum heat conditions. Then very, very slow return to normal temperature, long after the sun was back to its previous brilliance. They couldnтt store enough heat for so long. It couldnтt be done. It was ironic that in the freezing of ice and the making of glaciers the planet itself could store cold.
And there would be monstrous storms and blizzards on Lani II as it cooled. As cold conditions got worse the wire grids could be held aloft for shorter and shorter periods, and each time they would pull down less power than before. Their effectiveness would diminish even faster than the need for effectiveness increased.
Massy felt even deeper depression as be worked out the facts. His proposal was essentially futile. It would be encouraging, and to a very slight degree and for a certain short time it would palliate the situation on the innerplanet. But in the long run its effect would be zero.
He was embarrassed, too, that Herndon was so admiring. Herndon would tell Riki that he was marvelous. She mightўthough cagilyўbe inclined to agree. But he wasnтt marvelous. This trick of a flier-supported grid was not new. It had been used on Saril to supply power for giant peristaltic pumps emptying a polder that had been formed inside a ring of indifferently upraised islands.
All 1 know, thought Massy bitterly, is what somebodyтs showed me or Iтve read in books. And nobodyтs showed or written how to handle a thing like this! He went to Herndonтs desk. Herndon had made a new graph on the solar-constant observations forwarded from home. It was a strictly typical curve of the results of coinciding cyclic changes. 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. Massy took a pencil, frowning unhappily. 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 1Vўthe nearest other inhabited worldўwhen the 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. But 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 sunтs photosphere varies not as the square or cube, but as the fourth power of its absolute temperaturС. A very small change in the sunтs effective temperature, producible by sunspots, could make an altogether disproportionate difference in the warmth its worlds received. Massyтs 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. But there was 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, Massy reluctantly arrived at the fact that here, on this already frozen world, the temperature would drop 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 surroundingsў 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, Massy found himself thinking, if Riki wonтt leave when the Survey ship comes, Iтll resign from the Service. Iтll have to if iтm to stay. And I wonтt go unless she does.
III
уIf yOu want to come, itтs all right,ф said Massy ungraciously.
He waited while Riki slipped into the bulky coldgarments that were needed out-of-doors in the daytime, 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 the airpuffed, insulated over-tunic with its hood and mittens which were a part of the sleeves.
уNobody goes outside at night,ф she said when they stood together inthe cold-lock.
уI do,ф he told her. уI want to find out something.ф The outer door opened and he stepped out. He hНld his arm for her, because the steps and walkway were no longer heated. Now they were covered with a filmy layer of- something which, was not frost, but a faint, faint bloom of powder. It was the equivalent of dust, but it was miscroscopic 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 eardrums.
Massy threw back his head and gazed at the sky for a very long time. Nothing. He looked down at Riki.
уLook at the sky,ф 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 its sundogsўpale phantoms of itself ranged about itўso 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 oneтs eyes strove instinctively to grasp the greater pattern in which such seeming artifacts must belong.
уOh . . . beautiful!ф cried Riki softly, yet almost afraid.
уLook!ф he insisted. уKeep looking!ф
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.
уItтs . . . beautiful!ф said Riki breathlessly. - уBut what must I look for?ф
уLook for what isnтt there,ф 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 grayish glow somewhere indefinite. It vanished. Then she realized.
уThereтs no aurora!ф she exclaimed.
уThatтs it,ф said Massy. уThereтve always been auroras here. But no longer. We may be responsible. I wish I thought it wise to turn everything back to reserve power for a while. We could find out. But we canтt afford it. There was just the faintest possible gray flickering just now. But there ought to be armies of light marching across the sky. The aurora hereўit was never missing! But itтs gone now.ф
уI . . . looked at it when we first landed,ф admitted Riki. уIt was unbelievable! But it was terribly cold, out of shelter. And it happened every night, so I said to myself Iтd look tomorrow, and then tomorrow again. So it got so I never looked at all.ф
Massy kept his eyes where the faint gray flickering had been. And once one realized, it was astonishing that the former nightly play of ghostly colors should be absent.
уThe aurora,ф he said dourly, уhappens 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 planetтs magnetic field. The auroraтs a phenomenon of ions. We tap the inonosphere a long way down from where it plays, but Iтm wondering if we stopped it.ф
уWe?ф said Riki, shocked. уWeўhumans?ф
уWe tap the ions of their charges,ф he said somberly, уthat the sunlight made by day. Weтre pulling in all the power we can. I wonder if weтve drained the aurora of its energy, too.ф
Riki was silent. Massy gazed, still searching. But he shook his head.
уIt could be,ф he said in a carefully detached voice. уWe didnтt draw much power by comparison with the amount that came. But the ionization is an ultraviolet effect. Atmospheric gases donтt ionize too easily. After all, if the solar constant dropped a very little, it might mean a terrific drop in the ultraviolet part of the spectrumўand thatтs 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 weтre drawing power from the little thatтs left.ф
Riki stood very still. The cold was horrible. Had therЪ 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 oneтs nostrils ached, and the inside of oneтs chest was aware of chill. Even through the cold-garments there was the feeling as of ice without.
уIтm beginning,ф said Massy, уto suspect that Iтm a fool. Or maybe Iтm 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 weтve drained the aurora of its light, weтre scraping the bottom of the barrel. And itтs a shallower barrel than one would suspect.ф
There was stillness again. Rild stood mousy-quiet. When she realizes what this means, thought Massy grimly, she wonтt admire me so much. Her brotherтs built me up. But iтve been a fool, figuring out excuses to hope. Sheтll see it.
уI think,ф said Riki quietly, уthat youтre telling me that after all we canтt store up heat, to live on, down in the mine.ф
уWe canтt,ф agreed Massy grimly. уNot much, nor long. Not enough to matter.ф
уSo we wonтt live as long as Ken expects?ф
уNot nearly as long,ф said Massy evenly. уHeтs hoping we can find out things to be useful back on Lani II. But weтll lose the power we can get from our grid long before even their new grids are useless. Weтll have to start using our reserve power a lot sooner. Itтll be goneўand us with itўbefore theyтre really in straits for living-heat.ф
Rikiтs teeth began to chatter.
