IV

During the last night of preparation, Massy 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 halfway 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

CO_{2}, 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 CO_{2}.

Where it wasn't, the cold of space moved down. If at ground-level the

thermometer read ever so slightly lower than one hundred and nine below

zero--why--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 and nine point three

was the critical reading. If it went down to that, it would plunge to a

hundred and fifty--two hundred degrees below zero! 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 quite simply

impossible, in any shelter and under any conditions. Even spacesuits

would not protect against an atmosphere sucking heat from it at that

rate. A spacesuit 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 Massy 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 Massy 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."

Massy said heavily:

"Has she got something to heat the air she breathes?"

"Naturally," said Herndon. He added curiously, "What's the matter?"

"We almost took our licking," Massy told him. "I'm afraid for tonight,

and tomorrow night, too. If the CO_{2} 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. We'll be all right!"

"I doubt it very much," said Massy. "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 Massy.

"Everything's set," said Herndon exuberantly. "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!"

Massy looked at him queerly. Then he said:

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

* * * * *

But he was very tired. He was not elated. _Riki can't be gotten away_,

he thought wearily, _and I'm not going to go because it isn't quite

fitting to go and leave her. They'll all be rejoicing presently, but

nothing's settled._ Then he thought with exquisite irony, _She thinks

I was inspired to genius by her, when I haven't done a thing I wasn't

taught or didn't get out of books!_

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.

Massy went out-of-doors. He stepped out of the cold-lock and gazed

about him. The sun seemed markedly paler, and now it had lost its

sun-dogs again. Ice crystals no longer floated in the almost congealed

air. The sky was dark. It was almost purple, and it seemed to Massy

that he could detect faint flecks of light in it. They would be stars,

shining in the daytime.

There seemed to be 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 Massy 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 singularly 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 Massy. "We'll go work it."

He moved heavily 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 him 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._

He had a very peculiar ache inside. A Survey officer is naturally

lonely. Massy had been lonely before he even entered the Service. He

hadn't had a feeling of belonging anywhere, or with anyone, and no

planet was really his home. Now he could believe that he belonged

with someone. But there was the slight matter of a drop in the solar

constant of an unimportant sol-type sun, and nothing could come of it.

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 breathlessly

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

farther still. When it reached one hundred and nine point three degrees

below zero at ground-level--why it would keep on falling indefinitely.

Then it wouldn't matter how much power could be drawn from the sky. The

colony would die.

* * * * *

One 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. It put the object on the stone. Massy traced cables

with his eyes. From the grid to the control board. From the board back

to the reserve-power storage cells, deep in the mountain.

"The grid's tuned to the bomb," said Riki breathlessly, close beside

him. "I checked that myself!"

The bearlike 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, Massy threw a switch.

There was a very tiny whining sound, and the wrapped, ridiculously

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. That was all.

Massy 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. Massy reversed the lift-switch. He counted and then switched the

power off. The small, thin whine ended.

He threw the power-intake switch, which could have been on all the

time. 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 Massy.

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 cloud. It seemed to

Massy, very quaintly, that it was no bigger than a man's hand. 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!"

He went pounding back, to gaze raptuously at the new position of a thin

black needle on a large white dial, and to make incoherent noises of

rejoicing as it moved very, very slowly toward higher and ever higher

readings.

But Massy looked puzzledly 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 Massy froze in every muscle. He stared at the cloud he had

made aloft, and his hands clenched in their mittens, and he swallowed

convulsively behind his cold-mask.

"Th-that's it," he said in a very queer voice indeed. "It's ... very

much like a comet. I'm glad you said that! We can make something even

more like a comet. We ... 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 Massy 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

second bomb showed up. They 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 enthusiasm. 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 photo-electric 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 corner of the sky. Within one hour it was a comet's 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

Massy'd had the miniature grid wrestled around the upcrop to point in a

new and somewhat more carefully chosen line. The third bomb spattered

brilliance in a different section still. And the brilliance lasted.

Massy flung his first bombs recklessly, because there could be more.

But he was desperately anxious to hang as many comet tails as possible

around the colony-planet before nightfall. He didn't want it to get any

colder.

And it didn't. In fact, there wasn't exactly any real nightfall on Lani

III that night.

The planet turned on its axis, to be sure. But around it, quite close

by, there hung gigantic streamers of shining gas. At their beginning,

those streamers bore a certain resemblance to the furry wild-animal

tails that little boys like to have hanging down from hunting-caps.

Only they shone. And as they developed they merged, so that there

was an enormous shining curtain about Lani III. There were draperies

of metal-mist to capture sunlight that should have been wasted, and

to diffuse very much of it to Lani II. At midnight there was only

one spot in all the night-sky where there was really darkness. That

was directly overhead--directly outward from the planet from the

sun. Gigantic shining streamers formed a wall, a tube, of comet-tail

material, yet many times more dense and therefore brighter--which

shielded the colony-world against the dark and cold, and threw upon it

a brilliant, warming brightness.

* * * * *

Riki maintained stoutly that she could feel the warmth from the sky,

but that was improbable. But certainly heat did come from somewhere.

The thermometer did not fall at all, that night. It rose. It was up to

fifty below zero at dawn. During the day--they sent out twenty more

bombs that second day--it was up to twenty degrees below zero. By the

day after, there was highly competent computation from the home planet,

and the concrete results of abstruse speculation, and the third day's

bombs were placed with optimum spacing for heating purposes.

And by dawn of the fourth day the air was a balmy five degrees below

zero, and the day after that there was a small running stream in the

valley at midday.

There was talk of stocking the stream with fish, on the morning the

Survey ship came in. The great landing-grid gave out a deep-toned,

vibrant, humming note, like the deepest possible note of the biggest

organ that could be imagined. A speck appeared very, very high up in a

pale-blue sky with trimmings of golden gas-clouds. The Survey ship came

down and down and settled as a shining silver object in the very center

of the gigantic red-painted landing-grid.

Later, her skipper came to find Massy. He was in Herndon's office. The

skipper struggled to keep sheer blankness out of his expression.

"What ... what the hell?" he demanded querulously of Massy. "This

is the damnest sight in the whole galaxy, and they tell me you're

responsible! There've been ringed planets before, and there've been

comets and who-knows what! But shining gas pipes aimed at the sun, half

a million miles across.... What the? There are two of them! Both the

occupied planets!"

Herndon explained with a bland succinctness why the curtains hung in

space. There was a drop in the solar constant--

The skipper exploded. He wanted facts! Details! Something to report!

And dammit, he wanted to know!

Massy was automatically on the defensive when the skipper shot his

questions to him. A Senior Colonial Survey officer is not revered by

the Survey ship-service officers. Men like Massy can be a nuisance to a

hard-working ship's officer. They have to be carried to unlikely places

for their work of checking over colonial installations. They have to be

put down on hard-to-get-at colonies, and they have to be called for,

sometimes, at times and places which are inconvenient. So a man in

Massy's position is likely to feel unpopular.

"I'd just finished the survey here," he said defensively, "when a cycle

of sunspot cycles matured. All the sunspot periods got in phase, and

the solar constant dropped. So I naturally offered what help I could to

meet the situation."

The skipper regarded him incredulously.

"But ... it couldn't be done!" he said blankly. "They told me how

you did it, but ... it couldn't be done! Do you realize that these

vapor-curtains will make fifty borderline worlds fit for use? Half a

pound of sodium-vapor a week!" He gestured helplessly. "They tell me

the amount of heat reaching the surface here has been upped by fifteen

per cent! D'you realize what _that_ means?"

"I haven't been worrying about it," admitted Massy. "There was a local

situation and something had to be done. I ... er ... remembered things,

and Riki suggested something I mightn't have thought of, and it's

worked out like this." Then he said abruptly: "I'm not leaving. I'll

get you to take my resignation back. I ... I think I'm going to settle

here. It'll be a long time before we get really temperate-climate

conditions here, but we can warm up a valley like this for

cultivation, and ... well ... it's going to be a rather satisfying

job. It's a brand-new planet with a brand-new ecological system to be

established----"

The skipper of the Survey ship sat down hard. Then the sliding door of

Herndon's office opened and Riki came in. The skipper stood up again.

Massy rather awkwardly made the introduction. Riki smiled.

"I'm telling him," said Massy, "that I'm resigning from the Service to

settle down here."

Riki nodded. She put her hand in proprietary fashion on Massy's arm.

The Survey skipper cleared his throat.

"I'm not going to take it," he said doggedly. "There've got to be

detailed reports on how this business works. Dammit, if vapor-clouds in

space can be used to keep a planet warm, they can be used to shade a

planet, too! If you resign, somebody else will have to come out here to

make observations and work out the details of the trick! Nobody could

be gotten here in less than a year! You need to stay here to build up

a report--and you ought to be available for consultation when this

thing's to be done somewhere else! I'll report that I insisted as a

Survey emergency--"

Riki said confidently:

"Oh, that's all right! He'll do that! Of course! Won't you?"

Massy nodded dumbly. He thought, _I've been lonely all my life. I've

never belonged anywhere. But nobody could possibly belong anywhere

as thoroughly as I'll belong here when it's warm and green and even

the grass on the ground is partly my doing. But Riki'll like for me

still to be in the Service. Women like to see their husbands wearing

uniforms._

Aloud he said:

"Of course. It ... really needs to be done. Of course, you realize that

there's nothing really remarkable about it. Everything I've done has

been what I was taught, or read in books."

"Hush!" said Riki. "You're wonderful!"