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 Massy. 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 Massy. 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 sideline, there would be increased conductivity from the normal ionosphere.
“Something like this was done centuries ago, back on Earth,” he explained carefully. “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 coldly:
“How long will those clouds last?”
“That high, three or four days,” Massy 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 crisply:
“Hup!” The significance was, “Let’s go!” Then somebody 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 had vanished., Massy 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 hungrily to demand a share in the job.
When he was alone again, Massy 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 was needed. Again it might postpone the death of twenty million people, but it would never, 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!”
Massy writhed internally. It wasn’t wonderful.
“Consider,” he said in a desperate attempt to take it lightly, “consider that I’ve taken a vow.”
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, rather gravely. Then she said, “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 help 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!”
Massy swallowed.
“I’m afraid,” he said miserably, “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 come in, and … and if you think you can get me kidnaped to safety … without even telling me that you ‘rather like’ me, like you told my brother, or that I’m ‘pretty wonderful’—If you’ think.”
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?”
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 CO2, where the temperature was plummeting.
The height to which carbon dioxide existed was dropping—slowly, but inexorably. And above the carbondioxide 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 lower than one hundred and nine below zero—why—everything was finished. Without the greenhouse effect, the nightside 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 Hemdon came for him.
“Your phone-plate’s been flashing,” said Herndon, “and you didn’t answer. Must have bad 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.”