Tower of Glass

“No. There has to be continuity. They couldn’t have reached a technological level that would allow them to send transgalactic messages at all unless they were able to retain the achievements of earlier generations.”

Krug swung round. “You know something? This planetary nebula, this blue sun — I still don’t believe it could have intelligent beings living there. Any kind of life — no! Listen, blue suns don’t last long, Vargas. It takes millions of years for the surface of a planet just to cool enough to get solid. There isn’t that much time, a blue sun. Any planets it’s got, they’re still molten. You want me to believe signals coming from people who live on a fireball?”

Vargas said quietly, “Those signals come from NGC 7293, that planetary nebula in Aquarius.”

“For sure?”

“For sure. I can show you all the data.”

“Never mind. But how, a fireball?”

“It’s not necessarily a fireball. Maybe some planets cool faster than others. We can’t be sure how long it takes them to cool. We don’t know how far the home world of the message-senders is from that sun. We’ve got models showing the theoretical possibility that a planet can cool fast enough, even with a blue sun, to allow—”

“It’s a fireball, that planet,” said Krug sullenly.

Defensive now, Vargas said, “Perhaps. Perhaps not. Even if it is: must all life-forms live on a solid-surface planet? Can’t you conceive a civilization of high-temperature entities evolving on a world that hasn’t cooled yet? If—”

Krug snorted in disgust. “Sending signals with machines made of molten steel?”

“The signals don’t have to be mechanical in origin. Suppose they can manipulate the molecular structure of—”

“You talk fairy tales to me, doctor. I go to a scientist, I get fairy tales!”

“At the moment fairy tales are the only way of accounting for the data,” Vargas said.

“You know there’s got to be a better way!”

“All I know is that we’re getting signals, and they undoubtedly come from this planetary nebula. I know it isn’t plausible. The universe doesn’t have to seem plausible to us all the time. Its phenomena don’t have to be readily explicable. Transmat wouldn’t be plausible to an eighteenth-century scientist. We see the data as best we can, and we try to account for it, and sometimes we do some wild guessing because the data we’re getting doesn’t seem to make sense, but—”

“The universe doesn’t cheat,” Krug said. “The universe plays fair!”

Vargas smiled. “No doubt it does. But we need more data before we can explain NGC 7293. Meanwhile we make do with fairy tales.”

Krug nodded. He closed his eyes and fondled dials and meters, while within him a monstrous raging impatience sizzled and blazed and bubbled.Hey, you star people! Hey, you, sending those pulses! Who are you? What are you? Where are you? By damn, I want to know!

What are you trying to tell us, you?

Who are you looking for?

What’s it all mean? Suppose I die before I find out!

“You know what I want?” Krug said suddenly. “To go outside, to that radio telescope of yours. And climb up into the big dish. And cup my hands and shout at those bastards with the numbers. What’s the signal now? 2-5-1, 2-3-1, 2-1? It drives me crazy. We ought to answer them right now. Send some numbers: 4-10-2, 4-6-2, 4-2. Just to show them we’re here. Just to let them know.”

“By radio transmission?” Vargas said. “It’ll take 300 years. The tower will be finished soon.”

“Soon, sure. Soon. You ought to see it. Come see, next week. They’re putting the gadgets in it now. We’ll be talking to the bastards soon.”

“Would you like to hear the audio signal coming in, the new one?”

“Sure.”

Vargas touched a switch. From speakers in the laboratory wall came a dry cold hiss, the sound of space, the voice of the dark abyss. It was a sound like a cast-off snakeskin. Overriding that withered sound, seconds later, came sweet upper-frequency tones.Pleep pleep. Pause.Pleep pleep pleep pleep pleep. Pause.Pleep. Pause. Pause.Pleep Pleep. Pause.Pleep pleep pleep. Pause.Pleep. Pause. Pause.Pleep pleep. Pause.Pleep. Silence. And then again,pleep pleep, the new cycle begi

“Beautiful,” Krug whispered. “The music of the spheres. Oh, you mysterious bastards! Look, doctor, you come see the tower next week, next — oh, Tuesday. I’ll have Spaulding call you. You’ll be amazed. And listen, anything else new comes up, another change in the signal, I want to hear right away.”

Pleep pleep pleep.

He headed for the transmat.

Pleep.

Krug leaped northward along the meridian, following the line of 90 DEGREES E., looped the North Pole, and emerged beside his tower. He had sped from icy plateau to icy plateau, from the world’s bottom to its top, from late spring to early winter, from day to night. Androids were busy everywhere. The tower seemed to have grown fifty meters since yesterday’s visit. The sky was ablaze with the light of reflector plates. The song of NGC 7293 sang seductively in Krug’s mind.Pleep pleep pleep.

He found Thor Watchman in the control center, jacked in. The alpha, unaware of Krug’s presence, seemed lost in a drugged dream, climbing the precipices of some distant interface. An awed beta offered to cut into the circuit and tell Watchman, via the computer, that Krug had arrived. “No,” Krug said. “He’s busy. Don’t bother him.”Pleep pleep pleep pleep pleep. He stood for a few moments, watching the play of expressions on Watchman’s tranquil face. What was passing through the alpha’s mind now? Freight invoices, transmat manifests, welding cues, weather reports, cost estimates, stress factors, perso

Pleep pleep pleep. Pleep.

Affectionately, a little surprised at himself, he put his hands to Thor Watchman’s broad shoulders in a quick embrace. Then he went out. He stood in the frigid blackness a short while, surveying the frenzied activity at every level of the tower. On top they were putting new blocks in place with flawless rhythm. Inside, the tiny figures were hauling neutrino-sheathing around, joining lengths of copper cable, installing floors, carrying the heat-cool-power-light system higher and higher. Through the night came a steady pulsation of sound, all the noises of construction blending into a single cosmic rhythm, a deep booming hum with regular soaring climaxes. The two sounds, the i

He walked toward the transmats, ignoring the knives of the Arctic wind.

Not bad for a poor man without much education, he told himself. This tower. These androids. Everything. He thought of the Krug of forty-five years ago, the Krug growing up miserable in a town in Illinois with grass in the middle of the streets. He hadn’t dreamed much about sending messages to the stars then. He just wanted to make something out of himself. He wasn’t anything, yet. Some Krug! Ignorant. Ski