Timothy Zahn - Cascade Point

"But it's not like a real, stationary cloud," Rurik objected. "It's self- regenerating, more on the order of a bathtub with a faucet at one end and a drain at the other."

"Exactly. So we're going to enlarge the drain. What is the cloud composed of, gentlemen?"

"Subatomic particles," Galton said. "Positive and neutral, mostly."

"Right," Carter agreed. "Why no negative ones? Because the positive plates that hold Firefly itself in place rip away any negatives as soon as they're formed. Conversely, the plates tend to keep the positives near Firefly. The neutrals don't care either way." He handed a sketch to Mahler. "Felix, I propose setting up a pair of negatively charged plates a few meters from Firefly and where they won't block the neutron beams. What I want is to set up an extra electric field that will pull the positive particles away from Firefly without risking moving the black hole itself. Can it be done?"

Mahler frowned at the sketch for a moment. "It'll be tricky," he said. "Any extra charge near Firefly will change the field of the main plates. What we need is stable equilibrium right at Firefly's position and a small nonzero field a few angstroms away. We'll probably need curved electrodes of some kind; the computer can figure the shape for us."

"But be damn careful with that field," Rurik spoke up. "The black hole has got to be at a stable equilibrium point or we'll lose it."

"I'll set up the programming myself," Mahler said, making notes beside Carter's sketch.

"Doc, what about the neutral particles?" Rossetti asked.

"I think we're stuck with them," Carter admitted. "But if we can decrease the density of positives even a little it may be enough." The excitement he had felt a few minutes before was wearing off and fatigue was beginning to pull at him. It was an effort to continue speaking. "If there are no further questions let's get to work. Felix, get those plates designed and built as soon as possible. The rest of you assist him or stay out of his way. That's all, then. Paul, I'll meet you in the control room in a few minutes."

Carter had intended only to rest his eyes for a moment before rejoining the others. It was with some shock, therefore, that he dragged himself from a nightmarish dream two hours later to find himself still sitting at the deserted conference-room table. Blinking the sleep from his eyes, he pulled out his intercom. "Carter to control room," he said thickly.

"Rurik here, Ray." "What's going on up there? Why did you let me sleep this long?"

"We thought you needed the rest. The new electrodes have been made and tested, and Galton and Telemann have just about got them in place. There's nothing you need to do for at least a couple of more hours. Why don't you go back to sleep?"

"In a minute." Sleep was beginning to fog his brain again, but what he had to say was vital. "Paul, when they're finished out there I want you to set up those X- ray lasers to fire at Firefly."

"But the photons don't carry enough mass to make any real difference. Remember?"

"Don't care about the mass. The X-ray photons will get trapped into orbits around Firefly, either spiraling in or being absorbed by particles in the cloud. Most of those particles will be neutrals, since we're pulling away the others. Any particle that absorbs a photon will gain its kinetic energy and momentum."

"I understand," Rurik nodded excitedly. "The neutrals will tend to move away from the black hole faster. Just like heating up a gas and making it expand, really."

"Right. I admit it'll be a small effect—Firefly's own X-ray output is heating up that particle cloud far more than our lasers could ever hope to—but it may be worth doing, anyway."

"Agreed. We'll get on that right away."

Deep in Carter's subconscious the decision was made that he had done all that he could and that Firefly's fete was now in the hands of the universe. He barely managed to turn off his intercom before he was once more deeply asleep.

—

It was another four hours before he again awoke. This time he had the strength to go to the control room. One look at the meters was enough. "We did it," he murmured, half to himself.

Rurik swiveled in his seat at the main board. "You're awake," he said unnecessarily. "Yes, thanks to you. Firefly's temperature is dropping steadily. We've already cut the DeVegas back to safe flux levels, and will probably be able to shut off that extra field soon. Just as well, since the two electrodes are in pretty bad shape already from radiation damage."

"That reminds me. Did you tell me Galton was helping to install the new plates?"

Rurik lowered his eyes. "He insisted on going. I think he felt—well, responsible for the runaway." "He's an operator, not a tech," Carter growled. "He had no business going out there." He looked around the room. "Where is he, anyway?"

There was a long moment of silence. Then Rossetti spoke up quietly. "He and Telemann are both in intensive care, Doc. Severe radiation burns. They're not sure either will make it."

Carter stared at him, a cold fist squeezing his heart. "Oh, God. I never even thought of that."

"They knew the risk," Rurik said. "They also knew it had to be done."

"A high price to pay, but it bought the lives of Earths billions," Senator Chou added.

Carter turned to face him, anguish turning to unreasoning fury. "And I guess that's what matters to you, isn't it? That and closing down the Firefly Project. Well, you've got plenty of new ammunition now, don't you? So go ahead—tell the Council, hold your news conference, and get everyone screaming for the Project to be shut down. Then what are you going to do, demand we put as much mass as we can into Firefly and try to push it out of the system before it blows?—never mind that that's more dangerous than keeping it here."

He stopped, out of breath. In a quiet voice the Senator said, "The Council must be told, certainly. But there will be no news conference. The people of Earth must never know what almost happened."

The anger and frustration rising within Carter vanished at the unexpected answer. He stared hard at Chou, a dozen questions swarming through his mind. Only one got out: "Why?"

"Because you were right, Doctor. I've spent some time in the last few hours studying the figures. Without Firefly Earth would spend nearly eight percent of its resources over the next four decades in building new energy supplies, and we just can't afford that. There are too many problems that will take our full attention to solve. Like it or not, we need Firefly." He waved toward the control board. "Oh, I will push strongly for more safety precautions—running Firefly at a lower temperature, for example. But you have proved that the black hole can be handled, with the right man in charge." He must have seen something in Carters face, for his eyes narrowed slightly. "You do want to stay, don't you?"

Carter turned toward the port, looking through it as if he could see through the shielding and collectors at the impossibly brilliant pinprick in space that was Firefly. Once he had seen it as a servant, even a friend. But it had turned on him once, and he would never again be able to look upon it without knowing the acrid taste of fear.

He took a deep breath. "I'll have to think about it," he said. Afterword

This one grew out of a series of five lectures on black holes given at the University of Illinois by a visiting astrophysicist in the spring of 1979. After filling a notebook with more facts, figures, numbers, and equations on black holes than any sane layman could possibly want or need, I figured the least I could do was to get a story out of it. Maybe more than one—I'll have to check those notes one of these days and see what else is lurking in there.

As a matter of historical interest, the black hole Firefly was originally named Shiva. Elinor Mavor, then editor of Amazing, asked me to change it to avoid comparisons (or confusion) with the Gregory Benford/William Rotsler novel Shiva Descending. I've never felt Firefly was as aesthetically pleasing a name as Shiva, but it was the best of the twenty-odd alternatives I came up with. Writing, like politics, is often the art of compromise.