Cascade Point

The Energy Crisis of 2215

Its birth had been in the fiery turbulence of the primordial explosion, and for the billions of years since then the tiny black hole had drifted quietly through the expanding universe. Not once in all that time had it found itself closer than half a light-year to any star, much less approaching to within a few million miles as it was doing now. But there is a first time for everything.

Never very large to begin with, the black hole had steadily been losing mass during its long lifetime, and its gravitational effects were virtually undetectable even tens of meters away. But the strange laws which governed its existence required that a decrease in mass be accompanied by an increase in effective temperature, and so the black hole was now radiating energy and particles as if it were at a quadrillion degrees. Without this power output it might have slipped unnoticed through the solar system; as things were, it hadn't a hope of doing so.

The black hole was just crossing the orbit of Saturn when it was first detected by a routine gamma-ray scan. Identification came soon afterwards; and on Earth, Luna, Ceres, Hestia, and the Space Colonies debates were soon raging as to what should be done about the intruder. A large body of opinion was for letting the black hole continue unmolested along its hyperbolic path, or possibly even assisting it on its way out of the system. But others saw a unique opportunity in the chance meeting, and their views eventually prevailed, though at the cost of bitter feelings and many broken friendships.

The preparations took even longer than the debates had, but finally all was ready, and on January 1, 2215, the first of four specially designed space tugs matched orbits with the black hole and began pouring protons into it. As the intruders positive charge increased, the tugs used electric fields to nudge it from its original course and, eventually, into a stable orbit at one of the Earth-Luna Lagrangian points.

Project Firefly had begun. —

Dr. Ray Carter, Director of the Firefly Project, ran his eyes over the bank of monitor screens that wrapped themselves around the main control board like a lucky horseshoe. The glance was pure reflex; everything had been ready for the past two hours and the only thing holding up the works now were the speeches still going on from the main auditorium. He felt no impatience, though; if turning Day One into a media event would help sell Firefly to the public, it had Carters blessing. Glancing around the room, Carter noticed a familiar figure staring out the port into the blackness outside. Walking carefully in his Velcro shoes, he joined the other. "You can't see it from here, Senator," he remarked by way of greeting.

Senator Chou didn't turn. "I know," he said, his voice carefully neutral. Nodding toward the port, he continued, "It's two kilometers to the DeVega dipole accelerator platform, a hundred meters to the energy collector sphere, and another half kilometer to the black hole itself. And the whole thing a superbly engineered waste of money."

Carter winced slightly. Chou had always been one of the strongest opponents of Firefly, and Carter knew better than to try to argue with him. Apparently even coming over to say hello had been a mistake. "If you'll excuse me..."

Chou turned to face him. "Sorry. No real point in screaming about it now. But it wasn't necessary, you know. Fusion plants and solar power are quite adequate for Earths needs."

"For now, sure. But what about the future? Even at the present rate of increase we would have a hard time building enough fusion plants to supply our needs by the turn of the century."

"The sun will still be there."

"Sure will," Carter nodded. "And did you know you'd need a billion and a half square kilometers of solar collectors to generate as much power as Firefly will? That's about three times the Earths surface area, I believe. Excuse me, please."

Carter went back to the control board, his annoyance at Chou evaporating quickly. Rossetti, chief operator, looked up. "The Secretary-General is just about finished, Doc," he said.

"Good. How are the collectors doing?"

"Seem to be okay. Firefly's throwing off a lot of particles, both charged and neutral, but most of them are being collected, or at least stopped. Efficiency for charges is hovering near eighty-five percent; heat exchangers about half that."

Carter nodded. Firefly—the black hole was almost universally called by the name of the project nowadays—was behaving as expected, losing its mass in a thermal spectrum that included both photons and subatomic particles. The fast- moving charged particles were no problem; a set of electromagnetic fields at the collector sphere slowed them down to safe speeds, simultaneously converting their kinetic energy into electric current. The X rays and neutral particles were captured by a special multicomponent liquid blanket, their energy absorbed as heat to be changed into electricity by more indirect means. And for the ultra-high-energy gamma rays that passed through the collectors as if they were tissue paper, there were ten meters of shielding.

Pity we can't use the neutrinos, too, Carter thought wryly. Firefly's temperature, he noted, was still increasing, and he hoped the Secretary-General's speech wouldn't take much longer.

A yellow light flashed twice. They were ready in the auditorium. "Okay, Rossetti. Fire when ready."

"Aye, aye, Admiral." Rossetti's hands moved over the controls as Carter watched the indicators. Kilometers away, the three massive DeVega accelerators came to life, sending narrow beams of neutrons directly into the tiny black hole. Firefly's radiation levels jumped as the gravitational energy of the falling neutrons began to reach the collectors. Rossetti carefully adjusted the flux levels and Firefly's temperature began to stabilize.

"That's it, Doc," Rossetti said at last. "Total neutron flux about ten to the twenty-eighth per second; total Firefly luminosity one point six times ten to the eighteenth watts. Temperature holding near ten to the fifteenth degrees Kelvin. We've got steady state and she's running like a champ."

A loud cheer erupted in the control room, echoed, no doubt, in the auditorium. Someplace a cork popped loudly, accompanied by the steady hum of video cameras. Carter smiled for the reporters, his first real smile in weeks. After months of argument and backbreaking work, the closest thing to a total matter converter that mankind was ever likely to have was finally operational.

There were still things to be done, of course, but most of them were routine. He would first have to give a statement to the assembled dignitaries and cameras in the auditorium. Then came a check of the maser banks that would be beaming the energy to Earth and Luna, a quick trip to each of the DeVega accelerators to personally congratulate the operation crews there, and spot checks of other parts of the complex.

Five hours later he was finished, and he made a last stop back in the control room. "Any fluctuations in the plate potential?" he asked the dark-skinned man who had taken Rossetti's place at the main control board.

"No problems, Dr. Carter," Kapoor said, his gloomy face in marked contrast to the smiles worn by the rest of the Firefly Project staff today. "The black hole is holding position to a small fraction of a fermi, as nearly as we can tell."

Carter nodded satisfaction. The carefully shaped electric field of the main plates was all that held the positively charged black hole suspended in place at the focus of the three neutron beams. If it drifted even slightly the beams would miss the tiny object. "Anything else to report?"

"No, sir."

"Okay. Well, I'm off. See you in three weeks."

Kapoor glanced up. "You're going on vacation?"

"Theoretically, yes. Practically, it'll be one week of rest and two of speeches on Earth and Luna."

"It will be a nice change for you, anyway."

"Yes." Talking to Kapoor always depressed Carter a little. Something about the Indian's attitude seemed to indicate disapproval, although it was nothing you could put your finger on. As near as Carter could remember, Kapoor's geniality had evaporated during the Assembly's debates on a name for the project. It had come within a hair of being called Shiva, after the destroyer/regenerator of Hinduism, and Carter strongly suspected that Kapoor had considered even the suggestion to be sacrilegious. "Well, take care of the project, Kapoor," he said, a bit lamely, and left the room.

It could have been worse, Carter thought, walking down the hall. The Assembly had also considered the name Lucifer.

—

As things turned out, Carter was not away from Firefly for three weeks. He was gone for exactly fifty-eight hours, and the ship that returned him to the station was a big Patrol craft that made the trip in record time. No one aboard would tell him what was going on, but the message was painfully clear.

Something was terribly wrong at Firefly.

—

The entire senior staff was assembled in the conference room when Carter arrived and slid into his usual chair. Nodding to the group, he turned to the Deputy Director and asked, "What's happened, Paul?"

Dr. Paul Rurik looked like he was next in line for a oneway tumbril ride. "We may have a runaway on our hands, Ray."

Carter felt his hands tightening into fists under the table. "Fill me in."

Rurik touched a switch and a set of graphs appeared on one of the displays. "During last night's Owl shift Firefly's temperature started to rise. When we tried to restabilize this morning we discovered we couldn't do so. We tried everything we could think of and then sent the Patrol to get you." "Who was the operator last night?"

"I was, Doctor," a young man spoke up, a slight quaver in his voice.

"It wasn't Galton's fault," Rurik said. "The temperatures were within the allowable range we've calculated."

Carter nodded heavily. An operator couldn't be expected to notice that the rate of temperature increase was not following the theoretical curve. Only one of the scientists like Rurik or himself would have had the necessary knowledge.

Rurik went on, "I suspect Firefly drifted a little out of place, causing one or more of the neutron beams to miss it"

"No." Carter pointed to a display. "If that had happened you'd have gotten a big energy jump in the heat exchanger directly across from the beam that's missing. Instead, that extra neutron flux is spread out over several exchangers; furthermore, it's happening for all three beams. The beams aren't missing—they're being deflected."

"How?"

Carter looked toward the voice in surprise. "What are you doing here, Senator?"

"I was still here at Firefly when the crisis occurred," Chou said. "It is my right to be kept informed. How are the neutrons being deflected, Doctor?"

"Firefly emits particles in a thermal spectrum," Carter explained. "That means there are some at every speed from zero to near lightspeed. The ones that are moving slowly tend to stay near the black hole, forming a sort of cloud around it, and it's this cloud that's deflecting the beams."

"Surely they can't change the beam directions very much," Chou argued.

"They don't have to," Rurik put in. "Firefly is much smaller than the neutrons themselves. But, Ray, we took that effect into account when we set our temperature limits."

"I know. All I can think of is that our subatomic particle theory must be wrong somehow. If there are some particles coming out of Firefly that we haven't taken into account, all of our temperature curve calculations will be off."

"Hell cubed," Rurik muttered under his breath. "I'll get the theory people on this right away. Maybe with the extra particle emission data Firefly's giving them they can figure out where we're going wrong."

"For the moment, that won't help us," Carter said. "What we have to do is get more mass into Firefly, and that as soon as possible. The hotter it gets, the denser that particle cloud becomes. Not much, since most of the particles emitted have high kinetic energies, but even a slight increase in the number of low-energy particles just makes things worse. What have we got that we can throw at the black hole?"

"We have a spare DeVega accelerator," Rossetti volunteered, "but I don't think that'll help any."

"Why not?" Senator Chou asked. "That would give you an extra neutron beam."

For an instant Carter had an overpowering urge to tell the Senator to shut up. None of them had the time to explain things to a layman. "DeVega dipole accelerators require very tricky and sensitive electromagnetic fields to function. On a ring the diameter of the accelerator platform we can place only three DeVegas, spaced one hundred twenty degrees apart. Any closer and their fields would interfere with each other."

"What about putting the extra accelerator farther out from the center?" Chou persisted.

"At the distance we'd need the beam would spread out too much to be useful. And before you ask, directly above and below Firefly are the charged plates that hold it in place, so we can't run a neutron beam through there. Paul, can we increase present flux any?"

"No way. We're already running them ten percent above spec maximum, though I don't know how long they can hold that. We may in fact have stopped the runaway—the temperature is changing so slowly now we can't tell if it's going up or down."

"Let's assume it's still going up," Carter said. "Anything else we can use?"

"We've got a few X-ray lasers," someone said. "They could be set up to fire at Firefly."

"I've already checked that," Rossetti said. "It won't give a significant mass increment, and might add an extra scattering component to the neutron beams."

"Sir?" Galton spoke up hesitantly. "I may have an idea."

"Spit it out, son," Rurik said brusquely. "This is no time to be shy."

Carter winced at the tone as Galton blushed slightly. The young man's reticence was clearly not shyness, but instead the result of guilt feelings over his part in this mess. Rurik had never been good at understanding human emotion, though. He had declared that the fault was not Galton's and, for him, that ended the subject. It would never occur to him that Galton might still be upset.

"Sir, the DeVegas will accelerate any neutral particle that has a reasonable dipole moment. If we used, say, iron atoms instead of neutrons, we might be able to reverse the runaway."

Rurik nodded slowly. "That might just work, Galton. You'll probably get fewer hits on Firefly because of heightened beam self-interference diffusion, but the ones that go in are fifty-six times more massive. And they'll be deflected less by that particle cloud around Firefly." He looked at Carter inquiringly.

"It's worth a try," Carter agreed. "Anyone know how long it would take to switch beam materials?"

"I checked, sir," Galton said. "The beam would only have to be off for ten minutes. And there's enough spare iron around for about ten hours of operation."

"If we can't reverse the runaway in that time we'll have to try something else, anyway." But to have the beams off for even ten minutes might prove disastrous. Carter weighed the options briefly, painfully aware of the need for speed. "All right. Galton, get the DeVega crews together and brief them. We'll switch just one accelerator for now—make it Beta. If it helps, we'll do the other two a little later. Paul, I suggest you get the control room people ready for the switchover. The rest of you go to your Emergency posts—I want to be ready if any problems crop up. Get to it."

There was a mad scramble for the door, but as Carter turned to leave he found his way barred by Senator Chou. "Dr. Carter, a word with you, please."

"I'll be up in a minute," Carter called to Rurik over Chou's shoulder. Rurik nodded and glided from the room, not bothering to use his Velcro shoes. "What is it, Senator?" Carter said when the others had gone. "Make it fast, please. I'm in a hurry."

"What are our chances of stopping it, do you think?"

"Is that what you wanted? I have no idea. You'll just have to wait until the rest of us know."

"I can't wait for certainties—probabilities must do for now. I have a duty to the people of Earth. If anything goes wrong here we will have to begin taking steps to protect them, and the sooner we start the fewer will have to die."

Carter looked at Chou with new insight. For the past several months he had seen the Senator as simply an opponent, a cardboard cutout violently and irrationally opposed to the Firefly Project. Now, suddenly, Carter saw him as a human being. "You really care about Earth, don't you?" he said softly.

"It's my profession to care, Doctor. You may recall that I wanted the black hole placed a good distance further from Earth, where it would have been less of a danger to both the planet and the Space Colonies. I am not anti-technology, despite your side's efforts to paint me so, but I wished for a larger safety factor."

"Senator, there wasn't a decent safety factor available. If we can't stop the runaway, Earth has had it no matter where Firefly is."

"I don't understand."

Carter took a deep breath. "If we can't stabilize Firefly's temperature, it will keep getting hotter and hotter. The hotter it gets, the faster it radiates its mass as energy until it basically explodes. According to current theory, in the last tenth second of its existence it will radiate with one percent of the sun's total power output."

Chou's eyes were very wide. "Good Lord! And you allowed this—this nova to be placed in Earth orbit? You must be insane!"

"Senator, if Firefly lets go anywhere in the solar system Earth is finished. The sun will go crazy with all that extra radiation hitting it. If the extra solar heat doesn't sterilize the inner system, the extra radiation will. But we had no real choice in the matter. I don't think more than a handful of people realize this, but if we had just ignored the black hole from the very beginning the same thing probably would have happened. Firefly was already too close to blowing. We didn't deliberately put Earth in danger, Senator; we were trying very hard to save it. And we still are. Excuse me, but I have to get to the control room."

—

It was an hour later before Carter was satisfied that the DeVega accelerator crews had the technique down well enough to be able to switch beam materials in the shortest possible time. The Project's chief design engineer, Felix Mahler, floated by Carter's shoulder as the control-room personnel waited for word that the changeover had been completed.

"Santos and Trumbell are the best techs I've got," Mahler said into the brittle silence as the minutes ticked by. "If anyone can get the DeVegas going in ten minutes it's them. Matter of fact, Ray, I'll bet you they'll do it in nine."

The speaker crackled. "Beta station; Santos. We're ready here."

Rossetti, at the control board, didn't wait for Carter's nod. "Firing," he said.

"Eight and a half," Mahler muttered to no one in particular. "They're better than I thought."

Carter smiled slightly, but it was an automatic response. His full attention was on the meters that gave Firefly's luminosity and temperature, both of which had been running. The indicators jumped wildly, as always happened when a new beam was brought to strength, and Carter's heart rate jerked in sympathetic response.

"Beam's steadying down," Rossetti muttered.

"How's it look?" "It's hard to say, Doc. We're getting extra power just from the gravitational energy effects—since the iron atoms are heavier than neutrons—and that's fouling all our calibrations." Rossetti stared hard at the temperature indicator. "If Firefly's cooling down I can't tell from this. Not yet, anyway."

"We could shift the feed on the other DeVegas," Mahler suggested. "That would make any temperature change more visible."

"I'd rather not risk shutting off the neutron beams for the time that would take," Carter said. "Not until we're sure it'll do us any good. Let's give this an hour or so and see what happens."

—

The results after two hours were very clear. Firefly's temperature was still increasing.

"Damn!" Carter muttered through clenched teeth. "It's got to work. Galton's numbers prove that. What's going wrong?"

He threw a glance around the room, a glare brimming with frustration that most of the others seemed to interpret as fury. "I've looked over Galton's work, Ray," Rurik spoke up with some hesitation. "I can only think of one effect that hasn't been taken into account."

"Well?"

"We're dealing with iron atoms here, much larger than neutrons, and with electron clouds at—relatively—great distances. As the atoms approach Firefly, the first things to be swallowed will be an electron or two, which will leave the atom with a net positive charge. Since the black hole is also positive, the atom—the ion, now—will be deflected slightly before the nucleus gets to Firefly."

"And some of the shots that would otherwise have hit don't make it in," Carter growled. "Makes sense. Unfortunately. Is it worth switching the other two beams, do you think?"

"I doubt it. We'd gain a little, maybe, but most of that would be offset by the losses while the DeVegas are being altered."

"Doc, would it help to run the beams faster?" Rossetti asked. "If the time interval between ionization and contact was smaller, the atoms wouldn't be deflected as far."

Carter looked at Mahler and raised his eyebrows. "Possible?"

"Sorry. These DeVegas were specially designed to deliver high-particle currents, and for technical reasons we can't boost the velocities any higher than they are now." There was a moment of silence. Then Kapoor's soft voice broke into the others' thoughts. "Dr. Carter, are you going to switch back to a neutron beam?"

"Why? The iron atoms aren't doing any worse than the neutrons are and we'd just lose ten more minutes of beam during switchover."

"It seemed to me, sir, that if the black hole is absorbing one or two electrons from even those atoms which are deflected—"

Kapoor never got to finish his sentence. "My God!" Rurik exploded. "He's right, Ray. We've got to change that beam, fast."

"Right." Carter had caught Kapoor's drift at the same time Rurik had, and his heart was pounding violently in his ears. "Felix, get your men on that beam, now."

Mahler was already talking urgently into his intercom.

"I don't understand, Dr. Carter," Senator Chou murmured from his left.

Carter turned to face him. "The only thing that keeps Firefly in place is the electric field from the main plates, and for that to work Firefly has to have a heavy positive charge. Each extra electron that goes in cancels one of those charges. If the charge goes down to zero, we'll have no way of holding Firefly in the neutron beams."

"You couldn't recapture it?"

"Not in time. Possibly not at all."

Mahler looked up. "Okay, Ray, Beta's down again. Santos and Trumbell will have it running with neutrons in a few minutes."

"And I've just talked to the control room," Rossetti added. "Firefly's still holding positive charge, well within safety limits."

Rurik leaned back in his chair. "We were lucky," he muttered to no one in particular.

"Yes," Carter agreed. He took a deep breath and let it out slowly before continuing. "Gentlemen, we still have a crisis on our hands. We have got to find a way to get more mass into Firefly. Suggestions?"

There was a long silence. "I don't suppose it would help to enclose Firefly in degenerate matter of some kind," Rossetti said hesitantly.

Rurik shook his head. "We'd need better than neutron star density to make any headway—and even if we could make material like that we'd never get it near Firefly. The thing's just too hot."

Mahler looked up from a tablet he'd been writing on. "Whatever we're going to do, we have to do it fast," he announced quietly. "At the current rate of temperature increase, Firefly's radiation pressure will soon match the driving force behind the neutron beams. When that happens the DeVegas are, for all practical purposes, useless."

Carter had to force the words out. "How long?"

"Sixty hours. Maybe sixty-five."

Someone muttered a shocked obscenity. Carter felt his stomach trying to curl up and die. Sixty hours! His eyes swept the room of their own volition, as if looking for a way out, and finally came to rest on Kapoor's abnormally pale face. The Indian had been right to be so gloomy, Carter thought, feeling strangely light- headed. It had been sheer folly to suppose mankind could tame even a tiny black hole. They might as well have tried to hitch a tiger to a plow....

With a physical effort Carter shook the vertigo from his mind. He couldn't afford to go to pieces. "All right," he said. "You all know what that means. I want some ideas and some solutions. For starters"—he looked at Mahler—"I want the spare DeVega set up as close to the accelerator ring as possible." He raised a hand as the other started to object. "I know, at that distance it won't help much. But we need anything we can get, and it may at least buy us some time. Punch some holes in the shielding and collector sphere to let the beam through."

"Right." Mahler scribbled a note. "I'll get a crew on it right now." Sliding his chair back, the engineer launched himself through the door.

"I'm calling a recess," Carter said to the others. "We'll meet back here in an hour."

Carter remained in his chair until the others had left, staring at the table as he gently kneaded his temples with his fingertips.

"You look tired. You'd better get some sleep."

Carter looked up in surprise. "I thought you'd left with the others, Senator."

Chou shook his head, his eyes never leaving Carters face. "I meant what I said about sleep, Doctor."

"Can't afford the time." He smiled wanly. "Why the sudden solicitude? I thought you didn't like me."

"My likes or dislikes are of complete unimportance," Chou replied. "If anyone can come up with the solution we need, it will probably be you, and we can't afford to let your intellect break down from fatigue."

Even to himself, Carter's laugh sounded hollow. "Some intellect. I wasted several badly needed hours with the iron atom fiasco, and damn near lost our control of Firefly in the bargain. I tell you, Senator, if we're relying on me, we might as well quit now."

Chou was silent for a moment. "If we can't stop this, how long do we have?"

"Until the explosion? A year, probably. If our theory is right, that is; if it isn't I have no idea. Of course, Firefly will be far too hot to approach long before that."

"Dr. Carter... can we stop Firefly?"

Carter shook his head slowly. "I can't see any way to do it. No way at all. My God, Senator, what's going to happen to all those people?"

"We won't be able to evacuate them in time. Besides, where would they go? Ceres and Hestia can't absorb any excess population. Maybe we can tow the Space Colonies out of Earth orbit into the asteroid belt; they should be able to survive out there." Chou shook his head, his face a mirror of horror and pain. "But Earth has no chance."

"No."

Chou looked up. Carter avoided his eyes. The blame is not yours, Doctor," the Senator said. "We—mankind's leaders—made the final decision on Firefly. Ours is the responsibility. Not that laying blame helps any." He sighed. "Ironic, isn't it? For the past three centuries we have been continually worried about running out of energy, but now the final crisis arrives in the form of too much energy."

Something brushed the edge of Carters mind. "Say that last again, will you?"

"What? I just said our final crisis was too much energy, whereas in the past—"

"Too much. Too much." Suddenly the fatigue was gone, dislodged from his mind by a maelstrom of new thoughts and ideas. Fumbling out his intercom, he keyed for general 'cast. "This is Carter. All senior staff, report to conference immediately."

"Dr. Carter...?"

Carter glanced up and smiled slightly at the Senators uneasy expression. "Don't worry, I haven't crossed my circuits; at least, not yet. You just reminded me that there are two sides to this problem and we've been ignoring one of them. Excuse me now, I have to think."

He was still scribbling on a pad when the others arrived and took their places. "All right," he said. "First of all, has anyone else come up with anything?"

No one spoke, but Carter could feel the drop in tension throughout the room as they realized there was a hidden promise in his question. "I don't guarantee this," he warned them, "but see what you think. So far we've been concentrating on getting more mass into Firefly. Maybe we can hit the problem from the other direction; namely, to decrease the density of the particle cloud that's keeping the neutrons out in the first place."

"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.