by Timothy Zahn
He continued before the murmurings had quite died down. "The object is traveling a hair below lightspeed, at about point nine nine nine cee, using an extremely hot fusion drive of some kind and what seems to be an electromagnetic ramscoop arrangement. He's about eight light-days out—under fourteen hundred A.U.—and while we haven't got his exact course down yet, he'll definitely pass through the System."
" 'Through,' General?" asked Evelyn Woodcock, chief assistant to the Executor. "It's not going to stop here?"
"No, his drive's still pointing backwards," Carey told her. "Decelerating to a stop now would take hundreds of gees."
From their expressions it was clear they weren't sure whether to be relieved or insulted by the Intruder's disinterest. "Then why is it coming here?" Assembly-Prime Wu-sin asked.
"Reconnaissance, possibly, though that's unlikely. He's coming in at a steep angle to the ecliptic—a poor vector if he wants to see much of the System. He could also be trying for a slight course correction by passing close to the sun; we'll know that better when we get more accurate readings on him. It's even possible the Intruder doesn't yet know we're here. At the speed he's making, the sun's light is blue-shifted into the ultraviolet, and he might not have the proper instruments to detect it."
"Unlikely," Dr. Louis Du Bellay of the Chiron Institute murmured. "I would guess they've done this before."
"Agreed, Doctor," Carey nodded. "It's a very remote possibility. Well. The Intruder, then, is not likely to be of great danger to us, provided we keep local traffic out of his way. By the same token, he's not likely to advance our store of knowledge significantly, either. With one exception: we now know we're not alone in the universe. You'll appreciate, I'm sure, the importance of not springing this revelation on the System and colonies without some careful thought on the part of all of us. Thank you for coming here; we'll keep you informed."
Carey stepped from the lectern and headed toward the door as his audience came alive with a buzz of intense conversation. As Carey passed him, Dr. Du Bellay rose and fell into step. "Would you mind if I tagged along with you back to the Situation Room, General?" he asked. "I'd like to keep close tabs on this event."
Carey nodded. "I rather expected you'd want to. I've already had you cleared for entry." He raised his hand warningly as the Security man reached for the spy-seal control. "No talking about this, Doctor, until we're past the inner security shield."
It was only a short walk to the central section of Peacekeeper Headquarters, and the two men filled the time by discussing Du Bellay's latest trip to the ancient ruins at Van Maanen's Star. "I heard about that," Carey said. "I understand it was your first solo tachship run."
"Yes. The Directorate at Chiron's been encouraging everyone to learn to fly—it's cheaper than always having to hire a pilot along with a tachship. Fortunately, they haven't yet suggested I do all my own digging as well."
Carey chuckled. "That's what students are for. Are those ruins really as extensive as people say?"
"Even more so. We've barely scratched the surface, and there's at least one more civilization under the one we're working on."
They passed the security shield to the clickings of invisible security systems, and the topic abruptly changed. "How in blazes did a tachship stumble across something moving that fast?" Du Bellay asked.
"Pure dumb luck," Carey said. "A merchantman coming in from Alpha Centauri had dropped back into normal space to do a navigational check. They'd just finished when this thing went roaring past."
"They're lucky they weren't fried by the ramscoop fields," Du Bellay commented.
"They damn near were. A few million kilometers over and they probably would have been. Anyway, they recovered from the shock and got a preliminary reading on his course. Then they jumped ahead the shortest distance they could and waited the sixteen minutes it took the Intruder to catch up. They got another decimal in his course, confirmed he was heading toward Sol, and hightailed it here with the news."
"Hmm. Ironic, isn't it, that the great search for intelligent life should be ended by a puddle-jumping business whip whose navigator didn't trust his own computer. Well, what's next?"
"We've sent out a dozen tachships, strung along the Intruder's route, to get better data. They should be reporting in soon."
The Peacekeeper Situation Room was a vast maze of vision screens, holotanks, and computer terminals, presided over by a resident corps of officers and technicians. Halfway across the room was the main screen, currently showing a map of the entire solar system. From its lower right-hand corner a dotted red line speared into the inner system.
A young captain glanced up from a paper-strewn table as they approached. "Ah, General, he greeted Carey. "Just in time, sir: Chaser data's coming in."
"Let's see what you've got, Mahendra."
Mahendra handed him a computer-printed page. Carey scanned it, aware that Du Bailey was reading over his shoulder.
The Intruder was big. Compensating for relativistic effects and the difficulty of taking data at such speeds, the computer judged the alien craft at well over fifteen hundred meters long, two hundred meters in diameter, and massing near the two-hundred-million-ton mark. Its cone-shaped ramscoop fields spread out hundreds of kilometers in front of it. The drive spectrum showed mainly helium, but with a surprisingly high percentage of other elements.
Behind him, Du Bellay whistled softly. "Talk about your basic Juggernaut! Where'd it come from?"
"We've backtracked him to the 1228 Circini system," Mahendra said, referring to one of his sheets. "He didn't originate there, though—it's a dead system. We're trying to track him further back."
Carey looked up at the main screen. "Why isn't the Intruder's course projected beyond Sol?"
Mahendra frowned. "I don't know, sir." He swung a keyboard over and typed something. "The projection stopped when the course intersected the sun," he reported, frowning a bit harder.
"What?" Du Bellay said.
"Show us the inner system," Carey ordered.
Mahendra punched a key and the screen changed, now showing only out to Mars. Sure enough, the dotted line intersected the edge of the dime-sized image of the sun. Without being told to, Mahendra jumped the scale again, and the sun filled the screen.
Carey squinted at it. "Almost misses. How dense is the stuff he'll hit?"
"The computer says about ten to the minus seventh grams per cc. Not much by Earth standards, but that's almost a hundred trillion times anything in the interstellar medium. And he'll pass through several thousand kilometers of it."
"Like hell he will," Carey winced. "He'll burn to a crisp long before that. I was right after all, Doctor—he hasn't noticed the solar system's in his path."
He glanced at Du Bellay, then paused for a longer look. The archaeologist was frowning into space. "Doctor?"
"Captain, does that console have DatRetNet capability?" Du Bellay asked. "Please look up data on that star you mentioned—1228 Circini. Cross-reference with unusual stellar activity."
Mahendra nodded and turned to the console. "Something wrong?" Carey asked Du Bellay. The other's expression worried him.
"I don't know. I seem to remember hearing about that star a few years ago...." He trailed off.
"Got it, Doctor," Mahendra spoke up.
Both Du Bellay and Carey leaned over to look at the console screen. "I was right," Du Bellay said in a graveyard voice, pointing at the third paragraph.
" 'Planetary studies indicate a giant solar flare occurred approximately one hundred years ago, causing extensive melting patterns as far out as one point eight A.U.,' " Carey read aloud. " 'Such behavior in a red dwarf is unexplainable by current theory.' I don't see the connec—" He broke off in mid-sentence.
Du Bellay nodded grimly. "1228 Circini is ninety-six light-years away. It's too close to be coincidence."
"Are you suggesting the Intruder deliberately rammed 1228 Circini? That's crazy!"
Du Bellay merely nodded at the main screen.
Carey gazed up at the dotted line for a long minute. Then he tapped Mahendra's shoulder. "Captain, get me Executor Nordli. Priority Urgent-One."
—
Orofan woke to hear the last wisp of sound from his intercommunicator. He reached for the control, noting with some surprise that the shading of the muted wall light indicated half past cin—he'd been asleep less than an aarn.
"Yes?"
It was Pliij. "Shipmaster, we have a problem. You'd best come up immediately."
Was something wrong with his ship? "I'll be right there."
Pliij was not alone when Orofan arrived on the bridge. Lassarr was also there. "Greetings, Voyagemaster," Orofan said, giving the required salute even as his eyes darted around the room. No problem was registering on any of the displays.
"The trouble is not with the Dawnsent," Voyagemaster Lassarr said, interpreting Orofan's actions and expression with an ease the Shipmaster had never liked.
"Then what is it?"
"Here, Shipmaster." Pliij manipulated a control and an image, relativistically compensated, appeared on a screen. "This is the system we're approaching. Look closely here, and here, and here."
Tiny flecks of light, Orofan saw. The spectrometer read them as hot helium....
Orofan felt suddenly cold all over. Fusion-drive spacecraft! "The system is inhabited!" he hissed.
"You understand our dilemma," Lassarr said heavily.
Orofan understood, all right. The Dawnsent's scooping procedure would unavoidably set up massive shock waves in the star's surface layers, sending flares of energy and radiation outward....
"How is our fuel supply?" Lassarr asked.
Orofan knew, but let Pliij check anyway. "Down to point one-oh-four maximum," the Pilot said.
"We can't reach our new home with that," Lassarr murmured.
"Correction, Voyagemaster," Orofan said. "We can't reach it in the appointed time. But our normal scooping gives us sufficient fuel to finish the voyage."
"At greatly reduced speed," Lassarr pointed out. "How soon could we arrive?"
There was silence as Pliij did the calculation. "Several lifetimes," he said at last. "Five, perhaps six."
"So," Lassarr said, short tentacles set grimly. "I'm afraid that settles the matter."
"Settles it how?" Orofan asked suspiciously.
"It's unfortunate, but we cannot risk such a delay. The sleep tanks weren't designed to last that long."
"You're saying, then, that we continue our present course? Despite what that'll do to life in this system?"
Lassarr frowned at him. "I remind you, Shipmaster, that we carry a million of our fellow Sk'cee—"
"Whose lives are worth more than the billions of beings who may inhabit that system?"
"You have a curious philosophy, Shipmaster; a philosophy, I might add, that could be misunderstood. What would the ancestors say if you came among them after deliberately allowing a million Sk'cee to perish helplessly? What would those million themselves say?"
"What would they say," Orofan countered softly, "if they knew we'd bought their lives at such a cost to others? Is there honor in that, Voyagemaster?"
"Honor lies in the performance of one's duty. Mine is to deliver the colonists safely to their new world."
"I'm aware of that. But surely there's a higher responsibility here. And we don't know the sleep tanks won't survive the longer journey."
Lassarr considered him silently. "It's clear you feel strongly about this," he said finally. "I propose a compromise. You have one aarn to offer a reasonable alternative. If you can't we'll carry out our fuel scoop on schedule." He turned and strode out.
Pliij looked at Orofan. "What now?"
The Shipmaster sank into a seat, thinking furiously. "Get me all the information we have on this region of space. Our own sensor work, Farseer charts and data—everything. There has to be another way."
—
The group sitting around the table was small, highly select, and very powerful. And, Carey thought as he finished his explanation, considerably shaken. Executor Nordli took over even as the general was sitting down. "Obviously, our first order of business is to find out why our visitor is planning to dive into the sun. Suggestions?"
"Mr. Executor, I believe I have a logical explanation," an older man sitting next to Du Bellay spoke up. Dr. Horan Roth, Carey remembered: chief astrophysicist at the Chiron Institute.
"Go ahead, Dr. Roth," Nordli said.
Roth steepled his fingers. "The speed of a ramjet is limited not by relativity, but by friction with the interstellar medium. The mathematics are trivial; the bottom line is that the limiting speed is just that of the ship's exhaust. Now, if you use a magnetic scoop to take in hydrogen, fuse it to helium, and use the energy liberated to send this helium out your exhaust, it turns out that your velocity is only twelve percent lightspeed."
"But the Intruder's moving considerably faster than that," Assembly-Prime Wu-sin objected.
"Exactly," Roth nodded. "They're apparently using an after-accelerator of some sort to boost their exhaust speed. But this takes energy, requiring extra fuel."
"I see," Nordli rumbled. "They have to carry extra hydrogen which can't be replaced in the interstellar medium. So they periodically dive into a star to replenish their tanks?"
"It would seem so."
"Dr. Du Bellay, you're an expert on alien cultures, correct?" Nordli asked.
"To some extent, sir," Du Bellay said, "bearing in mind we've so far studied only dead civilizations, and only a handful of those."
"Yes. In your opinion, what are the chances of communicating with these aliens? And what are the chances that would make any difference in their actions?"
Du Bellay frowned. "I'm afraid the answer to both questions is very poor," he said slowly. "It's true that various scientists have developed so-called 'first-contact primers' in case we ever came across a living intelligent species. But it's also true that teaching any of our language to an alien would take considerable time, and we haven't got that time. No ship ever built could match speeds with the Intruder, so we would have to give everything to them in short, high-density data bursts. And even assuming they were equipped to receive whichever wavelengths we use, they have only seven or eight hours—in their time frame—to decipher it."
"I have to concur with Dr. Du Bellay," Carey spoke up. "As a matter of fact, we've already sent out a series of tachships to try precisely what he suggested, but we don't expect anything to come of it."
"Perhaps we could signal our existence some other way," Evelyn Woodcock, Nordli's assistant, suggested. "Say, a fusion drive pointed at them, blinking off and on. They couldn't miss that."
"And then what?" Carey asked.
"Why—surely they'd change course."
"With their own mission at stake? If it's a colony ship of some kind, its supplies are likely very tightly figured. If they change course, they may die. At the speed they're making we sure as hell can't offer to refuel them."
"There's an even more disturbing possibility," Nordli said quietly. "This refueling technique may be deliberately designed to sterilize the system for future colonization."
"I think it's unfair to ascribe motives like that to them without proof," Du Bellay said. The words, Carey judged, were more reflex than true objection—the archaeologist looked as uneasy as everyone else.
"No?" Nordli shrugged. "It doesn't really matter. What matters is that the Intruder is threatening us with massive destruction. We must stop him."
Wu-sin stirred. "Executor Nordli, you're proposing what amounts to an act of war against another intelligent species. A decision of that magnitude must be approved by the full Solar Assembly at least; ideally by all the colonies as well."
"There's no time to consult the colonies," Nordli said. "As to the Assembly... you have two hours to get their approval."
"And if I can't?"
"I'll go ahead without it."
Wu-sin nodded grimly. "I needed to know where you stan
d. I'll get their approval." He rose, bowed, and left the room.
Nordli turned to Carey. "General, how do we proceed?"
Carey let his eyes sweep the others' faces as he thought. They were all on Nordli's side, he saw: Du Bellay, like himself, only because there was no other choice. How many lives were they planning to snuff out?—innocent lives, perhaps, who may not realize what they were doing? "The trouble, Mr. Executor, is that the Peacekeeper forces really aren't set up for this kind of threat."
"You've got nuclear missiles, don't you? And ships to deliver them?"
"There are two problems. First, hitting the Intruder would be extremely difficult. A shot from the side would probably miss, alerting them as to our intentions. A head-on shot would hit, all right, but the extremely high magnetic fields it would have to penetrate would almost certainly incapacitate any missile we've got. And second, there's no guarantee even a direct hit would do any good. Just because they don't have FTL drives doesn't mean they're primitives—only that their technology developed along different lines. And don't forget, that ship is designed to bore through the edge of a star at nearly lightspeed."
"There's one further problem," Dr. Roth spoke up. "Disabling or even disintegrating it at this point wouldn't help us any. The fragments would still hit the sun, with the same consequences."
There was a moment of silence. "Then we have to stop or deflect it." Evelyn suggested. "We have to put something massive in its path."
Nordli looked at Carey. "General?"
Carey was doing a quick calculation in his head. "Yes, either would work. Slowing it even slightly would sent it through a less dense region of the photosphere. Assuming, of course, that he stays with his present course."
"What can we put in his path?" Nordli asked. "Could we tow an asteroid out there?"
Carey shook his head. "Impossible. As I pointed out, he's far off the ecliptic plane. Moving an asteroid there would take months." Even as he spoke he was mentally checking off possibilities. Tachships were far too small to be useful, and the only heavy Peacekeeper ships in the System were too far away from the Intruder's path. "The only chance I can see," he said slowly, "is if there's a big private or commercial ship close enough to intercept him a good distance from the sun. But we don't have authority to requisition nonmilitary spacecraft."