Gregory Benford Read online

  The intruder was about 50 Astronomical Units out, somewhat beyond the range of Pluto’s orbit. It was coming in at about a thirty-degree angle with respect to the plane the planets orbited in, the ecliptic. As Channing put it, “The thing’s pretty close—and closing fast.”

  They all looked at each other. Unspoken was their growing sense of strangeness.

  Now it was his turn. Benjamin began writing on the blackboard. Style mattered in bringing forth an argument, and he set the stage with numbers, bringing out the underlying contradiction.

  The belt of iceteroids just beyond Pluto had been first imagined by Gerard Kuiper at the University of Chicago in the 1950s. The intruder could be hitting those. Little was known of them, despite their being much closer than the larger swarm in the Oort cloud farther out.

  Benjamin drew out the point carefully. Models of the Kuiper Belt showed that the icy chunks were on average an Astronomical Unit apart—quite thinly spread. Typically they were a kilometer or two in size, about the same size as the apparent core dimension of the intruder, as seen in visible light.

  “A coincidence, of course, their being about the same size,” Benjamin said. “They can’t be the same kind of thing. Point is, the odds of hitting an iceteroid in all that space are tiny.” He followed with two viewgraphs giving the statistical argument, thick lines of calculations.

  “If it’s randomly hitting obstructions, then even at its colossal speed”—he paused to emphasize—“nearly a hundredth the speed of light!—then it would not strike one in a million years.”

  Gasps. They saw the point; a bullet fired into a light snowstorm had a far better chance of hitting a snowflake.

  Kingsley looked up from scribbling in his leatherbound notebook, its ornate binding his only affectation. “In fact, it should take this intruder at least a day to fly from one iceteroid to the next—at the speed Amy worked out. Something is quite seriously wrong here.”

  “I believe there are two ways out”—Benjamin went on almost as if Kingsley had not spoken—“if we want to save our idea that the thing is striking iceteroids and processing their mass into highly energetic stuff. First, as Channing pointed out—”

  “It’s processing their mass in stages, holding some to chew later,” she said for herself. “That would mean it can somehow save pieces of ice.”

  “Can’t imagine how,” Kingsley said laconically, looking down at his notes as if to avoid any conflict with her.

  Amy said brusquely, “Me, either. But I think I see your second idea, Ben. It’s not hitting these iceteroids at random. It’s aiming for the next one, using the velocity change it got from consuming the last one.”

  Benjamin nodded. There it was, a clear leap into the unknown. Much better to have Amy make the jump. A genuinely crazy idea, however much he had tried to couch it in terms of times and distances and statistical probabilities.

  “The ‘starship hypothesis’ again,” Kingsley said incredulously. “Keeps popping up, despite its absurdity.” This time he looked Benjamin full in the eye.

  “How so?” Benjamin asked with a real effort at keeping his tone polite, though he knew what was coming.

  “Calculate the flux of gamma radiation from the source. It’s very bright. Any starship passengers near that flare would be crisped.”

  “I thought about that,” Benjamin said, trying not to sound defensive, though of course that was just what he was. “As yet I have no answer—”

  “Except that the ship need not be crewed at all,” Channing put in smoothly, as though they had planned it this way. “Machines could tolerate gamma rays pretty well, if necessary.”

  Benjamin had not thought of this possibility. He smiled at her in silent thanks.

  Kingsley waved this away with a quick flap of his wrist. “I’d hate to try to keep electronics alive in such an environment. Nothing could withstand it.”

  “I didn’t use the term ‘starship.’ You did,” Benjamin said hotly. “And—”

  “I used it,” Channing put in, grinning, “but only as a metaphor.”

  Kingsley looked irked but said levelly, “Metaphor for what?”

  “Something unexpected, maybe obeying rules we haven’t thought of yet,” she said brightly. Benjamin could see the price she was paying for this in the darkening rims around her eyes.

  “Or no rules at all,” Kingsley said curtly.

  “How else can you explain that it is hitting objects far more often than it should?” Benjamin pressed him.

  “I look for another idea,” Kingsley shot back, “one with some rules to bound it.”

  Benjamin saw suddenly a chink in the man’s armor. Just when you thought you were winning the rat race, along came faster rats. Kingsley was unaccustomed to having his back to the wall in an argument. Perhaps his reputation kept him out of such scrapes now. Well, not here. “We don’t need rules, we need ideas.”

  “Either we have a discussion hinged at one end by plausibility, or else—”

  “Now, don’t get—”

  “Look,” Amy said loudly. The two men stopped, both open-mouthed, and looked at her as if remembering where and who they were. Amy pretended not to notice and went on in the measured tones of one aware of being surrounded by her superiors, “The point is, this thing is decelerating at a rate we can’t account for. Maybe it’s ejecting its own mass to slow itself. Maybe it’s a runaway neutron star—like that one Channing was talking about the other day, remember? The Mouse?” She looked around the seminar table; her long hair was pulled back and knotted, so she seemed more austere. “That could act pretty peculiarly. So let’s not get pushed out of shape by this mystery, okay?”

  Benjamin nodded, rueful that he had let the discussion take so personal a turn. They were all under a lot of pressure, but that did not justify rubbing rhetorical salt into old wounds.

  The talk swerved to other aspects of the problem. Data was pouring in from ground observers and space-based alike. The astronomical data streams on the Internet were thick with discussions and endless inquiries.

  Already, theorists were demanding that they publish their findings on the Internet. Worse, some had written papers explaining various pieces of the puzzle, posting their hasty work to the high-display Net showcases. There were advantages to “publishing” electronically: considerable speed, nailing down credit for an idea, while not waiting for the reviewing process. Indeed, the more hot-topic areas of science now resembled a shouting mob more than a scholarly discourse, thanks to instant democratic communication.

  They were all besieged by colleagues through e-mail. Others had simply buttonholed them in the Center corridors. Everyone local was working on sifting the data stream, but few knew what was up, overall, because there were so many pieces of the puzzle to assemble. And the Gang of Four arrangement had not facilitated communication, either, Benjamin had to admit, though it was efficient at giving ideas a thorough thrashing over before they escaped into the larger community. In a media-saturated culture, cloisters of reflection were invaluable.

  “So what’ll we do?” Amy asked the older and presumably wiser heads.

  “Get out a paper?” Channing asked wanly. Plainly she had no desire to write it. The hunt was all for her, not talking about it afterward.

  “I think not,” Victoria Martinez said, jaw set firmly.

  Benjamin had nearly forgotten that she was in the room. She sat at the far end of the table and had taken many notes, but she had added nothing until now. He was again embarrassed that she had seen the cut and thrust between him and Kingsley.

  “Definitely not,” she said, carefully looking at each of them in turn. “This is an enormously energetic object, behaving strangely, and if it continues at its present velocity, it will reach the inner solar system within a month. Am I correct?”

  “Yes,” Kingsley answered, “though remember, it is decelerating.”

  Benjamin became aware of a tension between Victoria and Kingsley, whose mouth had compressed into a thin line. The
intruder’s incredible velocity had moved it the distance between the Earth and the sun in about half a day. They all knew this, but the consensus among the Gang of Four had been that worrying about future effects was pointless until they got a good handle on what the thing was. Plainly Victoria did not feel the same.

  “One point you’ve skipped over, I believe, is that it appears to be headed straight inward.”

  Amy said, “Well, yes, there’s no sign of sideways movement yet. But at these velocities it would be hard to detect right away.”

  “But I take your drift,” Kingsley said. “A possible danger.”

  Benjamin blinked. He had not thought along these lines in detail. “Of what? Chances of it coming near the Earth—”

  “Are impossible to estimate, since it changes velocity with every encounter—correct?” Victoria Martinez said incisively.

  Amy answered quietly, “Well, maybe. There’s a little Doppler shift in the lines after every collision. If the gamma-ray bursts do represent collisions.”

  “Let’s assume they do, until we have some better idea,” Martinez said. “How else can it find its next iceteroid, unless it changes velocity?”

  “Quite true,” Kingsley said in his pontifical drawl, “but not yet cause for alarm.”

  “I agree, Dr. Dart, that it is hard to accept some of the ideas I’ve heard bandied about the room this last hour. But we have nothing more in the pot, and it’s time to cook.”

  This metaphor went past Benjamin. “‘Cook’?”

  “I have to get back to a lot of people about this. Word gets around. The NSF and NASA both fund this Center, and they do like to be kept in the loop. I’ve been shielding you folks while you worked, but I have to start speaking for you now. Unless you’d rather do it yourself?”

  “Oh no,” Benjamin said, knowing this was what she wanted. “You do it.”

  “Good. Then I’ll be answering a lot of phone calls I’ve been stalling. And you four start writing up a statement.”

  “Statement?” Benjamin felt uncomfortably that he was asking stupid questions whose answers were obvious to the others.

  “For the media,” Kingsley said offhandedly. “Quite so.”

  Martinez said, “At its present speed, it could reach us within a month.”

  “I suggest we not emphasize that aspect,” Benjamin said, choosing his diction so that it echoed Kingsley’s precision. “Especially since it is not headed for us at all.”

  “Oh?” Martinez looked surprised.

  He realized he had not shown his trajectory plots around yet. “It’s curving in and downward, heading at an angle to the ecliptic plane. I can’t pick out any destination. It will pass through the solar system and leave, as it is unbound. It is moving very fast.”

  2

  She could remember drinking coffee to stay awake and keep working; now she needed it to wake up at all.

  Running mostly on caffeine, Channing puttered around in her home office, immersed in cyberspatial bliss: sleek modern desk the size of a tennis court; ergonomic chair that was better than a shiatsu massage—and cheaper; picture window on the Pacific (today looking anything but); overstuffed leather chaise where she spent far too much time recouping; big tunnel skylight leading up to a turquoise tropical sky.

  Self-respect demanded that she not work in pajamas. That left a lot of room in a vast sartorial wasteland, from T-shirts and khaki to turtlenecks down to jeans, running shorts, and tanks. All those were off the menu if she was going to do a visual conference with anybody, in which case she needed at least a decent frilly blouse, say, or even a full dress suit—top only needed, of course, since her camera had a carefully controlled field of view. She had heard of the new image managers that touched up your face as you spoke, smoothing out lines and wrinkles and even black eyes if you wanted. To order up one on the Net would be quick, easy to install…and the vanity of it would pester her inner schoolmarm for weeks. Nope, let ’em see the truth. That’s what science is about, right? Why not treat scientists the same way?

  Today something clingy, island-soft, and cool. In blue, it cheered her.

  She had liked working at home the first month, despised it thereafter. After all, “I work at home” carried the delicate hint that you were in fact just about unemployed, or downsized out of the action, at the fringe of the Real World.

  So she tried to be systematic. No distractions, that was the trouble. After years working at the Center, it was hard to get by with no coffee break, water cooler chat, endless meetings with clandestine notes passed ridiculing the speaker, business lunches, the sheer simple humanity of primates making a go of it together.

  Work at home and you could never quite leave it. Slump onto the couch at nine at night when Benjamin was on a trip, all ready to kick back and veg out like any deserving, stressed adult…and down there at the end of the hall lurked the reproachful glimmer of the desk lamp. It was hard to walk down there and turn it off and walk back to a sitcom without checking the e-mail or looking at tomorrow’s calendar, especially since its first screen was the latest selection from Studmuffins of Science.

  She suspected her social skills, honed in the labyrinths of NASA and the NSF, were atrophying. So she did the next best thing, first off in the morning: answer vital e-mail, delete most without answering, and look over her notes. This kept her in a sort of abstract cyber-society.

  The more traditional Net temptations no longer carried their zest. No point in doing an Ego Surf on her name; it showed up only on historical mesh sites now. Her Elvis Year, the time of popularity, was now long gone, back when shuttle missions made you a pseudo-celeb among some of the Internet tribes.

  Since then she had been happier, more satisfied, steadily getting more obscure. Funny thing about contentment, some years just got lost. Seen it, done it, can’t recall most of it.

  Through those dimly recalled years, she had been happier with Benjamin than she probably had any right to be, and now that it was nearly over, to review it all seemed pointless. There were parts of the play she would have rewritten, especially the dialogue. Somehow, despite all her theories and ambitions, she still regretted not having children. The career had seemed more important, and maybe it still was to her, but regrets don’t listen to theories. There were plenty of roads not taken and no maps.

  She finished her e-mail and looked over the work she was doing on spectral analysis. The data pouring into the Center needed careful attention and she had been pitching in, giving the multitude of optical line profiles a thorough scrutiny. She popped the most puzzling ones up on her big screen and ran a whole suite of numerical codes, sniffing around. This took two hours and much intricate tedium. Still, the repetition was soothing, somehow: Zen Astrophysics. She was feeling the slow ebbing fatigue she knew so well when a clear result finally surfaced.

  Three optical lines emitted from the intruder came out looking decidedly odd: each was split into two equal peaks. These were not the Doppler shifts they had spotted earlier. They were much smaller, imposed on the Doppler peaks themselves.

  There are very few ways an atom can emit radiation at two very closely spaced intervals. The most common occurs if the atom is immersed in a magnetic field. Then its energy would depend upon whether its electrons aligned with the field or against it.

  These three splittings she had pulled out of the noise, imposing several different observations from several different ’scopes. And they led to a surprising result: the magnetic field values needed to explain these up-and-down shifts were huge, several thousand times the Earth’s field.

  “Good grief,” she muttered to herself, instantly suspicious.

  Most amazing results were mistakes. She burned another hour making sure this one was not.

  Then she sat and looked at the tiny twin peaks and liked knowing that Benjamin would be thrilled by it. The give-and-take with the others at the Center, especially the Gang of Four, was great fun, but his reaction was still the crucial pleasure for her.

  A
bruptly she remembered her first experience of astronomy, as a little girl. Camping out, she had awakened after midnight, faceup. There they were. Even above the summer’s heat, the stars were immensely cold. They glittered in the wheeling crystal dark, at the end of a span she could not imagine without dread. High, hard, hanging above her in a tunnel longer than humans could comprehend.

  When she had first felt them that way, she had dug her fingers into the soft warm grass and held on—above a yawning abyss she felt in her body as both wonderful and terrible. Impossible to ignore.

  She had not realized until years later how that moment had shaped her.

  She took a break, stretched, felt the tiredness fall away a little, and glanced out a window. From the abstract astrophysical to the humid neighborhood, all in one lungful of moist air.

  It was so easy to forget that she dwelled in what most people regarded as the nearest Earthly parallel to heaven. The volcanic soil was rich, lying beneath ample rains and sun. Irrigated paddies gave taro’s starchy roots, which made poi when mashed. There were ginger and berries, mango, guava, Java plum, and of course bananas. The candlenut tree gave oily brown nuts, which, strung together, burned to give hours of flickering light. The sheer usefulness of candlenuts to humans seemed like an argument from design for a God-made world, customized to smart primates. But it was also a paradise with mosquitoes and lava flows—counterarguments. Well, she could settle the argument about God and paradise within a year. Probably less, the doctors said in their cagey way.

  Her fatigue evaporated. The man she had been thinking of now for days was coming up the path.

  There were Englishmen and then there were quintessential Englishmen, the types everyone expected to meet and never did. All had their points, in her experience, except maybe the ones whose accents were pasted on and covered over sentiments as soft as sidewalk. There was the jolly fellow who had many friends who would surely stand him a drink, all unfortunately out of the room just now. There was the erudite type who knew more about Shakespeare than anybody and so never went to see anything modern. He was better than the lit’ry one who kept rubbing his foot against your calf under the table while he wondered very earnestly what you did think of that recent novel, really? She liked the slim, athletic engineery types who were modest about their feats and never spoke of them but could fix a balky engine or conjugate a French verb, often simultaneously. They were even good in bed, though she got tired of the modesty because in the end it was fake, a social mannerism, a class signature.