Eater

by Gregory Benford

  “Channing, how wonderful to see you,” Kingsley said smoothly.

  He looked into her face with a worried frown, much as everyone did these days, as if they could read the state of her health there. Well, maybe they could; she was past the stage of trying to hide behind cosmetics. She knew that her skin was yellow and papery, her eyes rimmed with a dark under-layer, her once strong arms thin and showing swelling at the joints. It no longer even bothered her that people glanced at her out of the corner of their eyes, not wanting to stare but still drawn to hints of the eternal mystery—of what her mother called “passing,” as if there were a clear destination firmly in mind.

  “Thought I’d come in, see what all the excitement’s about.”

  “Is there much?” Kingsley said to Benjamin with deceptive lightness. “Have you made any announcement?”

  “Oh no, much too soon for that,” Benjamin said quickly.

  “Don’t want to just announce a mystery,” Amy put in.

  “But it’s all over the IAU Notices,” Kingsley said.

  This was the global notification system of the International Astronomical Union, used to focus workers on the newest comet or supernova or pulsar of interest. “Sure, but we’ve got to be cautious,” Benjamin said. “If this is a new class of object—”

  “Then you should enlist as many people and observing windows as possible,” Kingsley finished for him.

  Channing smiled, remembering. Kingsley had the annoying pattern of quickly disagreeing with you and often being right, plus the even worse property of agreeing with you and getting there first.

  Benjamin pursed his lips and plowed on. “I think the big issue is how this thing can repeat.”

  Kingsley said carefully, “I must admit, when I saw your Notices piece, I thought it most likely an error.”

  Amy said flatly, “It’s not an error, I can tell you that.”

  “I’m quite relieved to hear it.” Channing noted that with this phrase Kingsley was not actually agreeing with Amy, only reacting, but his choice of words avoided rankling her.

  “Look at it this way,” Benjamin put in. “At the very least, this object throws into doubt the standard picture of gamma-ray bursters.”

  Kingsley’s lips drew into a thin, skeptical line. “With many thousands observed, one exception does not disprove the model.”

  Since he had taken a major hand in building up the conventional view of gamma-ray bursters, this was predictable, Channing felt. She said amiably, “Similar appearance does not mean similar cause.”

  Kingsley nodded but Amy said, “Shouldn’t we follow Occam’s razor—prefer the simplest explanation? Then this is an odd kind of burster, but one in our galaxy.”

  Benjamin said, “Sure, but don’t throw out data just because it makes your job harder. We don’t understand the visible light data, either.”

  This led to a long discussion of the mysterious Doppler shifts. Channing had come up today mainly to see this data, and it was strange indeed. “It’s as though some of the thing’s coming toward us, some away. A rotating disk? We’d get the red shifts from the receding edge, blue shifts from the approaching one.”

  They all looked at her. “Good idea,” Benjamin said happily, winking and grinning. She could see that they were surprised in two ways—by the proposal itself, and because she had made it. She had come into astronomy as an observing astronaut, doing yeoman labor in the last stages of the space shuttle era, then doing dutiful time on the space station. The more academically based astronomers regarded these as rather showy, unserious pursuits. She had never risen very far here at the Center and had always wondered if that bias held her back. In the slightly startled expressions of Dart and Amy—but not, bless him, Benjamin—she saw confirmation.

  Kingsley said incisively, “I rather like that.”

  “But a disk?” Amy frowned doubtfully. “I’d say these are kinda large, but I’ll have to check…”

  “Good,” Kingsley said quickly. “At the moment we have no other hypothesis to test. I wish we did.”

  Channing was not the only one to notice that his use of we included Kingsley in the team. Benjamin’s eyes narrowed in a way she understood and he said, “Just wait. Theorists will jump on this like it was candy.”

  “They can theorize all they like,” Amy said. “We have all the data.”

  “Which we should make quick use of,” Kingsley said. “Let’s do some preliminary calculations, shall we?”

  Channing went with them to a seminar room and they reviewed the data. Some fresh observations came in over the satellite links as they worked, providing fresh fodder. She kept up with the discussions, but to her this branch of astrophysics was like a French Impressionist painting of a cow: suggestive, artful maybe, but some things never looked quite right and it was in the end not a reliable source of nourishing milk. Plus, she was woefully out of date on current theory. Still she found pleasure in watching Benjamin and Kingsley spar, using quickly jotted equations as weapons. Amy joined in, too, her tone a bit less canny and insidious, but holding her own.

  Kingsley jabbed verbally, challenging others’ ideas while seeming at first to be going along with them, inserting doubt slyly as he carried the discussion forward, ferret-eyed in his intensity. Just as decades before, he saw this as a delightful game played with chalk and sliding tones of voice.

  Channing found her attention drifting. Looking back, she could remember liking contests like this from decades past. Benjamin would always see Kingsley as a rival; that was set in his mind like a fossil print of their first meeting. Benjamin was a perfectly respectable theorist, but not in Kingsley’s class. That was simply a fact, but she knew quite well that Benjamin would never fully accept it. After all, who did not need a little illusion to get through life?

  Having bested Kingsley in a colloquium encounter set their relationship, as far as Benjamin was concerned. Never mind that Kingsley had done better work on bigger problems, and on top of it displayed remarkable skills in the political circus that science had become. She could barely recall that incident, but knew that it burned in Benjamin’s mind whenever he crossed Kingsley’s path. Probably Kingsley had forgotten it entirely. This seemingly small difference was precisely why they seldom saw each other. Too bad, really, because she had always found Kingsley more amusing than the usual run of academic astronomers. In their bull moose rivalries, men missed a lot.

  Would her own career at NASA have gone better, she mused, if she had been a man? Nobody in passing conversation would glance at your chest. You wouldn’t have to pretend to be “freshening up” to go to the goddamn john. Nobody cared if you didn’t remember their birthday. You could rationalize any behavior error with the all-purpose “Screw it.” In late-night jokes in a bar, you could really see something hilarious in punting a small dog, preferably a poodle. You didn’t give a rat’s ass whether anybody heeded your new haircut. Thank God, they never noticed if you’d lost or gained weight. Men had some things so easy! With the Other Side, flowers fixed anything. And as the years closed in, gray hair and wrinkles would add character. Hell, you could dine out on that alone. Lean over the bar, belch originally, and declaim about the old days when rocket boosters kicked you in the ass so hard you thought you had a prostate problem. And what the hell, you could always look forward to being a dirty old man.

  5

  He had expected the next day to be hours of more muddling along, with data trickling in and more idea-bashing with Kingsley and Amy. Instead, it proved decisive.

  The Very Large Baseline Interferometer reported in promptly, to everyone’s surprise. This network had grown from a few stations strewn around the world into an intricate system that now included radio telescopes orbiting farther away than the moon. Its “baseline” then made it effectively an instrument of enormous equivalent resolution, like having a dim eye of astronomical size. Getting a measurement quickly was pure luck. The distant SpaceWeb satellites had been looking in roughly the right portion of the sky, and B
enjamin’s request came in at the very end of a rather tedious job. Instrument tenders were human, too, and the mystery had caught their attention.

  The radio plume was thin, bright—and moving. Comparison with the earlier map showed definite changes in the filaments making up the thin image. Now they had two maps at different times show changing luminosity and position.

  “But these were taken only a day or so apart!” Kingsley jabbed at the differences between the maps with a bony finger.

  “So?” Benjamin gave him a slight smile.

  “Must be wrong.”

  Benjamin said, “No, it means this object is local—very local.”

  “You took the rate of change of these features and worked it into a distance estimate?” Amy asked.

  “Nothing moves faster than light—so I used that to set a bound. I came in early, had a chance to work through the numbers, and checked them by e-mail with the guys in Socorro.” The site of the now-outdated Very Large Array, Socorro, New Mexico, still had a practiced set of house theorists and observers, and Benjamin knew several of them well. “Jean Ellik, an old hand there, agrees: this thing can’t be much farther away than the Oort cloud.”

  “But it’s a radio object.”

  The Oort cloud was a huge spherical swarm of icy fragments orbiting beyond the orbit of Pluto. Objects there were frigid and unenergetic, exceptionally difficult to detect.

  “Something has found a way to light itself up, out there in the cold and dark,” Benjamin said happily. The look of consternation on Kingsley’s face was all he had been hoping for. He could not resist rubbing it in. “That added hypothesis you were asking for yesterday—here it is.”

  They quickly went to the head of the Center, Victoria Martinez, and got permission for added resources. “Get everybody on it,” she said intently. Martinez was a good astronomer who had been deflected into administration. Benjamin worried that he would drift along the same path, getting more disconnected from the science all the while. He was happy that she saw the implications immediately.

  They wrote a carefully phrased alert for the IAU Notices, asking for any and all observations of the object, in all frequency bands, because in Kingsley’s phrase, “inasmuch as this is a wholly unanticipated finding, no data is irrelevant.” “Let’s keep the media out of it for the moment,” Martinez said carefully, and they all agreed. Everyone remembered past embarrassments: mistaken reports of asteroids that might hit Earth, misidentified massive stars, spurious discovered planets around nearby stars.

  Kingsley was atypically silent. Apparently he had decided to “hang about” for a few days out of curiosity.

  Coaxed, Kingsley said, “Admittedly, all along I had thought that it would turn out to be a relativistic jet—yes, my favorite object. Indeed, one pointed very nearly straight at us. That would neatly explain its huge luminosity. Also, we would naturally see all the jet’s variations as occurring quickly, as they would be time-squeezed by relativity. Alas”—a touch of the theatrical here, holding a pen aloft like a phony sword—“it was not to be.”

  The gamma-ray signature had surfaced as crucial, and within hours Kingsley had a new idea.

  “Let us face facts, uncomfortable as they may be to conventional views,” he began to a small band in the seminar room, including Amy and Benjamin at the front. “It makes no sense if you suppose this is an object passing through the interstellar medium, a very thin gas. It would emit radiation, then, because it was striking objects in its way. A quick calculation”—he proceeded to produce this in quick, jabbing strokes on a blackboard as he spoke—“shows that one needs to expend only a trivial amount of power to overcome the friction of the interstellar hydrogen.” He dropped the chalk dramatically. “There is simply not enough matter nearby our solar system for it to run into.”

  He turned to the audience, which agreed. Or at least nodded; Kingsley’s reputation for incisive analysis was enough to silence the timid. Several were checking his numbers and did not look up.

  Channing had heard the news and was sitting in on the impromptu seminar that had developed spontaneously down the hall from Benjamin’s office. She saw her chance and stepped into the silence. “Okay, then we have to look elsewhere. It’s reasonably nearby, or else it couldn’t possibly be so luminous. So as savvy Kingsley implies, why is it luminous? Because it’s not gliding through, it’s accelerating.”

  Benjamin had not even known that Channing was in the room. He turned to look at her, a spark of uneasy pride at her speaking up so readily. Uneasy because Kingsley had a reputation for leaving questions hanging, only to knock them down when anyone ventured to take the next step without thinking it through. But this time the narrow, hatchet face showed only real puzzlement as it nodded. Kingsley put his hands behind his back, as if to disarm himself, and said slowly, “Perhaps, but why? There are no unusual signatures near it, nothing to be propelling it forward.”

  Benjamin got her drift. “Exactly. But what if it’s decelerating?”

  Kingsley shot back, “I just showed that the interstellar medium slows things very slowly. Nothing would naturally—”

  Channing broke in. “Suppose it’s not natural? What if it’s a starship?”

  Benjamin’s jaw dropped, but out of loyalty he tried to fill the skeptical silence that greeted her question. “P-passing near us?”

  To his amazement, she rose from her seat and stepped with fragile grace to the front, taking the chalk from Kingsley’s hand. Everyone in the room knew of her illness, but he sensed that her command of them came from the quality that had made her a successful astronaut, a presence he could never name but that he sensed every day. He felt a burst of pride for her and a smile split his face, telltale of a joy he had not felt quite this way for a very long time. Since the illness, in fact.

  This was a mere instant, for Channing did not pause to absorb the regard of the room. Quickly she did her own swift calculation. It all depended upon the source’s intrinsic luminosity. A bright source ten light-years away looked the same as one a light year away and a hundred times dimmer, so—she turned to the audience, neatly jotting L = P/R2, and said, “With P the ship’s power demand and R in light-years, we have—” More jotting. “How much does one need to ram a ship through the interstellar medium?”

  The crowd now filled the room to overflowing, Benjamin noticed, and from the packed faces came guesses: “The power level of a city?” and “No, nearer to all of North America.”

  She shook her head. “Try the whole planet.”

  A gasp of surprise. Not even acknowledging this, she went on to cite the Mouse, a runaway neutron star discovered decades before. It lay somewhere within a thousand light-years and looked vaguely like a fleeing rodent with a long tail, because it left behind a trail of excited electrons, which were discovered by a radio telescope. All the energy in that tail came from the shock waves the Mouse excited ahead of itself. The interstellar gas and dust was slowing it, braking an entire compacted star, and the energy expended by this splashed across the sky in an extravagant signature.

  Of course, she allowed, the Mouse was just an analogy. There were details of how to estimate the braking, which demanded knowing the size of the “working surface” and interactions across it, shock waves—a zoo of astrophysical effects. Benjamin recognized areas she had worked on in her career, so her approach was not really surprising; to the man who owns a hammer, every problem looks like a nail. But this method came out of her life, giving her an assurance others lacked.

  She turned from her calculations to confront them. “And this object is doing the same. But taking the luminosity, I can find the mass that’s being slowed down by simple interstellar friction. Guess what it is.”

  She had them on puppet strings now and a pleased smile rippled. She waited.

  “A neutron star…again?” a voice called, dribbling away in self doubt; she would not be that obvious.

  “Jupiter-sized?”

  “No, bigger!”

  “An Ear
th mass, I would guess,” Kingsley put in, not to be utterly upstaged, but smiling at her audacity. Benjamin suddenly saw in the wryly appreciative cast to his face that Kingsley had a deep affection for Channing. Somehow this had eluded him through all their clashes.

  She drew it out to just the right point and then wrote a number on the board. Silence.

  “That’s about the mass of the moon,” a voice called from the back.

  “It’s small.”

  “Nothing at all like a neutron star,” a voice declared, sounding irked at being misled.

  “True. With a moon’s mass, but it makes gamma rays. Some kind of supermoon. Gentlemen, you have something really new on your hands.”

  She sat down in a free chair in the front row, next to Benjamin. As she settled in, he caught her letting go, giving way to the sudden body language of near-exhaustion. The room broke into applause. Not, Benjamin saw, at the particular brilliance of the analysis—anyone in the room could do the arithmetic and make estimates, and many no doubt would rush back to their offices and do just that, checking her—but because she had seen just the right calculation to do and had done it before anyone else. That was the trick in high-flying science: to pick the right problem just as it becomes worth doing. And she had brought it off. He had noticed that she had gotten up in the night, and in his fuzzy sleep had attributed it to her familiar medical woes. But no, she had been honing herself for this grand game, the clash of scientific ideas. She still has it, my girl, he thought with relish.

  He leaned over to her and whispered, “I knew that I’d married Miss Right, okay—only I didn’t know her first name was Always.”

  She gave him a proud, tired grin, followed by a kiss.

  6

  Most of the world’s orbiting telescopes lost much time and flexibility from always having a huge bright object nearby—the Earth. Accidentally pointing the telescope that way for even a second would fry sensitive optical systems.