Eater (4 page)

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 Benjamin’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 The site of the now-outdated Very Large Array, Socorro, New Mexico, still had a practiced set of house theorists and observers, and Benjamin knew several of them well.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/R
²
, 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 Earth 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.

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.

So astronomers avoided their home planet if they could. Placing large Big Eyes at Earth’s Lagrangian points helped—orbiting sixty degrees fore and aft of the moon’s position in its orbit, far from the blue-white glare of the planet’s ocean and sky.

Without the sunlight reflected from the Earth’s disk, telescopes could cool to a few degrees above absolute zero. This helped enormously when looking in the infrared, for then the telescope body itself did not emit much radiation at the crucial frequencies. With a hundred times the area of the much earlier Hubble Space Telescope, the Big Eyes could see dim objects a hundred times fainter.

But when pointed at the elusive quarry, the Big Eyes showed only a dim blur. They could not see in enough detail to tell what it was. As Kingsley remarked acerbically, two further days of effort on a global scale served merely to give it a name. One was suggested by Channing in an offhand moment: “X-1.” She had explained, “X because we don’t know what the hell it is, and one because there may be more.”

But it sounded too much like a weapon or jet plane, so everyone just called it “the intruder.”

Stymied, the worldwide network of observers went back to telescopes firmly fixed on Mother Earth.

Earth-based instruments used adaptive optics—mirrors that adjusted second to second, offsetting the dancing refractions of the air above them. Several of these sat atop Mauna Kea, the best all-around observing spot in the world. The aim of the newest sixteen-meter reflector ’scope, using adaptive mirrors, was to fetch forth images of Jupiter-sized planets orbiting nearby stars. Pricey Earth-based ’scopes were still far cheaper than space eyes, which had to carry a guidance system to keep them pointed accurately while orbiting at 27,000 kilometers per hour.

But the sixteen-meter ’scope could not resolve the blob of visible light that “X-1” gave off.

To reliably see another star’s Jupiter-sized planets, humanity had to go to its own Jupiter—or rather, to send a robot. Able to see in the infrared with meticulous accuracy, the Deep Space Infrared Telescope hung as far from the sun as Jupiter itself, orbiting high above the ecliptic plane. This kept it cold and out of the plane of dust that clogged the inner solar system. The enemy of good, deep “seeing”—to use the astronomer’s jargon—was the glow of sunlight scattered by that orbiting debris. Its dim radiance had been discovered in 1661 and it was still termed the “zodiacal light.” In excellent seeing conditions, from Earth one could watch the plane of dim gray light stretch across a winter’s night. This dust-reflected sunlight perpetually brightened the sky of the inner solar system. The dust declined in density far from the sun, and sunlight dimmed, so that now astronomers were driven to the outer reaches.

There a thin beam orbited, a hundred meters long and crafted to within a ten-thousandth of a millimeter: the Long Eye. To see a planet around another sun demanded that the Long Eye blot out the star’s infrared emission, which was a million times brighter than the world being sought. Then the
telescopes spaced at regular intervals along the length compared the phases of the light they received from near the star. Matching and subtracting, an onboard computer sifted through a torrent of noise for the faint, steady signal of a tiny planet, sending out the message of its own existence.

Standing beneath a clear sky, one’s unaided eye could see details on the moon about a tenth of the moon’s diameter. At the same distance, a Big Eye ’scope typical of those standing on Mauna Kea could make out an astronaut standing on the moon. With the Long Eye—and some luck—one could make out the astronaut holding up fingers—and count them.

The Long Eye was painstakingly studying the zone around likely candidate stars, seeking evidence of life. By looking carefully at each color of the light from the target world, it could in principle see the fine details of absorption by water, oxygen, or carbon dioxide—telltale gases of life.

This stretched array now searched for a dot at the very edge of the solar system, a target its designers had never conceived.

“Got it!” Amy cried, jabbing at a large computer screen. The data had just come over the astro-Net connection.

They crowded around. The de facto working group was only four: Amy, Kingsley, Benjamin, and Channing. Of course there were subgroups laboring over parts of the problem, but by unspoken agreement they had started meeting in each others’ offices whenever a fresh piece of data seemed in the offing. Martinez had approved this catch-as-catch-can method, suggesting to Benjamin, “Whatever works, go for it.”

They all took in the new result at a glance. There were small gasps. But they left it to Channing to note her own triumph. “Looks pretty small.” A bright spot sat at one end of the radio finger: starship-like.

“It’s fully resolved, though,” Amy said. “Looks like a circle. A moon? At its distance, let’s see…ten milliarc-seconds…Geez. No moon, not at all. It’s only a few kilometers across.”

“What? That can’t be right.” Kingsley peered at the screen’s side panel of data and gazed off into space, making his own reckoning. He blinked. “Um. I’m afraid it is.”

“Afraid?” Benjamin chided.

“Because it means something is wrong with Channing’s rather nice piece of work from two days ago. This object cannot have the mass of a moon. It’s far too small.”

Benjamin wanted to defend her, but Channing spoke up quickly, despite a fog of fatigue that had descended upon her in the last hour.
Damned if I’ll leave early today
, she thought adamantly,
and let Kingsley call the tune
.

If only her head would stop spinning…“Let’s not rule out anything until we fit the pieces of this jigsaw puzzle together.”

Kingsley said in a let’s-be-reasonable tone, “Your estimate included a characteristic size, which we now see was far too large. So you derived a larger mass—”

“Not so fast,” Channing said. “What’s the rest of the Long Eye results?”

Benjamin punched some keys and peered at a sidebar that popped up. “They’re logging in the spectrum…processing…Looks like an excess of blue shifts.”

Channing beamed in a way that, from his expression, she could tell that Benjamin had not seen for a long time. “Which means it’s decelerating.”

“Just as you said,” Kingsley allowed. “That I’ll grant. But your calculation still makes no sense—quantitatively.”

“Look,” Channing pressed back, “I estimated in my first equation—”

“We’re missing the big point, aren’t we?” Plainly Benjamin decided to intervene before talk descended into another technical wrangle, as it had so much these last few days. Often the devil was indeed in the details, but he had a way of pulling specialists, including most definitely herself, away from their narrow issues to face the larger picture.

Kingsley smiled, seeing the point. “It is deliberately slowing to enter the solar system? The starship hypothesis.”

“But to be so bright, it must have a huge mass,” Channing said. “No starship would be so heavy.”

Benjamin nodded. “A big contradiction.”

Long silence. She had often heard historians of science go on about how a great scientist had the courage of his convictions, stuck it out through opposition, and so on. Until this moment she had not
felt
the implied sense—that sometimes you had to take the big leap: buy two apparently conflicting ideas and fuse them.

Should she?
What the hell, you only die once
.

“Maybe we’re both right. It’s a lot of mass packed into a tiny package.” She had to put all her effort into getting the rest of the words out. Her mind was perking along just fine, but her body wanted to curl up and go to sleep. “After all, that few kilometers across is an upper scale. This thing must be lighting up a lot of gas around it. It could be smaller than we think. A lot smaller, even.”

They all looked at each other. Another long silence.

She thought giddily,
He who laughs last just thinks slower
, but nobody laughed at her implication. To her vast and abstractly distant surprise, they all, one by one, nodded.

Within the hour, Channing was leaning back and breathing steadily, just holding on to watch the show. It took fewer muscles to smile than to frown, sure enough, and fewer still to ignore people completely. But she had shrugged off Benjamin’s efforts to take her home.

She heard boss lady Martinez say tensely, “I’ve got to get up to NASA, NSF. Maybe even on to the White House.” She smiled slightly, relishing the moment. Even if she was feeling light-headed and Martinez’s words did come hollow-voiced, like a speech given down a long tin pipe.

Not a moon, no. Something much more interesting.