Seeker

by Jack McDevitt

  “We already know.”

  “All right. Good. That might make it possible. Send me the data. I’ll look everything over and get back to you.”

  “Thanks, Shara.”

  “My pleasure. I’m glad to help. It’ll be a break from my routine. Is there a deadline on this?”

  “No,” I said. “It’s waited this long; I assume it can wait a bit longer.”

  She laughed. “Get it to me tonight, and I’ll try to have something for you tomorrow.”

  “You were right about the time of the event,” she said next evening, as we sat at the Longtree, sipping cocktails. “It happened March 1, 2745, on the terrestrial calendar.”

  “That’s only a couple days away from what we figured.”

  “We’re talking calendars rather than time itself,” she said. “It’s hard to deal with this sort of thing because of the odd things that happen with time when the objects are hundreds of light-years apart.”

  “All right,” I said. “We know when it happened. Where do we go from there?”

  A singer was doing “Fire and Ice.” It was cold and wet outside. But the Longtree was filled to capacity. A wedding party had taken over one wing, and another large group was celebrating something. Couldn’t tell what. There were occasional bursts of laughter around the room. In the center of the dining area, several couples were dancing.

  “Chase,” she said, “we know where the gas giants were at the time of the event.”

  “Okay.”

  “They were undisturbed by the passage. That probably lets out your black hole. Had the intruder been massive, really massive, they would have been disrupted, too. But in this case, their orbits don’t seem to have been influenced at all.”

  “That tells us what?”

  “That the intruder was less than a tenth of a solar mass.”

  “Okay.” I didn’t see how that could help. But she seemed to know where she was headed.

  She finished her cocktail and ordered another round. “Might as well,” she said, “as long as Alex is feeling generous.” Rainbow, of course, was paying for the evening.

  “Absolutely. Help yourself.”

  “All right. So Margolia’s orbit gets stretched, and its moon goes south. The other terrestrial world, Balfour, is tossed out of the system altogether. That suggests an intruder mass at least a hundred times greater than Margolia.”

  “Okay.”

  “My best guess,” she said, “is a mass equivalent somewhere between a Jovian and an M-class dwarf star.”

  “Shara,” I said, “I know you’re interested for academic reasons. But is any of this going to help us find Balfour?”

  “Ah, you don’t have the patience you used to, Chase. If we split the difference between the Jovian and the class-M, we’re in brown dwarf territory.”

  “Brown dwarf.”

  “Yes. It’s a star that never quite got off the ground. Not enough mass. So it didn’t ignite.”

  “It’s a dark object, then.”

  “No. Not necessarily. They have enough energy to glow. They stay warm for a long time.”

  “What generates the energy?”

  “It’s left over from their formation. What I’m saying is that this thing won’t look at all like a star. It wouldn’t be a bright light in the sky. But if you got close enough, you’d be able to see it.”

  “What would it look like?”

  She thought about it. “It might resemble a gas giant illuminated from within. It would have clouds. Probably a muddy brown.”

  “That seems an odd color.”

  Shara had a tendency sometimes to go into lecture mode. She did it now. “Younger dwarfs are usually blood red. They’re just radiating the heat generated during formation. As they age, they cool off. More and more molecules form in their atmospheres, and they acquire clouds.”

  “What kind of clouds?”

  “Ferrous and silicon compounds, mostly. With some curious weather patterns. Eventually they become dark red. In time, they’ll fade to reddish brown, and finally to brown.”

  “Okay. And if one of these things came through a planetary system, it could raise hell?”

  “You bet. Look, Chase, it’s massive. Probably one percent of standard solar mass. That sounds small, but it’s a tight little package. If it gets anywhere near you, look out.”

  “Can you tell what its path might have been through the system?”

  “More or less. Mostly less.”

  “Explain?”

  “I tried a trillion combinations of intruder inclination, periastron distance, mass, and velocity.”

  “Wait a minute,” I said. “Try it in the mother tongue. What’s periastron distance?”

  “When it’s closest to the sun.”

  “Okay.”

  “So I tried all that to see if I could track it. Something that would produce the results we see. I’d say it entered and exited the system on a path that was mildly inclined to the plane of the planets, with periastron occurring between the orbits of Margolia and Balfour. Margolia, by the way, was the inner of the two class-K worlds.”

  “That doesn’t sound like a guess.”

  “It isn’t. There are limitations on what Margolia’s orbit could have been. If Balfour was also in the biozone, as you’re saying, it would have had to be more remote. Anyway, with Balfour in the equation, it becomes possible to fit the orbits of the dock, the moon, and Margolia together.”

  “That’s why we weren’t able to make the orbits intersect,” I said.

  “Correct. You needed the fourth planet.” Her eyes were alight. She loved talking about astrophysics. “This thing would have been massive. If it had gotten really close to the central star, it would have taken it out. Like the one at Delta Karpis in the last century.”

  “Okay.”

  Our drinks arrived. She tried hers and set it down without reacting to it. “All right,” she said, “we also know the two gas giants were on the far side of the system when the dwarf crossed their orbits. So far, so good. But the two terrestrials weren’t so lucky. It passed close to them.”

  “Shara,” I said, “why do we care so much about the dwarf?”

  She pointed at my drink. Have some. I complied. “Because the dwarf can tell us where Balfour is.”

  “Wonderful.”

  “Not so fast. That brings us to the bad news. I can’t give you even a rough estimate where Balfour might be unless we can find the brown dwarf.”

  “Why?” I asked.

  “Find the brown dwarf and that gives us its mass, current position, and velocity. From that we can work out its path through the Tinicum system. Then we can put together a decent estimate where we might find your missing world.”

  “Shara, haven’t we just moved the problem around? How do we find the brown dwarf?”

  She was looking at something over my shoulder. “Don’t turn around,” she said.

  I waited a few seconds, and saw a waiter leading a tall male in a dark jacket past us to a corner table. He looked pretty good, and his gaze swept across Shara, and held. There was an exchange of nonverbals and he moved on. Shara grinned at me as he passed out of her field of vision. “Target of opportunity.”

  Maybe she hadn’t changed as much as I’d thought. “The brown dwarf,” I said.

  “Yeah.” She was still distracted. “Well, the good thing about all this is that it can’t have gone very far in nine thousand years. Certainly less than a light-year. It’ll be quite bright in the near infrared, say tenth or at worst fifteenth magnitude.”

  A young woman cruised past, headed for the guy. Shara shook her head. “Pity,” she said.

  “So we can find it?”

  “It’ll cost.”

  “What do we have to do?”

  “Go hunting for it. First you’ll need to persuade Survey to let you have a ship.”

  “Why?” I asked. “We have the Belle-Marie.”

  “It can’t do the job. You’re going to need to deliver a couple
of wide-field telescopes to the search area. A private yacht wouldn’t be able to handle that. Anyhow, Survey has ships already equipped to do this kind of thing.”

  “I’ll talk to Windy.”

  “They’ll want somebody from Survey to go along. It’s in the rules.”

  “What actually would we need to do? How do wide-field telescopes work?”

  “They come in pairs. We set them well apart and let them do a simultaneous survey of the sky. The brown dwarf will stand out.”

  “You’re sure?”

  “Trust me.”

  “All right. Will the onboard AI be able to take care of things without my getting too much involved?”

  “No,” she said. “You’ll have to provide some guidance. The ship will have the equipment, but this operation’s a bit different from what the AIs normally do.”

  She explained the procedures. Dinner arrived. Vegetables with salads, and sliced chicken. We were both hungry. She dived in, but I was still trying to write down everything I was hearing. “I’ll never get all this straight,” I said.

  “Sure you will. I tell you what, before you leave, I’ll give you a crash course.”

  “Okay.”

  “You’ll be fine, Chase.”

  “Is there anybody out there with the mission? Somebody I could ask, in case we have a problem? Who knows how these things work?”

  “One or two, maybe,” she said. “I’m not sure. But don’t worry. The person Windy sends with you will know how to operate the gear.”

  I wasn’t comfortable with the arrangement. It felt like one of those situations where we’d get out there and discover I didn’t know what I was doing. And the guy they’d sent along would look puzzled and comment how it had been a long time. So I took a plunge. “Listen, you said that Survey would want to send a rep with us.”

  “I’m busy, Chase.”

  “I’d appreciate it. I’d consider it a personal favor.”

  She lifted a piece of tomato on her fork and stole a glance over her shoulder at the corner table. The guy was absorbed in his companion.

  “I’ll never ask for anything again,” I said.

  “I’m sure.” She tapped her fingernails on the side of the wineglass while she thought about it. “It’s not that hard, Chase.”

  “This is a piece of history. Wouldn’t you like to be there?”

  “I think the history’s already been made, Champ. I should have gone on the earlier flight.”

  “Shara, Alex’s instincts are usually pretty good. There might be something more. Something pretty big.”

  She was already well along on the meal. I knew she’d be reaching for the dessert menu next. Shara was one of those irritating people who eats what she likes and never seems to pay a price. “We’re talking some serious time here, Chase. What about my social life?”

  “We’ll party on the way.”

  Getting a ship turned out to be complicated.

  Shara was correct as far as it went when she said official policy required someone from Survey to be on the flight. But the someone had to be the pilot. “There are no pilots available,” Windy told me. “I can check to see whether anyone would volunteer to go. But it would be overtime. And I doubt we could find anybody anyhow.” She went on to tell me who was currently on free time and why they would not be responsive to come back to work.

  “How about me?” I said. “I’m licensed.”

  “For Arcturus-class?”

  I’d been piloting yachts and small commercial. “Not exactly,” I said. “But how complicated can it be?”

  “It’s the rules, Chase. Sorry. I have no choice.”

  Windy made some calls and, as predicted, both available people said no. Survey pilots are pretty well paid, and they don’t get a lot of free time at home. Had we been at one of the outposts, or on a station somewhere, we’d have had no problem. But in Andiquar, it was no go.

  So Alex signed me up for an accelerated program. And that’s how I became qualified for the next level of superluminal. I have a Longstar license now, which is a level beyond Arcturus. I didn’t really want to get that one either, but that’s another story.

  Three weeks after my conversation with Windy, I had my license, and she took me on as a temporary, thereby allowing her to classify me as an employee.

  Shara in the meantime wondered what the fuss was about. “I’ll never figure out why anybody would pay large sums of money for antiques. I understand their archeological value. But in this case, even that seems problematical. All you can hope to do is find out how a few diehards spent their last days. To be honest, I think you’d pay them more respect by letting them be.”

  I’d been empowered to offer her a third of any profits we might realize if the discovery were made and after Survey got its share. That got her attention. “How much are we talking?” she asked.

  I provided a modest estimate, based on what the handful of Seeker trophies had brought. She was impressed. “The business pays enough to get by on,” I said.

  “I guess. Well, okay, Chase. I can’t very well turn that down. But I still can’t imagine why the Margolians would try to get over to a world that’s going into the deep freeze. I think this is wrongheaded all around. But all right. What’s to lose?”

  Windy showed up a few minutes later, and Shara told her she was going with us. Windy’s color changed. “I’d thought better of you,” she said.

  So on a cool, windy day in late summer, in the year 1430 since the Foundation of Rimway’s Associated States, Alex, Shara, and I caught the shuttle to Skydeck, and boarded VHY-111. The Spirit. Within an hour we were on our way back to Margolia.

  THIRTY

  Hitch your wagon to a star.

  —Ralph Waldo Emerson,

  Society and Solitude, 1870 C.E.

  The Spirit was twice the size of the Belle-Marie, with accommodations for eleven passengers. The life-support section consisted of the bridge, twelve compartments (one for the pilot), two washrooms, a compact storage area, an operations center, a workout center the size of a large closet, and a common room. The latter was considerably more spacious than the one Alex and I were accustomed to. That said, the Belle-Marie nevertheless made for easier living. The Spirit was strictly a vehicle to transport people from one place to another. There were no amenities.

  The rest of the ship, launch bay, main storage, and engine access, all below, was normally maintained in vacuum to preserve resources. There was also a parts locker and systems access area immediately beneath the bridge. “Control units are there,” I explained to Shara, “in case anything needs tweaking. And the black boxes for the AI are there.”

  I went through my preflight checklist and set our jump for nine hours post departure. Then I strolled back to the ops center, where I found Shara seated in front of a display. “Good,” she said. “I was just coming to get you.”

  “You want to talk about our target?”

  “Yes.” She showed me a star and a lesser light. “Tinicum 2116,” she said. “And Margolia.”

  “Okay.”

  “Let’s back Tinicum up nine thousand years.” Coordinates rippled along the lower right-hand corner, slowed, and stopped. The star moved halfway across the room. “During the period since the event, it traveled somewhat more than a half light-year. This is where it was when impact occurred.

  “We know from the effects of the disruption that the intruder came through on an angle close to the plane of the planetary system. We also know that, by now, it will have gone about the same distance that Tinicum did. A half light-year, more or less.”

  “Okay.”

  “Keep in mind that’s an estimate. But it should be reasonably accurate. What we don’t know is which way it was traveling.”

  “Okay. So we can draw a ring around the point of impact, a half-light-year radius—”

  “—And the intruder is somewhere along the circumference. Yes.” She drew the ring. “That’s our search area. The target might be on the far side, or on
the interior, probably a bit above or below the plane. But it’s there.”

  “That looks like a big neighborhood,” said Alex. I hadn’t seen him come in.

  “It is,” she admitted. “But it’s small enough that it makes a search feasible.”

  “How fast is the dwarf likely to be moving?”

  “About the same velocity as Tinicum. Roughly twenty kilometers per second.”

  “So,” said Alex, “it’s possible the thing might still be close to the system? Traveling with it?”

  “Close is a relative term. It passed through the system, so we know there’s some deviation.”

  “All right. Where do we start?”

  “We make for the point of impact. Once there we deploy our telescopes on opposite sides of it. At a range of”—she hesitated, considering it—“let’s make it five AUs. We want the telescopes ten AUs apart.”

  I spent the next few hours boning up on brown dwarfs. Shara was right when she said there are a lot of them. According to Survey there were hundreds in the immediate vicinity of Rimway’s sun. That didn’t make me comfortable. But then it’s a vicinity that incorporates a lot of empty space. Modern technology makes travel virtually instantaneous, and it causes you to forget just how big everything is. As I think I remarked somewhere else.

  Brown dwarfs are not massive enough to burn hydrogen, so they don’t ignite, the way a full-fledged star does. But they still give off considerable heat, more or less from tidal effects. They can be observed through infrared telescopes, in which they will appear as a faint glow.

  Get close enough to the average brown dwarf and it’ll look like a dim star. It’s only .00004 times as bright as the sun, either ours or Earth’s. Still, according to the book, they’re pretty hot. Temperatures on the surface range up to 3,200 degrees C. At that level, substances like iron and rock occur as gases.

  During the cooling process, they generate methane. The gases condense into liquids and form clouds, which contain some of the heat. But continued cooling results in storms, which in turn clear off the clouds. When that happens, infrared light from the heated atmosphere escapes, causing the dwarf to brighten.