Dark Secret (2016)

by Edward M. Lerner

  Cut yourself some slack, she chided herself. It’s not like you had the time to think about it, or decent options. And remember: we survived.

  She said, “I still want to know what happened to us, and where we are. Did you coax either from Marvin?”

  “More Antonio’s doing than mine, but yes. You remember how he first found the cosmic string?”

  “Microlensing. There were enough background stars microlensing to navigate by?”

  “Nothing so straightforward.” Blake hunted around the engine room until he located a plate with a half sandwich. “Back on Earth, did you ever swim underwater? Snorkel or scuba?”

  “Snorkel. Why?”

  “Did you ever happen to look up while you did, and see something unusual?”

  One January after term finals, she’d been among a bunch of cadets from the Academy who’d flown down to the Virgin Islands. What a week they’d had! Wind surfing. Paragliding. Beach volleyball. A day trip to a Mayan ruin on the mainland. And one day they had all gone snorkeling above a reef, the coral vibrant with sparkling whites, warm pastels, and shocking pinks. She remembered the fish, hundreds, sometimes thousands of them, darting and weaving in formation like flocks of birds.

  And one giant sea turtle.

  She remembered Liam, her boyfriend at the time, pointing upward when Dana looked to see who had grabbed her ankle. The turtle, blue with white speckles, longer nose to tail than she was tall, gliding majestically overhead. The top of the turtle—it was covered in overlapping leather plates rather than by a hard shell—seen as clearly as its underside. The turtle’s back was reflecting off the smooth boundary between sea and sky.

  “Total internal reflection.” She thought the startling effect had something to do with the indices of refraction of the neighboring media. Beyond some critical angle dependent on the ratio (if she remembered that correctly), all light striking the boundary bounced off. “Sure, I’ve encountered it. What’s that have to do with our situation?”

  “You would be surprised. Whatever you saw while snorkeling involved light in the water unable to cross into the air, never light in the air kept from penetrating into the water. That’s one example of the rule: total internal reflection happens within the medium having the higher index of refraction. That’s the medium with the slower speed of light.”

  Dana flexed her drink bulb, almost empty, as she pondered. “Near the string, where light is uncharacteristically fast, starlight bounces off?”

  Blake nodded. “Except for incoming light that is all but perpendicular to the string, that’s the case. The closer Endeavour approached the string, the faster the local light speed and the less starlight would reach us.”

  So much for a turtle’s back, crystal clear in reflection. Marvin’s challenge had been more like a nighttime plunge into the ocean depths. She tried to imagine following the distant, unseen surface with nothing to guide her but occasional faint glimmers of starlight.

  The tepid dregs in her drink bulb couldn’t touch her resurgent chill. She hoped Blake hadn’t noticed her trembling.

  Dana said, “Leaving Marvin to infer the location of the cosmic string from the level of incident starlight.” She shifted her empty bulb from hand to hand. “Still, when the string twisted or curved or got denser unexpectedly, when the starlight went away, how did he know which way to veer? The distribution of stars isn’t all that constant.”

  “Know? A cynic would say, ‘guess.’” With a sour expression, Blake set down his plate, the food untouched. “Marvin didn’t always know which way to turn, especially as external sensors degraded. Whenever it guessed wrong, whenever by accident it veered the ship toward the string, it needed both drives to back away to safety.”

  No wonder they had all but exhausted their supply of deuterium!

  Dana said, “I’d call Marvin a freaking genius, except for one thing. We aren’t supposed to be here. Why didn’t we break free from the string after a couple of light-years?” Like we told Marvin to do.

  “We were trapped,” Blake said. “Breaking free would have involved prolonged thrusting at right angles to the string. We’d have been broadside to the oncoming radiation all the while. It was bad enough that we got short blasts of radiation with every orbit-maintenance maneuver.”

  Dana considered. Endeavour’s only meaningful shielding was fore and aft: what they had retrofitted near the bow, plated over the decks of the bridge and crew quarters, and around the fusion reactor. Perhaps more than the long years of cold sleep were behind how crappy she felt, and Carlos’s deterioration. “So breaking away would have given us a lethal dose.”

  “Other than by flying off an end of the cosmic string, yeah. And the attempt would have fried Marvin, too. Its circuits aren’t much happier with radiation than our cells are.”

  “So we flew to the end,” she said.

  “As fast as the ship could deliver us there.”

  “What if the string had been a lot longer?”

  “Antonio says this string couldn’t have been too much longer,” Blake said. “Much more mass would have had a visible effect on the local distribution of stars. A longer cosmic string would have been detected centuries ago.”

  Dana preferred that answer to the notion that once Endeavour exhausted its deuterium, they would have been done for.

  Blake yawned, and Dana followed. It was ridiculous that after forty-five years asleep, her body cried out for a nap. Ridiculous but not to be denied for much longer.

  She said, “Bottom-line it for me. Where the hell are we?”

  Blake yawned again. “As the interstellar-capable crow flies, about one hundred light-years beyond the Coalsack. Call it seven hundred forty light-years from Sol system. But we took the scenic route: sweeping around the nebula, not through it. If the string had run through the cloud, gravity would have collapsed a big clear channel through the Coalsack long ago.”

  “Any idea how far we actually came? As the ship actually flew?”

  “Marvin knows how long we accelerated and how hard. It knows how long we coasted. From that, at least a thousand light-years. Jumoke would have been proud of her DED: we peaked out a little above thirty-nine times normal light speed.”

  Thirty-nine times? Fuzzy-brained from exhaustion, or radiation, or years in cold sleep, stifling yet another yawn, Dana had to ask, “At least a thousand light-years?”

  “Will you quit that, please,” Blake yawned back. “Yeah, at least. The estimates rely on elapsed time as measured by the ship’s clock, and in our own frame of reference, by definition, our clock ticks normally. Did we experience time dilation relative to home? We don’t know.

  “So: the estimates are in the ballpark if the local light speed was way faster than forty times normal. Otherwise not. We have no way to know. And do you remember the pulsars Antonio is using as beacons? Like any star, pulsars drift. Our locational fix is as iffy as our time fix.”

  If we can’t know where we are, I’ll waste no more energy thinking about it. Because I have quite enough to worry about.

  Dana said, “So we’re on the wrong side of a dark nebula, in galactica incognita. No astronomer has ever seen this region of space. I suppose that means no one knows where we might find a planet suitable for establishing a colony.”

  Blake arched on eyebrow. “You thought this was going to be easy?”

  16

  With a decent telescope and a spectrograph, a ship could analyze asteroids from a distance. Most asteroids were mere rock, worthless—but a few were treasure troves of precious metals and rare-earth elements. Spot an asteroid like that and stake a claim, and your fortune was made.

  Clermont, become Endeavour, carried a decent telescope. Emphasis on the past tense. Decades of pounding by cosmic rays had degraded that telescope into something at which Galileo would have sneered.

  At least that was what Antonio had to say on the subject.

  “We don’t have replacement mirrors,” Blake reminded. He was as tired of repeating himself as
he was of stacking-room-only meetings on the bridge. Though he did not mind Rikki sitting on his lap. Forty-five years was a lot of abstinence, even asleep and frozen solid. “And before you ask, I can’t polish and replate these mirrors, either. I’d have to make the tools to make the tools to make the tools, with maybe a few more iterations. Don’t even ask how long that’d take. A while.”

  “We can’t afford rations for ‘a while,’” Dana said. “We need to get somewhere.”

  “Look, Antonio,” Rikki said. “I’ll never know half the astronomy that you do, but I know something of the history of the subject. The Galileo crack is an exaggeration, don’t you think? And not just because his telescope didn’t use mirrors.

  “By two centuries ago astronomers had approximated the distance to nearby stars. They did it without any computers worth mentioning. They did it, being earthbound, despite atmospheric shimmer blurring every observation. We have a modern telescope, even if it is a bit dinged up, and Marvin to handle all our calculations, and no atmosphere to distort our viewing. I refuse to believe we can’t match twentieth-century science.”

  “I suppose,” Antonio conceded.

  “Walk me through the process,” Dana said. “How would we measure the distances?”

  “Sure,” Rikki said. “By way of an analogy, hold a finger in front of your nose. With one eye closed, look at the finger. Notice where the finger appears against the background of the bulkhead behind it. Now switch eyes.”

  “The finger seemed to jump,” Dana said.

  “Right. And knowing the two viewing angles and the distance between your eyes, you could calculate the location of your finger relative to your face.”

  “My finger represents a star,” Dana said. “And my two eyes?”

  “Two separate sightings on the star. For old-time astronomers, that meant observations made six months apart. Earth’s orbit is about one thousand light-seconds wide. The parallax technique located stars as remote as a few hundred light-years.”

  “We’re not orbiting…,” Dana began. “Scratch that. We’re moving.”

  Blake did rough math in his head. “Every three hours or so, we’re crossing a distance like the width of Earth’s orbit. In a day, even with our scarred-up mirror, we should have lots of good readings.”

  “Can we focus on individual stars?” Dana asked.

  “Focus?” Antonio stroked his chin scar. “Not to my satisfaction. But yes, we can locate and take bearings on individual stars.”

  “Good,” Dana said. “You and Rikki, get to work.”

  *

  Blake gazed around the machine shop, waiting for something to happen. Nothing did. He rearranged the tool cabinet. He buffed a streak of grease off a bulkhead. There wasn’t room to pace, so he shifted his weight from one leg to the other.

  He did not want to be here. But the only meaningful activity aboard was on the bridge, and he could contribute nothing to star hunts.

  “It’s just milk,” he said.

  “And you’re a pile of common elements, worth pocket change.” Carlos sighed without looking up, intent on the scrolling readout from a portable synth vat. He stood, hunched over the workbench. The shop stools and workbenches fit Blake.

  “Well?” Blake finally prompted. “Did I make milk, or not?”

  “Milk is a complex suspension of proteins, fats, sugars, vitamins, and minerals, and you’re trying to synthesize all those. Give me a minute to sanity-check what we have here.”

  “A cow does it faster,” Blake said.

  “Do you see a cow on this ship?”

  “No, alas. I would enjoy a good steak.”

  The words just popped out. A moment after, Blake realized that someone named Patel might be Hindu. No one ate beef on Mars—raising cattle took too much water and feed. Grain or grass, Mars didn’t have enough of either.

  Only now Mars had nothing.

  Wistful, embarrassed, and sad: all in an instant. “Please excuse my obliviousness, Carlos. If I offended you, I apologize.”

  “My father would have taken offense. He grew up in Bangalore, didn’t emigrate till he was twenty-eight. That you would eat beef doesn’t matter to me in the slightest.”

  “It’s hard,” Blake said. “Losing our families, and not even getting to say goodbye.”

  “It was different for me.” Carlos turned away from the synth vat. “My parents and a brother died in the Blue Plague when I was a child. My adoptive parents, from my mother’s family, weren’t religious. Had they been, it would have been Catholicism.”

  “I’m sorry,” Blake said. Blue Plague had swept Mars in 2120, when Carlos would have been about ten. Hell of a nasty way to lose anyone. Hell of an age for a child to lose his parents. “But you had other brothers or sisters?”

  “I was the fourth of five children. Sanjiv, the brother taken by the Plague, was the oldest. He was in university, studying nanotech. I always looked up to him; my involvement with nanotech maintains the connection. The rest of us? After the Plague, we were close. We had to be, coming into a household that already had six children.”

  A middle child and an orphan. It explained a lot about Carlos.

  The synth vat beeped.

  Carlos checked the readout again. “Ready for a drink? That’s the final test.”

  The fluid Blake decanted looked like milk, if with the blue tinge of the skimmed variety. It smelled like milk. It tasted like milk. So why was Carlos watching him expectantly?

  Then Blake’s stomach lurched.

  Carlos leapt back off his stool, although nothing had come up. Not quite.

  There wasn’t a rag or towel in sight, and Blake wiped his mouth on his sleeve. “Where did I go wrong?”

  “It’ll be faster to say what you did right.”

  Ignoring the ominous gurgle in his stomach, Blake said, “You may as well give me the complete version. It’s something to do while we wait.”

  17

  Antonio flopped in his hammock like a fish out of water, exhausted but unable to sleep.

  How long had he worked without a break? Rikki had proposed they take a breather, then Dana had. Somewhere along the line Rikki must have left on her own, because when she had returned to the bridge with food trays he realized he hadn’t seen her for a while.

  Not until he had nodded off in his seat and startled himself awake with a loud snort had he conceded to reality.

  On the bridge or here in the crew cabin, eyes open or shut, it made no difference. His mind churned with vectors and parallax measurements and error bars. For star after star, there were estimates of mass, and age, and metal concentrations. About half the stars were binaries, and those added orbital parameters to the numeric stew.

  And planets discovered? That also was a number. Zero.

  Numbers had always been his friends. Unlike people, numbers were precise, trustworthy, and unambiguous. Numbers made sense. And then—

  From an adjacent hammock, a shadowy presence in the dark, Li said, “Once you find our new home, we become parents to twelve thousand children. Imagine that.”

  “I…can’t,” he’d stammered.

  She laughed. “Soon you won’t have to imagine it. You might want to sleep while you have the chance.”

  “Point taken. Goodnight.”

  Twelve thousand. That single, chilling number all but drove the rest from his head.

  I’m one sixth of humanity, Antonio thought. Sixteen and two-thirds percent. Zero point one six six six six….

  He could recite sixes to himself without end, and never reach peace of mind. Against all odds, he had saved a few people. That he could believe. But that he should have a role in raising twelve thousand children, and then the offspring they would bear? These were numbers beyond logic, beyond sense, beyond comprehension.

  Yet here you are, the memory of Tabitha reminded. She was smiling. In his mind’s eye, she always smiled.

  Of course his mind’s eye did a better job than his physical eyes of looking at people.


  With an even warmer smile: You’ll do fine, honey. Somehow, you always do.

  From the next hammock: even breathing. Had Li fallen asleep?

  Six of them to raise thousands, if not in person then by setting the example. The longer he spent with his shipmates, the more impressed he was with Hawthorne’s selections—

  Except for one glaring lapse: not one of them had ever raised a child. Carlos had fathered a child, in his second marriage, but from everything Antonio had heard, Carlos’s contribution to rearing his daughter had been limited to sending money and keeping his distance.

  Neither was an option here.

  Quit worrying, Tabitha gently scolded, still smiling. I know you. You’ll be a great dad.

  Soon after meeting Tabitha, he’d deemed her as trustworthy as numbers. With a grin, she had called the comparison high praise—and it was like he’d been struck by lightning. Another person could understand him. In that instant he had known she was the one.

  He would have believed the affirmation coming from Tabitha. He had believed everything she said. But believe his own wishful thinking, words put into Tabitha’s mouth? That his subconscious would undertake such a pitiful ruse only terrified him further.

  Twelve thousand young minds to educate. Even sooner, twelve thousand mouths to feed, cribs to build, and bottoms to wipe. Twelve thousand eager gazes to avoid.

  “You’re restless,” Li murmured. “Something I can help with?”

  You’ve helped enough. “Twelve thousand diapers to change. It seems like a lot.”

  “Isn’t that the truth,” she said. “You can take comfort that we have far fewer artificial wombs. Though once we have a world into which to spread, I expect our techies will find a way to construct more. And of course there is the old-fashioned way to make babies.”

  Shelter for thousands. And food. Clean water. Sanitation. Power. Healthcare. Clothing. A city’s worth of people—and a city—all somehow to be provided on an unknown planet.