Thunderhead

by Douglas Preston

  Holroyd frowned sharply. “Like what?”

  “A place on the expedition.”

  Holroyd felt his heart accelerate. “What did you say?”

  “I think you heard me. We’ll need a remote sensing and computer specialist. Can you handle communications gear?”

  Holroyd swallowed, his throat suddenly dry. Then he nodded. “I’ve got gear you’ve never even dreamed of.”

  “And how are you set for vacation? Could you take two, maybe three weeks off?”

  “I’ve never taken a vacation,” Holroyd heard himself say. “I’ve got so much time accrued, I could leave for six months and still get paid.”

  “Then that’s it. You get me the data, and I get you on the expedition. I guarantee it, Peter, you won’t be sorry. It’s an adventure you’d remember for the rest of your life.”

  Holroyd glanced down at the woman’s hands, tapered and beautiful, clasped together expectantly. He had never met anyone so passionate about something. He realized he was having a hard time catching his breath.

  “I—” he began.

  She leaned forward quickly. “Yes?”

  He shook his head. “This is all too sudden. I have to think about this.”

  She looked at him, appraisingly. Then she nodded. “I know you do,” she said softly. Reaching into her purse, she pulled out a piece of paper and handed it to him. “Here’s the number of the friend’s apartment where I’m staying. But, Peter, don’t think too long. I can only stay a couple of days.”

  But Holroyd barely heard her. He was putting something together in his head. “I’m not necessarily saying I’ll do it, you understand,” he said in a lower tone. “But here’s how it could work. You wouldn’t need to put in a request. The shuttle’s devoting the last three days of the mission to radar sweeps, sixty-five orbits at varying latitudes. There’s this mineral exploration company that’s been wanting a sweep of some areas of Utah and Colorado. We’ve put them off for a while now. I could fit them into the lineup. Then I’d extend their run slightly to get the areas you need. The only thing you’d have to do is put in a purchase request as soon as the data is downloaded from the shuttle. Normally the data is proprietary for a couple of years, but the right kind of academic requests can get around that. I’d lead you through the red tape when the time comes.”

  “A purchase request? You mean I have to pay?”

  “It’s very expensive,” said Holroyd.

  “What are we talking here? A couple of hundred bucks?”

  “More like twenty thousand.”

  “Twenty thousand dollars! Are you crazy?”

  “Sorry. That’s something not even Watkins can control.”

  “Where the hell am I going to get twenty thousand dollars?” Nora exploded.

  “Look, I’d be arranging an alteration in the orbit of a United States spacecraft for you. That’s bad enough. What else do you want me to do, steal the damn data?”

  There was a silence.

  “Now there’s an idea,” said Nora.

  7

  * * *

  IF NORA HAD EVER WALKED INTO A HOTTER, stuffier place than Peter Holroyd’s apartment, she couldn’t remember it. The air was not just dying here, she decided; it was dead and decomposing.

  “Got any ice?” she asked.

  Holroyd, who had walked down the four flights of stairs to retrieve his mail and open the door for her, shook his shaggy head. “Sorry. Freezer’s busted.”

  Nora watched him sort through his mail. Below the mop of sandy hair, the very white skin of his face was stretched over two prominent cheekbones. As he moved, his limbs never seemed to be in the right place, and his legs seemed a little short for his narrow torso and bony arms. And yet the overall impression of melancholy was countered by a pair of intelligent green eyes that looked hopefully out on the world. His taste in clothes was questionable: striped brown polyester pants, topped by a V-neck short-sleeved checkered shirt.

  Grimy yellow curtains flapped apathetically in the travesty of a breeze. Nora walked to the window, glancing south toward the dusky boulevards of East L.A. Then she looked down toward the nearby intersection and the front window of Al’s Pizza. She’d spent the last two nights at a friend’s house in Thousand Oaks. This was an ugly little corner of L.A., and she felt a sudden sympathy for Peter and his longing for adventure.

  She took a step back. The apartment was so barren she was unable to determine what kind of housekeeper Holroyd was. A small bookcase, made up of plywood strips balanced on cinderblocks. Two elderly Adirondack chairs, festooned with back issues of Old Bike Journal. An ancient motorcycle helmet on the floor, scarred and scuffed. “Is that your bike I saw chained to the lamppost?” Nora asked.

  “Yup. An old ’46 Indian Chief. Mostly.” He grinned. “Inherited a basket case from my great-uncle, and scrounged the rest of the parts here and there. You ride?”

  “My dad had an old dirt bike I used to ride around the ranch. Rode my brother’s Hog once or twice before he laid it down on Route 66.” Nora looked back toward the window. There was a row of very strange-looking plants: black, crimson, a riot of drooping stalks and pendulous flowers. Must be the only things around here that enjoy the heat, she thought.

  A small plant with dark purple flowers caught her attention. “Hey, what’s this?” she asked, reaching out curiously.

  Holroyd looked over, then dropped the mail. “Don’t touch that!” he cried. Nora jerked her hand away.

  “It’s belladonna,” Holroyd said, bending to pick up the scatter. “Deadly nightshade.”

  “You’re kidding,” Nora said. “And this?” She pointed to a neighboring plant, a small flower with exotic maroon spikes.

  “Monkshood. It contains aconitine, which is a really terrific poison. In the tray there are the three deadliest mushrooms: the Death Cap, Fool’s Mushroom, and A. virosa, the Destroying Angel. And in that pot on the sill—”

  “I get the picture.” Nora turned away from the Death Cap, its horrible mantle resembling plague-spotted skin, and gazed once again around the bare apartment. “Enemies bothering you?”

  Holroyd tossed the mail into the garbage and barked a laugh, his green eyes suddenly catching the light. “Some people collect stamps. I collect botanical poisons.”

  Nora followed him into the kitchen, a small, cramped area almost as free of furniture as the rest of the apartment. A large wooden table had been pushed up against the old refrigerator. Sitting on the table were a keyboard, a three-button mouse, and the largest monitor she had ever seen.

  Holroyd smiled at her appreciative glance. “Not a bad chunk of video real estate, is it? Just like the ones at the Lab. A few years ago Watkins bought these for all his top imaging staff. He assumes that no one who works for him has a social life. Pretty good assumption, at least as far as I’m concerned.” He glanced at her.

  Nora raised a speculative eyebrow at him. “So you do bring some homework with you, after all.”

  The smile vanished as he caught the implication. “Only declassified homework,” he replied, as he reached into a rumpled Jiffy bag and pulled out a rewriteable DVD disk. “What you asked for doesn’t exactly fit that category.”

  “Can I ask how you did it?”

  “I took the raw data from the shuttle feed this morning and burned an extra copy onto the disk. I’ve always got a handful of disks in my backpack; nobody would know the difference.” He waggled the disk and it flashed in the dim light, sending out a coruscation of color. “If you have the right clearance, stealing data isn’t difficult. It’s just that, if you get caught, the penalties are much stiffer. Much stiffer.” He grimaced.

  “I realize that,” said Nora. “Thank you, Peter.”

  He looked at her. “You knew I’d help, didn’t you? Even before you left the pizza parlor.”

  Nora returned the glance. It was true; once he’d described the way he could access the data, she felt certain he’d agree. But she did not want to hurt his pride. “I hoped you would
,” she replied. “But I wasn’t really sure until you called the next morning. And I can’t tell you how much I appreciate it.”

  Nora realized Holroyd was blushing. He quickly turned his back and opened the refrigerator door. Inside, Nora could see two cans of alcohol-free beer, some V8 juice, and a large computer CPU. Looking more closely, she noticed the computer was connected to the monitor by cables running through a small insulated hole in the back of the refrigerator.

  “Too hot out here,” Holroyd said, sliding the disk into the computer housing and closing the refrigerator door. “Put your topo over there, okay?”

  Nora began to unroll the map, then paused. “You realize this won’t be like crunching numbers all day long in an air-conditioned lab,” she said. “On a small dig like this, everybody does double or triple duty. You’d be coming along as an assistant, specializing in image sensing. Only they’re not called ‘assistants’ on archaeological digs. They’re called ‘diggers.’ For a reason.”

  Holroyd blinked at her. “What are you trying to do? Talk me out of going?”

  “I just want to make sure you know what you’re getting into.”

  “You’ve seen the books I read. I know it won’t be a picnic. That’s part of the challenge, isn’t it?” He sat down at the wooden table and pulled the keyboard toward him. “I’m risking a possible prison sentence, bringing you this data. You think I’m afraid of a little digging?”

  Nora smiled. “Point taken.” She pulled up a plastic chair. “Now how does this thing work, exactly?”

  “Radar’s just another kind of light. We shine it down on Earth from the shuttle, and it bounces back changed. The Terrestrial Imager simply takes digital photographs of what bounces back, and then combines them.” Holroyd punched some keys. There was a brief pause, then a small window opened at the bottom of the screen, displaying scrolling messages as a complex program began to boot. Several other small windows flew open in corners of the screen, displaying various software tools. Then a large window appeared at the screen’s center. Holroyd moused the cursor through several menus. Finally, an image began rolling down the large central screen, line by line, painted in artificial reds.

  “Is that it?” Nora stared at the screen in disappointment. This was the last thing she’d expected: confusing monochromatic patterns like no landscape she had ever seen.

  “It’s just the beginning. The Imager takes infrared emissions and radiometry into account, but that would take too long to explain. It also looks at the earth in three different radar bands and two polarizations. Each color represents a different band of radar, or a different polarization. I’m going to paint each color on to the screen, layering one on top of the other. This’ll take a few minutes.”

  “And then we’ll be able to see the road?”

  Holroyd gave her an amused look. “If only it were that simple. We’re going to have to beat the shit out of the data before we can see the road.” He pointed. “This red is L-Band radar. It has a wavelength of twenty-five centimeters and can penetrate five meters of dry sand. Next, I’ll add C-Band.”

  A blue color scrolled down.

  “This C-Band has a six-centimeter wavelength, and it can penetrate at most two meters. So what you see here is a little shallower.” More key taps. “And here goes X-Band. That’s three centimeters. Basically, it gives you the surface itself.”

  A neon green color rolled down the screen.

  “I don’t see how you can even begin to figure all this out,” said Nora, gazing at the distorted swaths of colors.

  “Now I’m going to paint in the polarizations. The outgoing radar beam is polarized either horizontally or vertically. Sometimes you send down a beam horizontally polarized, and it bounces back vertically polarized. That usually happens when the beam encounters a lot of vertical tree trunks.”

  Nora watched as another color was added to the screen. It was taking longer for the program to paint the image on the screen; obviously, the computational problem was becoming more complex.

  “Looks like a de Kooning,” said Nora.

  “A what?”

  Nora waved her hand. “Never mind.”

  Holroyd turned back to the screen. “What we’ve got is a composite image of the ground, from the surface to about fifteen feet deep. Now it’s a matter of canceling out some of the wavelengths and multiplying others. This is where the real artistry comes in.” Nora could hear a touch of pride in his voice.

  He began typing again, more quickly this time. Nora watched as a new window opened on the screen, lines of computer code racing as routines were added and deleted. The remote desert vastness was suddenly covered by a thin web of tracks.

  “My God!” Nora cried. “There they are! I had no idea the Anasazi—”

  “Hold on a minute,” interrupted Holroyd. “Those are modern trails.”

  “But this area isn’t supposed to have any roads.”

  Holroyd shook his head. “Some of these are probably wild horse trails, deer trails, coyote trails, mountain lion trails, maybe even four-wheel-drive tracks. There was some prospecting for uranium in this area in the fifties. Most of these tracks you wouldn’t be able to see on the ground.”

  Nora slumped back in her chair. “With all those trails, how can we ever find the Anasazi one?”

  Holroyd grinned. “Be patient. The older the road, the deeper it tends to lie. Very old roads also tend to spread through erosion and wind. The pebbles ancient travelers turned up have been smoothed over time, while new roads are covered with sharper pebbles. The sharper pebbles backscatter more strongly than the smooth ones.”

  He continued to type. “No one knows why, but sometimes dramatic things happen if you multiply the values of two wavelengths together, or divide them by each other, or cube one and take the square root of another and subtract the cosine of your mother’s age.”

  “Doesn’t sound very scientific,” said Nora.

  Holroyd grinned. “No, but it’s my favorite part. When data’s buried as deeply as this, it takes real intuition and creativity to tease it out.”

  He worked with steady determination. Every few minutes the image changed: sometimes dramatically, sometimes subtly. Once Nora asked a question, but Holroyd merely shook his head, brow furrowed. At times, all the roads vanished; Holroyd would curse, type a flurry of commands, and the roads returned.

  Time crawled by, and Holroyd grew increasingly frustrated. The sweat stood out on his brow, and his hands flew across the keys, hitting them with greater force. Nora’s back began to ache, and she found herself shifting constantly in the cheap chair, trying to find a comfortable position.

  At last, Holroyd sat back with a muttered curse. “I’ve tried all the methods, all the tricks. The data just won’t put out.”

  “What do you mean?”

  “Either I get a million roads and trails, or I get nothing.” He got up and went to the refrigerator. “Beer?”

  “Sure.” Nora glanced at the clock. It was seven, but the apartment was still insufferably hot.

  Holroyd sat down again, passing her the beer and propping a leg up on the computer table. A knobby ankle protruded from below the cuff, pale and hairless. “Is there anything unusual about the Anasazi roads? Something that might differentiate them from all these animal trails and modern stuff?”

  Nora thought for a moment, then shook her head.

  “What were the roads used for?”

  “Actually, they weren’t really roads at all.”

  Holroyd pulled his leg from the table and sat up. “What do you mean?”

  “They’re still a deep archaeological mystery. The Anasazi didn’t know about the wheel and they didn’t have any beasts of burden. They had no use for a road. So why they would take such trouble to build them has always puzzled archaeologists.”

  “Go on,” Holroyd urged.

  “Whenever archaeologists don’t understand something, they cop out by saying it served a religious purpose. That’s what they say about the roads. T
hey think they might have been spirit pathways, rather than roads for living beings to travel on. Roads to guide the spirits of the dead back to the underworld.”

  “What do these roads look like?” Holroyd took a swig of beer.

  “Not much of anything,” Nora said. “In fact, they’re almost impossible to see from the ground.”

  Holroyd looked at her expectantly. “How were they built?”

  “The roads were exactly thirty feet wide, surfaced with adobe. On the Great North Road it appears that pots were deliberately broken on the road surface to consecrate it. The roads were dotted with shrines called herraduras, but we have no idea—”

  “Wait a minute,” Holroyd interrupted. “You said they were surfaced with adobe. What exactly is adobe?”

  “Mud, basically.”

  “Imported?”

  “No, usually just the local dirt mixed with water, puddled and plastered.”

  “Too bad.” The excitement left Holroyd’s voice as quickly as it came.

  “There’s not much else. When the Great North Road was finally abandoned around 1250, it seems to have been ritually closed. The Anasazi piled brush on the road and set it on fire. They also burned all the shrines along the road. And they burned several large structures too, one of which I excavated a few years ago, called Burned Jacal. Seems it was some kind of lighthouse or signaling structure. God knows what they used it for.”

  Holroyd sat forward. “They burned brush on the road?”

  “The Great North Road, anyway. Nobody has done much research on the other roads.”

  “How much brush?”

  “A lot,” said Nora. “We found large swaths of charcoal.”

  Holroyd slammed down the beer, swivelled in his chair, and began hitting keys once again. “Charcoal—carbon—has a very specific radar signature. Even tiny amounts of it absorb radar. It has an almost nonexistent backscatter.”

  The image on the screen began to shift. “So what we’re going to look for,” he murmured, “is just the opposite of what I’ve been searching for all this time. Instead of looking for a particular reflection, we’re going to look for a shadow. A linear hole in the data.” He punched a final key.