Spiral (7 page)

4

TWO HUNDRED STUDENTS WERE PACKED INTO SCHWARTZ AUDITORIUM
for the nine a.m. lecture of Physics 1205, “Physics for Presidents.” Jake Sterling was twenty minutes into the lecture. He’d gotten off to a slow start—the long night before had seen too much honesty, and the subsequent three a.m. end of a four-month relationship—but now he was hitting his stride.

The premise of “Physics for Presidents” was simple: assume your audience was composed of future presidents of the United States. You have them for one semester. What lessons would be of optimal utility? Jake’s answer was simple: he taught them the rules of the world. What could and could not happen. We could build a nuclear submarine but not a nuclear airplane. There was enough sunlight to power the United States by solar, but only if we carpeted a good chunk of Nevada with solar cells. His was an Army man’s approach, a presentation of options. Jake hadn’t worn the uniform for well over a decade, but he still had the no-nonsense attitude of a soldier.

“Isaac Newton was the tipping point—a solitary man standing at the transition between the ancient world and the modern. Before Newton, we were a civilization of superstitious craftsmen. We could make plows and crossbows and trebuchets, but our understanding of the world—and our ability to control it—was something that we learned by experience, by trial and error. Or we were guided by ‘experts’ that had a line to a deeper truth. Religious leaders. Shamans. People who spent their lives waiting for the gods to reveal the mysterious forces at work in the universe. But no more. After Newton, you just sat down with pencil and paper and worked it all out. No magic. No mumbo jumbo. And no special training required, except a decent knowledge of mathematics.”

Jake had taught this course three semesters in a row, a record for him in the eight years he’d been at Cornell. He typically switched teaching assignments as often as he could, preferring to wander the entire curriculum instead of digging deeper and deeper into the same hole. But he loved this course. His colleagues in other departments made noise about how art, politics, or the pen was a hammer to shape the world, but in Jake’s estimation, technology was the biggest hammer out there.

Jake continued. “People wasted little time putting Newton’s laws, and those of Maxwell, Einstein, and Schrödinger, to productive use. And since we had laws for everything, no matter how big or small, they allowed us to move beyond everyday human scales. The first great push was toward the ever bigger: mighty dams, great oceangoing vessels, and—perhaps the high-water mark of the big—venturing to the moon. Now we are in a second revolution. Question: what is it?”

The students looked bored. Their indifference surprised him. The discovery that the natural world was mathematically explicable was, to Jake, the single most significant development in the history of humanity. From this followed the obvious consequence: the world was controllable. The constituents of the world—radio waves, apples, or planets—did what the differential equations told them to do. You learn to perform some formal manipulations of symbols on a page, and the next thing you know, you’re building radios that can communicate across oceans, or launching projectiles at your enemies with a precision that was terrifying to behold. It was that simple.

“What is it?” he repeated. “No guesses?”

“Nano,” came an answer from the front.

“You got it. Nano. The realm of the ultrasmall. Small has replaced big as the terra incognita for techno-explorers. The nanoworld is the new frontier.”

Jake clicked an icon on his computer and a color photo of an Intel Core 2 Quad processor chip appeared on the ten-foot-tall screen behind him. “A modern integrated circuit is the most complex and sophisticated piece of technology ever made,” Jake said. He clicked again, and the view zoomed onto a single transistor within the circuit. “This transistor is a thousand times narrower than a human hair. It is as much smaller than you as the earth is bigger than you. Distances in this world are measured in nanometers. Nano—from the Greek
nanos
, meaning ‘little old man,’ indicating one billionth. That’s small. One billionth of the population of the earth wouldn’t even fill up the front row of this class.

“The power of nano makes it possible to construct an entire world in the space of a meter,” Jake continued, as the image on the screen zoomed back out, the single transistor quickly lost in the rectangular maze of transistors, capacitors, and copper interconnects. “This computer chip is a world of doors and passageways for electrons, guiding them in a dance as intricate and involved as the daily movements of millions of people in any major city. An entire city for electrons can be built in a space smaller than a postage stamp.” The image faded and was replaced by an aerial view of the gridlike streets of Midtown Manhattan. “A circuit as complex as Manhattan could fit on the tip of my finger,” he said. “And unlike a real city, there are no traffic jams, no gridlock. All of it works flawlessly. Not a single packet of electrons out of place.

“In a computer chip, time is also miniaturized. Your computer can do operations—multiply two numbers, or communicate with its neighbors—about once every nanosecond. A one-gigahertz processor makes roughly a billion computations a second. Think about it. A billion in one second. You only live for, at most, three billion seconds. In only three ticks of the clock, a computer has as many thoughts as you will have in your whole life.” Jake stopped to let that sink in. “So every three seconds, your computer is like the entire population of Manhattan living a lifetime. And people wonder why it takes so long to boot up.”

A few laughs rippled through the students.

“Miniaturization was the most revolutionary force in the second half of the twentieth century. From Bill Gates to Gordon Moore, empires have been made constructing and controlling tiny electron cities that have lifetimes of thoughts in seconds. Computers, in effect, miniaturized our thoughts. But humans do more than think. What else do we do?”

“Sleep,” someone called from the back. More laughs.

“True enough. What else?”

“Move. We walk around.”

“Right. We walk. But walking is a pretty sophisticated form of locomotion. Let’s start with something simpler. What about crawling, for example? Can we make machines that crawl?

“Let me introduce a couple of my graduate students,” Jake said. He waved, and they came up on stage. “This is Joe Xu and Dave Gruber. They’ve got something to show you.”

Jake kept going while Dave and Joe set up. “How many of you have heard of DARPA?”

A few hands went up.

“DARPA stands for Defense Advanced Research Projects Agency. It’s a kind of military venture-capital firm—always on the lookout for the Next Big Thing. The Internet, the global positioning system, and the Predator Unmanned Aerial Vehicle, those were all DARPA projects. Most sink like a stone, but those that succeed can change the world.

“In 2004, DARPA hit upon a new way to drive innovation: the DARPA Grand Challenge competitions. These are open competitions where DARPA sets a goal and teams of scientists and engineers from around the country try and tackle it. The first one was to create a car that could navigate a desert racecourse without a driver. First prize was two million dollars. In 2004, nobody succeeded. In 2005, five crossed the finish line. By 2007, the challenge had moved from the desert to city streets, and people are now seriously talking about driverless cars on America’s highways. The lesson was clear: you throw money and talent at a problem, spice it up with a little head-to-head battle, and it’s incredible how fast innovation can happen.

“For their next competition, DARPA went small,” Jake continued. “The Grand MicroChallenge was to develop a robot smaller than a dime that could survive on its own in a woodland environment, without external guidance or power, for a month. The ‘woods’ consisted of a giant terrarium DARPA set up in a storage hangar at Fort Belvoir, near Mount Vernon in Virginia. The first year was a bust. Nobody got close, including our team. All the entrants ran out of juice long before the month was out. But the next year, with Liam Connor’s help, we won it running away.” This got their attention. Liam was a legend—the old man’s wrinkled face was easily the most recognized on campus.

Joe and Dave were nearly ready, and Jake retreated to the edge of the stage. Joe, whose real name was Xinjian, was a classic physics grad student, tall and thin, with wide eyes and a love for detail. He was in his fifth year, finishing his thesis on the mechanics of micro-robot locomotion. He already had an offer for a permanent position in Hong Kong but was holding out for a Millikan Fellowship at Caltech. Gruber was a little more unusual, a third-year muscular fireplug with a flair for public speaking—he’d done some acting as an undergraduate at Yale. Each had their part down pat: Dave handled the audience, and Joe handled the Crawlers.

Joe sat at the microscope set up on the corner of the stage. The scope’s video camera was hooked up to the overhead projector. Joe flipped a switch, and several in the class gasped. A giant creature appeared on the screen: a robotic spider-monster. It scurried to the left, then stopped, turned one hundred and eighty degrees on its six legs, and took off in the opposite direction.

“Say hello to a MicroCrawler,” Dave said. “Arguably the most advanced miniature robot in the world. And don’t worry, it won’t hurt you. The image is magnified a thousand times. It has jointed silicon legs that propel it forward, and a small microprocessor in its body that controls its movement. This one here is our smallest—about the size of a mustard seed. We have models ranging up to the size of a quarter. We build them at the Cornell Nanofabrication Facility using the same patterning, depositing, and sculpting techniques people normally use to make computer chips.”

Jake watched as the students stared at the Crawler, rapt. He smiled at Dave and Joe—the three of them had been through this routine dozens of times, but the spark hadn’t faded. Jake was proud of them. Jake had designed the Crawlers and oversaw the project, but Dave and Joe had done most of the painstaking detail work needed to make the designs a reality. Thousands of hours of struggle, failure, and more struggle. The three of them had gone through years of engineering, design, tweaking, and redesign in creating these little beasts. Doing something that had never been done before was brutally hard, like assembling a model ship in the dark. Make that a ship in a
very small bottle
in the dark. But they had done it. And—the glory of technology—done once, it could be done again, by anyone, anywhere. All you needed were the fabrication recipes and the right tools.

Joe adjusted the microscope’s optics, zooming out so the students could see the entire petri dish that corralled the tiny robots. Ten Crawlers scurried around while dozens more lay motionless, littering the miniature landscape. One hopped in a tight circle, like a fly with a wounded wing.

“What’s wrong with that one?” a student in front asked.

Joe said, “On this batch, we had a bad liftoff during step twenty. When we put down the piezo actuators.”

“Step
twenty
?”

“It takes forty-seven separate fabrication steps to make a Crawler,” Dave said. “Forty-nine for ones with a full communications system. It rivals Intel’s most complex computer chip. Five weeks of twelve-hour days to get through the entire process, assuming nothing goes wrong.”

“And something always goes wrong,” Joe added with a pained laugh. “It’s like walking a tightrope. Each step must be perfect. Make one little mistake, it’s all over.” He picked up a pair of tweezers and guided them toward the tiny creatures, the tips appearing enormous in the microscope’s field of view. He carefully brushed away the dead Crawlers until only the scurriers and the circler remained. “Let’s put you out of your misery,” Joe said as he grabbed the circler with the forceps. He applied pressure, and its body shattered into a hundred pieces. The students cringed.

A student in the second row raised his hand. Dave called on him.

“They seem like they’re looking for something.”

“They are.”

“What?”