MARJOLIJN DUIJVESTEIN

Caduceus

“I GOT THE tattoo when I received my medical degree,” writes Marjolijn Duijvestein, a resident at the Leiden University Medical Center in the Netherlands.

On their crisp white coats, doctors carry a badge borne of magic and monsters. Across ancient Greece, temples were built to the god Asclepius, the god of medicine. He may have started out as a real doctor, but as his followers grew, he received a divine make-over. Now he was the son of Apollo—appropriately so, since the sun god was also the doctor of Olympus. The mother of Asclepius was a nymph named Coronis. When Apollo discovered she had another lover, he killed her with his bow and arrow and had her laid on a funeral pyre. At the last minute he was filled with remorse, and opened her belly to save his child. The name Asclepius means “cut-open.”

The centaur Chiron raised Asclepius and tutored him in medicine. The snakes of Mount Pelion, Chiron’s home, taught Asclepius which herbs could heal the sick. Asclepius himself became the most famous doctor of his time, thanks to the help of the snakes, who accompanied him wherever he went. In statues and on coins, Asclepius was pictured walking to visit his patients with a snake wound around his staff. Eventually Asclepius became so successful that Hades complained to Zeus that the doctor was cutting off the flow of the dead to the underworld. Once Asclepius started actually raising the dead back to life, Zeus decided things had gotten out of hand: he killed Asclepius with a lightning bolt.

After his death, the stories went, the doctor became a god. His priests reared live snakes that swarmed around the grounds of his temples. Generations of Greek doctors, including Hippocrates, claimed to be the direct descendants of Asclepius. Romans believed that he took the form of a snake to come to their rescue during epidemics.

In the Renaissance, European doctors revived the image of Asclepius’s staff as a symbol of medicine. Around 1900, American doctors confused this legacy by adopting a symbol of two snakes wrapped around a staff with wings. This is the caduceus, which the winged messenger of the gods, Hermes, carried with him when delivering news to Zeus. Thus, American doctors may have seen the caduceus as a publisher’s symbol in some medical books of the time and mixed it up with Asclepius’s single snake. In 1902, the two-snake caduceus was adopted by the U.S. Army Medical Corps, and the confusion was frozen in place. But today Asclepius’s rod can be found on the logo of the World Health Organization and the American Medical Association. In an age when we can take antibiotics to cure once fatal infections, when organs can be moved from person to person, when robots scour out clogged blood vessels like sink pipes, the symbol should remind us of the original doctor, who incurred the wrath of the gods with his power.

SHI-HSIA HWA

Vaccine Tree

“I’M A VIROLOGIST in a biotech company in Singapore,” writes Shi-Hsia Hwa. “Here’s my story: I’ve been interested in infectious diseases since I was a kid because my father almost died of TB when he was an infant, and his secretary was an older man with a pronounced limp from polio. I must have been the only kid who looked forward to mass vaccination days in school. For a field trip to the Philippines after my bachelor’s and my first job shortly thereafter, I had to be immunized against a lot of other things that the average person doesn’t.

“The choice of motif was inspired by a verse from the biblical book of Revelation (a.k.a. Apocalypse): ‘On each side of the river stood the tree of life, bearing twelve crops of fruit, yielding its fruit every month. And the leaves of the tree are for the healing of the nations.’ The ‘tree of life’ motif in Western folk art is a tree bearing various different fruits on its branches. I was stupid and didn’t check the stencil after the tattooist smudged one part, which is why there are two PVs; one should have been HAV for Hepatitis A. Like everybody else in this part of the world, I’ve had the BCG but will not add a TBa fruit until a truly effective tuberculosis vaccine is invented.”

Target

“I DIDN’T TATTOO SCIENCE—science tattooed me!” writes Frank Turnitza. After Turnitza was diagnosed with testicular cancer, his doctors decided to treat the tumor with beams of radiation. To aim one of the beams correctly, they gave him this tiny tattoo on his abdomen. The cancer is gone, but the mark of science remains.

FRANK TURNITZA

Biotech

“THE BLUE ATOMIC symbol for science, the black biotech is for, well, biotech, and the flower is my home state’s flower, the alaskan forget-me-not, which also symbolizes life,” writes Cheri Cloninger, who works in, well, biotechnology.

CHERI CLONINGER

EKG

A CARDIOLOGIST, LIAM YORE, wears two electrocardiogram readouts. The first, on the inside of his left forearm, shows a wave of electricity during a heartbeat lagging on its way from one chamber of the heart to the next. Called second degree AV block, Mobitz I /Wenckebach, it is actually a benign condition. Such is not the case for the second read-out, on his upper forearm, which shows recordings from three separate EKG leads. It shows an acute inferior myocardial infarction—a heart attack, in other words.

LIAM YORE

Noise Circuit

“MY COLLEGE EXPERIENCE working towards my electrical engineering degree was a long and difficult one,” writes Cassie Backus. “Everyone can admit that their early twenties are a difficult time anyway, what with growing and changing and maturing, but adding engineering school to the mix surely upped the challenge. I nearly dropped out several times during my college career, worried that I was condemning my life to one of solitude doing design at a desk in some dimly-lit cubicle farm. I have since used my degree to secure a role doing application engineering for a technical company that handles human interface solutions, and I couldn’t be happier about it. When I eventually finished my degree after five years, I wanted a tattoo to mark my progress in life.”

CASSIE BACKUS

Electrical engineering has its own alphabet: a set of symbols for different elements that can be arranged into circuits. Just as there is no end to the poems a poet can write with the English language, there is no end of devices electrical engineers can invent. And rather than photograph their creations, or try to describe them in words, engineers can simply draw capacitors, transistors, and the other tools of their trade.

Backus chose for her tattoo a schematic diagram of a noise circuit. The current that flows through electronics never perfectly matches its diagram, thanks to random fluctuations. Electrical engineers therefore build in elements that can filter out the noise and strengthen the signal. “To me, this tattoo says ‘I am responsible for the creation and the resolution of static in my life,’” writes Backus.

Voltage

“THIS TATTOO IS the schematic for the reference point of electricity,” writes Konstantin Avdashchenko, an electrical engineer. “It’s really either the point at which you consider voltage to be 0, or, in this picture’s case, the physical connection to the earth (hence the lower calf).”

KONSTANTIN AVDASHCHENKO

“Mein Gott im Himmel!”

TYLER ROLLINS, a musician, wears the drawing that accompanied a patent granted to Thomas Edison on February 19, 1878. “I think that this invention goes mostly under-appreciated,” writes Rollins. “This was the first phonograph! The first thing that could record and playback sounds, voices, music!”

I usually don’t care for exclamation points, but Edison’s invention certainly deserves a few. If you put yourself back in 1878, it’s hard to imagine how an aria could be engraved on a piece of tinfoil—not the words, but the sounds of the words—captured and forever ready to sing again on command.

The phonograph got its start as a glorified telegraph. Edison experimented with devices that could record the dots and dashes of a telegraph message on a piece of paper. The paper could then be fed back into a telegraph machine to send out the message automatically. When the strip of paper was fed quickly under a contact lever, the lever rattled up and down noisily. That noise made Edison think about the nature of sound—a series of vibrations of different frequencies and amplitudes. He had been trying to improve the telephone, and had discovered that a diaphragm made of a sandwiched layer of carbon trembled with great sensitivity under the onslaught of a voice. Perhaps, he thought, the force of that quivering could drive a sharp point into a piece of paper, deeply or shallowly depending on the sound at the moment. And if he ran another point rigged up to another diaphragm, he could hear the same sound again.

Edison eventually decided that tinfoil wrapped around a spinning cylinder would work best. He had John Kreusi, a German workman in his shop, put the device together. When Kreusi was nearly done, he asked Edison what it was for.

“I told him I was going to record talking, and then have the machine talk back,” Edison later wrote. “He thought it absurd.”

Edison recited “Mary Had a Little Lamb” into the phonograph, and a moment later, the machine was playing back the rhyme. It must have sounded strange—clouded with static, twisted so that a thirty-year-old inventor sounded like a great-great-grandfather. Nevertheless, it was obviously Edison’s own voice. Kreusi muttered, “Mein Gott im Himmel!” And even Edison was impressed. “I was never so taken aback in my life,” he wrote.

The waves of shock radiated out of Edison’s New Jersey workshop. He went to New York, walked into the office of Scientific American, and informed the editor that he had something to show him. He unpacked the phonograph and recorded “Mary Had a Little Lamb” once more. The staff had him record it again, and again. More people came into the office to see it. Finally he had to stop because the editor was worried the floor would collapse from the weight of the astonished.

Edison went back to his lab in Menlo Park, and special trains were run from New York so that crowds could come listen to him play his voice to them. He ended up playing the phonograph for President Rutherford Hayes in the White House until past three in the morning. John Heyl Vincent, a prominent theologian of the day, came one morning to the lab and skeptically asked Edison if he could speak a few words into it. “He commenced to recite biblical names with immense rapidity,” Edison later wrote. “On reproducing it, he said: ‘I am satisfied, now. There isn’t a man in the United States who could recite those names with the same rapidity.”

TYLER ROLLINS

Tinfoil gave way to wax and cylinders gave way to disks of resin. Engineers found ways to impress sound onto magnetic tapes, onto films, and then onto plastic compact disks, hard disks, and flash memory. Instead of the rich rise and fall of analog sound, we now listen to the infinitesimal staccato of digital recordings. Telephones have merged into this digital stream, our voices and our music engraved into an abstract ocean of ones and zeroes. We swim in this engraved sound, which flows out of car radios and mobile phones, televisions, digital pianos, and talking dolls. And it all began with the drawing on Rollins’s arm.

Tesla Motor

“MY FASCINATION WITH Nikola Tesla started in elementary school, when my science teacher compared Tesla and Edison,” writes Abraham Orozco, the science director at Heart of Los Angeles, a community center for children. “I decided to pay my tribute to the wizard with a patent drawing on an electric magnetic motor, submitted by Tesla in the late 1800s.”

Edison was a factory of a man, churning out one invention after another with a methodical steadiness. No one ever mistook him for a wizard. But an aura of magic enveloped Edison’s great rival, the Croatian-born engineer, Nikola Tesla. Tesla worked briefly for Edison when he came to the United States in 1884, but the two had a falling out over money. Perhaps Edison sensed a threat even then. Edison wanted to power the world on direct current, but instead, Tesla went on to develop motors, lights, and other devices that could run on alternating current. In 1893, President Grover Cleveland came to the Chicago World’s Fair, where he pressed a button and switched on a hundred thousand lamps running on Tesla’s alternating current.

To a great extent, we now live in Tesla’s world. And yet Tesla was never quite of this world. With the money he made from his early inventions, he opened laboratories where he could explore the ragged edges of engineering. He was in love with action at a distance. He invented coils that could pick up faint radio signals and make them loud enough to be heard. He built boats he could control by remote control. He could light up a vacuum tube without a single wire.

ABRAHAM OROZCO

Tesla built a tower on Long Island where he hoped to send wireless messages and power homes miles away. He dreamed of a world where a businessman could dictate a memo in New York and have it show up instantly in London. A watch-sized device could let him listen to a sermon, a song, or a speech anywhere on Earth. Most of his dreams ended in bankruptcy, and Tesla ended his life in a two-room apartment in New York. A picture of a Telsa invention is not merely a plan for a motor or a vacuum tube. It’s the image of an electrical utopia.

Crystal Radio

THOMAS AREY, a technical writer, wears a schematic diagram for a basic crystal radio. As the nineteenth century came to an end, engineers like Nikola Tesla and Guglielmo Marconi developed the technology that could transmit Morse code not by wires, but through the air, riding atop radio waves. Further developments allowed radio stations to broadcast voices and even music. But initially, listening to radio was a rare luxury, mostly limited to ship-to-shore operators. To pick up a radio transmission, you needed an antenna to catch the signal and convert it into alternating current. Then you needed a way to turn the current in your radio into something you could hear. The machinery required for this transformation was too complex and expensive for the masses.

THOMAS AREY

Radio’s first great liberation came in 1906, when an American engineer named Greenleaf Pickard ran radio waves through minerals. He found that the waves could travel in one direction through the crystal structure of some minerals, but not the other. This fussiness, Pickard realized, could allow a mineral crystal to become the heart of a simple radio. An antenna would simply need to capture a signal and deliver it through a fine wire to the crystal. Instead of the peaks and troughs of an alternating current, only the peaks came out the crystal. These pulses of direct current could rattle the diaphragms in a pair of headphones, creating sound.

Crystal radios were a titanic hit as soon as Pickard started selling them, despite the fact that they quickly became obsolete. They could only pick up radio broadcasts from a couple dozens miles away. Newer radios, with vacuum tubes and other technology, could pick up more distant signals, and they could even produce sound through speakers loud enough to fill a room.

Instead of heading for the dust heap of technological history, however, crystal radios became an underground sensation. Fancier radios needed a supply of electricity, but crystal sets needed nothing. They simply hummed in sympathy with the vibrations of the world. The parts for a crystal set were few and cheap. Boy’s Life ran ads for crystal set kits. People could use a metal bedpost as a ground. In World War II, American soldiers were often barred from owning regular radios, for fear the enemy would detect the oscillators inside them. So soldiers built “foxhole radios,” using mortar fragments, razor blades, pencil points, and other items they could scrounge.

Today, when we get our radios from a complex network of satellites and computers, it’s still refreshing to assemble a crystal radio kit. Even the schematic diagram of a crystal radio on a shoulder is bracing in its simplicity. It says: this is all it took for our wireless world to be born.

Microwave

MICROWAVE ENGINEER Chris Sanabria wears an engineering icon, known as the Smith Chart. It is the most useful thing that came out of a magnificent folly that consumed Bell Labs in the late 1920s. Bell Lab engineers were looking for new ways for people in the United States to communicate with Europe. One idea they tried out was using short-wave radio. In Lawrenceville, New Jersey, the engineers went to ludicrous extremes building curtainshaped antennae that sat atop twenty-six steel towers, stretched out across a mile of countryside.

One of the engineers, Philip Smith, had to make the array actually work. The biggest trouble he encountered lay in the transmission lines from the radio transmitter to the antenna. Because the radio waves had such a high frequency, they could simply radiate away from the cables. And when they encountered a new part of the system, some of the waves were reflected backwards instead of continuing on. To compensate, Smith had to build in circuits that could preserve the signal. He had to make lots of rapid-fire calculations to set the radio waves right again. A longtime fan of the slide rule, Smith realized that he could trace out the different variables that he had to calculate onto a curved grid. He could then move from one intersection to another on the chart until he ended up at a spot that would give him the answer he needed. Smith published an article describing his chart, and soon it was spreading among engineering circles, bearing his name. Bell Labs abandoned the shortwave project in the early 1930s. Today, engineers can use computers to solve the same kinds of problems. But the Smith Chart survives. For one thing, it’s convenient and easy for engineers to use. And for another, it has an inadvertent beauty.

CHRIS SANABRIA

Apple

CHRISTOF KOCH is the chief scientific officer at the Allen Brain Institute, where he oversees an ambitious attempt to map every neuron involved in behaviors, such as seeing and hearing. “The original Apple Macintosh, together with the Boeing B-747 Jumbo Jet and the Golden Gate Bridge in San Francisco, are the three most beautiful and elegant artifacts of the twentieth century,” Koch writes. “A perfect marriage of form and function.”

CHRISTOF KOCH

RFID

PEOPLE WHO SEE Paul Johanson’s tattoo often don’t recognize the image. And when he explains that it’s an RFID tag, their blank stare does not disappear. Johanson has taken to carrying a real RFID tag in his wallet, which he takes out as he explains what it is. It’s ironic that RIFD tags remain so obscure, even as they surround us, silently singing our most intimate details.

RFID is short for radio frequency identification. The basic design of a tag is simple. It contains miniature antenna for picking up a distinctive signal, along with circuits for producing a signal of its own. At their simplest, RFID tags are like crystal radios: they don’t even need a power source, because they can harness the energy of the incoming radio waves. Fancier tags have their own batteries, which allow them to do more complicated signal processing and detect more distant signals.

RFID tags are so small and cheap that businesses can slip them into every package they ship to track their whereabouts. Dogs and cats are “chipped” by vets so they can be identified should they become lost. RFID tags sit in millions of cars, allowing people to pay for tolls simply by driving through a toll booth. In many countries, commuters use RFID-tagged cards to board buses and trains. Casinos implant them in high-priced poker chips. They lurk in passports. Police badges contain RFID tags, to foil counterfeiters. Surgeons slip them into sponges, so that if they lose one in a patient’s gut, a pass of a wand over the stomach will identify it.

It’s also possible—even legal—to implant RFID tags permanently in people. A company called Verichip has designed an RFID tag that can be implanted in diabetics, where it can measure vital statistics and coordinate the various medical devices and catheters. People suffering from dementia could be implanted with a tag so that police who pick them up would know exactly where they belong. And it’s possible that society will gradually slide towards ubiquitous chipping—a prospect that terrifies civil liberties watchdogs. But even without surgery, RFID tags are now rife within the body politic. With the right equipment, a thief can snatch all sorts of valuable information from passersby. Their blank stare is no protection.

PAUL JOHANSON

Satellite

“I AM AN AEROSPACE engineer who has worked in the field of microsatellites for the last 20 years,” writes Terrance Yee. He wears tattoos of some of the satellites he has helped build. His first tattoo was CHIPSat, which the University of California at Berkeley used to scan for faint traces of the cloud from which our solar system formed. The TacSat-2 spacecraft (opposite page), launched in 2006, was built for the Air Force to develop technology for taking battleground images. Next came the DSX spacecraft (right), which travels around the Earth in an oval-like orbit that takes it through belts of intense radiation that surround our planet. The satellite is equipped with devices that can remove radiation, which might be used to protect satellite from nuclear attacks.

“Small satellite missions are very demanding,” writes Yee, “requiring total dedication to the mission and getting the job done on a tight budget and short schedule with really challenging new technology. In order to lead teams through this sort of development, you have to be 100% committed and very passionate about your endeavor. It can’t be just a job, but a calling, something that you recognize only a handful of people in the world are lucky enough to do. I’m inspired by the work I do and I hope the artwork I have inspires others to be as passionate as I am about space.”

TERRANCE YEE

NOAH RADFORD

HEATHER WILKINSON

Pioneer & Voyager

IN THE EARLY nineteenth century astronomers and other scholars began to think seriously about communicating with aliens. At the time, many of them were convinced that aliens were close by, living on the Moon. To send a message to the lunarians, some proposed digging trenches across the Sahara, filling them with kerosene, and lighting them ablaze. The great mathematician Karl Friedrich Gauss favored clearing vast tracts of Siberian forests to create a gargantuan piece of geometry—a textbook figure of the Pythagorean theorem, perhaps. By the end of the nineteenth century, lunarians had evaporated into myth, but in 1920, Robert Goddard, the inventor of the rocket, was still arguing for humanity to compose messages for aliens. Instead of the Moon, however, he turned his attention to Mars. He urged that spacecraft should be sent to Mars, engraved with figures that Martians might recognize.

In 1973, the dream of Gauss and Goddard became real. The Pioneer 10 probe was launched into space bearing a message for aliens. A gold plaque depicted a naked man and a woman, along with a celestial map.

The map shows the location of Earth relative to nearby pulsars, which are rapidly rotating stars that unleash regular pulses of radiation “The intervals are very much like fingerprints and are distinct from pulsar to pulsar,” explains Alaina Hunt, an artist and amateur astronomer (see Alaina Hunt). “On the map, each pulsar’s period is encoded in binary code. To decipher the period in megahertz, one needs to figure out the binary number then multiply it by 1420 MHz to get the period of each of the pulsars. With the knowledge of relative distance and the pulsars’ periods, one can triangulate the position of our sun.”

Pioneer 11, launched the following year, bore the same plaque. Both space probes have left the solar system and are now hurtling into deep space. Once NASA had finished with the Pioneer probes, they designed a new generation of spacecraft, called Voyager (see Heather Wilkinson). Launched in 1977, it carried a new plaque. It included not only engravings, but was also etched with a phonographic recording of music, natural sounds, and digitally encoded images (see Noah Radford).

I like to think of these engravings as the ultimate science tattoos. It would be presumptuous to think that aliens will ever see them, though. Voyager has followed Pioneer out of our solar system, where the probes will be spending thousands of years far from another star. We can only hope that an alien civilization will be able to detect tiny spacecraft far from their own planets, adrift in a great void. Even if aliens did scoop up one of our probes, we cannot assume they’d be able to figure out the meaning of their tattoos. It can be hard enough to figure out a science tattoo here on Earth without some help from its owner.

What we do know is that these plaques will escape the fate of every human creation here on Earth. While the pyramids of Egypt and the Empire State Building crumble under the relentless force of wind and rain and rust, the Pioneer and Voyager plaques will last for hundreds of millions of years. They may well become the final traces of our species. They are not a gesture to aliens, then, but to the unimaginable future.

NILES INGALLS

ALAINA HUNT

ANDY GRACIE