Bolted to the side of each Voyager spacecraft is a 12-inch gold-plated copper phonograph record, sealed in an aluminum cover, etched with instructions for how to play it. Inside the grooves: greetings in 55 languages, a Georgian folk song, a kiss, the sound of a mother nursing a baby, Chuck Berry’s Johnny B. Goode, and a woman’s brainwaves recorded while she sat in a hospital thinking, among other things, about being in love. The records were engineered to remain playable for one billion years.
Voyager 1 is now almost 15 billion miles from Earth, drifting through interstellar space at roughly 38,000 miles per hour. The records are still bolted to the hulls. Nothing out there is likely to scratch them.
What is actually on the record
The full inventory, according to Smithsonian Magazine’s accounting, comes to 115 analog-encoded photographs, greetings in 55 languages, a 12-minute montage of sounds from Earth, and 90 minutes of music. Three-quarters of the disc is devoted to music. The rest is humanity trying to introduce itself in a hurry.
Carl Sagan led the team. Frank Drake handled the encoding. Ann Druyan was creative director. Jon Lomberg curated the images. Timothy Ferris, then a contributing editor at Rolling Stone, produced the audio. They argued constantly about what to include and what to leave out.
The greetings range from Akkadian, which has not been spoken aloud as a daily language for thousands of years, to a sentence in Wu Chinese. The final greeting was spoken by Nick Sagan, Carl’s six-year-old son: “Hello from the children of planet Earth.”
The brainwaves
The strangest item on the record is also the most intimate. Druyan suggested recording a person’s brainwaves and compressing them into audio, on the theory that a civilization advanced enough to retrieve the spacecraft might also be advanced enough to decode the thoughts of the person being scanned. She volunteered.
Druyan was hooked to an EEG. She had prepared a list of subjects to meditate on: the history of Earth, the rise of civilization, the problems faced by a technological society. She had also, days earlier, gotten engaged to Carl Sagan. In Murmurs of Earth, the 1978 book the team wrote about the project, Druyan acknowledged that her personal circumstances at the time influenced the recording.
Compressed into a brief segment, Druyan later described the brainwaves as sounding chaotic and energetic. Somewhere in that recording, traveling now past the heliopause, is the neurological signature of a woman thinking about a man she had just agreed to marry.
The kiss, the whale, the baby
The sound montage is twelve minutes long and contains things you would never think to record on purpose. Wind. Rain. Surf. A horse and cart. A Saturn V launch. Morse code. A chimpanzee. The first cry of a newborn. A mother and child. Footsteps. Heartbeat. Laughter.
The kiss took multiple attempts. Several were rejected as too quiet, too theatrical, or insufficiently sincere. The music producer Jimmy Iovine, then at the start of his career, tried kissing his own arm. The one that made it onto the record is a kiss that Ferris and Druyan worked together to capture.
The whale song came from the biologist Roger Payne, who had captured it with hydrophones off Bermuda in 1970. Payne, who captured the whale song with hydrophones off Bermuda in 1970, believed it was the ideal recording to include. Ferris layered the song quietly behind the spoken greetings so that an alien decoder, if curious, could extract it. The bandwidth, he noted, accommodated both.
How a record survives a billion years
The physical object is a copper disc plated in gold. The cover is aluminum, electroplated with a sample of uranium-238 whose half-life of 4.5 billion years gives any finder a way to date the launch. The disc plays at 16 2/3 revolutions per minute, half the speed of a normal LP, to fit more material. A ceramic cartridge and a stylus are included, along with diagrams showing how to use them.
Out in interstellar space there is no oxygen, almost no dust, and very little radiation of the kind that degrades organic material. The main threat is micrometeoroid impact, which is extraordinarily rare in the volumes the Voyagers are crossing. NASA’s engineers calculated a useful life of one billion years for the recording itself.
Modeling the spacecraft’s long-term trajectory suggests the Voyagers will not pass within a light-year of any star for at least the next several hundred thousand years and could continue drifting essentially intact for trillions of years without coming remotely close to any stars. The record, in other words, will outlast the Sun. It will outlast the solar system. It will, by current estimates, outlast most of the galaxies visible from Earth tonight.
Why 55 languages
The 55 greetings were chosen from among speakers available at Cornell University and through a network of contacts Sagan and Druyan reached through Cornell’s language department. The wording of each greeting was left to the speaker.
The greetings vary from simple phrases of friendship to more elaborate welcomes. There is one in Sumerian and one in Akkadian, both languages that have been dead for thousands of years.
The music
Ninety minutes of music had to represent the entire planet. Ferris, who produced the audio, has said there were a thousand worthy candidates for every track that made it on. Bach, Beethoven, and Mozart are represented. There is Navajo night chant, a Bulgarian shepherdess song, an Aboriginal Australian song, a Peruvian wedding song, Indian raga, Azerbaijani balaban, Solomon Islands panpipes, and a Pygmy girls’ initiation song from Zaire.
And there is Chuck Berry’s Johnny B. Goode. According to Ferris, Sagan had to warm to the idea. The folklorist Alan Lomax objected. Sagan’s reply, as Ferris remembered it, emphasized that rock music was popular among young people worldwide.
After the second Voyager launched, Saturday Night Live ran a sketch featuring Steve Martin and a joke about the aliens’ response to Chuck Berry.
What the team chose not to include
There is no war on the record. No images of weapons, no photographs of conflict, no political boundaries. The committee discussed this and concluded that a friendly greeting should not arrive with evidence of hostility. There is also no religion. No churches, no mosques, no temples shown as religious sites, no scripture. The Taj Mahal was included not as a religious building but because Shah Jahan built it in honor of his wife rather than a god.
NASA vetoed one image: a nude photograph of a man and a pregnant woman holding hands. The compromise was a silhouette diagram showing the fetus inside the womb. The agency had been criticized for the nude figures on the Pioneer plaques five years earlier and was not eager to repeat the conversation.
Where the records are now
Voyager 1 crossed into interstellar space in August 2012, becoming the first human-made object to do so. Voyager 2 followed in November 2018. Both spacecraft are still transmitting science data, though their power supplies are dwindling and engineers at JPL are shutting off instruments one by one to keep the radio alive. The signal from Voyager 1 now takes more than 23 hours to reach Earth, traveling at the speed of light.
The records themselves do not require power. They will keep working long after the transmitters fall silent, long after the plutonium decays past usefulness, long after the spacecraft become inert metal coasting through the dark.
The longest message ever sent
Most of what humans have made will be gone within a few thousand years. Concrete crumbles. Steel rusts. Plastic photodegrades. The pyramids are expected to erode within a hundred thousand years. The Library of Congress, in its current physical form, will not survive a million.
The Voyager records are the longest-lasting human artifacts ever produced, and there is no obvious successor. NASA approached Ferris about producing another record decades ago. He declined, saying it was better to let someone else take a shot. Although the original masters have since been reissued for collectors on Earth, no subsequent deep-space mission carries anything comparable.
The Voyager mission raises questions about what legacy means over vast spans of time, and the records sit oddly inside that question. They were built for an audience that may not exist, encoded in a format that may never be played, addressed to a finder who will, by the time they arrive, have no way of knowing whether the species that made them still exists.
Carl Sagan, who did not believe in an afterlife, believed that human legacy lives on through the impact individuals have on others. The brainwaves on the record belong to the woman he married three years after Voyager 2 left the launch pad. They are still out there, still traveling, still encoded in the grooves of a copper disc plated in gold, drifting somewhere past the edge of everything the Sun touches, at 16 and two-thirds revolutions per minute, for the next billion years.
