A golden voyage

Forty years ago we launched the Voyager spacecraft. Now over 20 billion km from Earth, Voyager holds the golden record: our message in a bottle to any E.T. who would find it.

Illustration by Ben Coy

Illustration by Ben Coy

One evening at my parents home in Hawaii, I sat on the deck overlooking the sea and watched the sun set. The sky was a vibrant symphony, each cloud an instrument lighting up in time with the conductor’s baton. I sat enchanted until the sun sank below the horizon and the mosquitos became unbearable. This particular display moved me deeply and prompted me to wonder if this experience is solely reserved for the lucky inhabitants of Earth.

Is there perhaps another terrestrial planet out there in a distant galaxy where another being observes a similar phenomenon of light from its star filtering through the atmosphere? What if this being didn’t have comparable sensory organs to receive and interpret light in the visual spectrum, how would you describe a sunset to them? It can be difficult to communicate with another human who speaks another language or has different political views, let alone with a being from a planet orbiting a distant star.

Trying to find the words to describe our home in space — jumping into the ocean on a summer day, petting a purring cat, looking up at a mountain 20 times larger than you, falling in love, or the colour blue — feels outright impossible. Would any of these concepts even begin to make sense to someone without the proper context?

Now imagine you have to somehow compress all of this into a succinct 115 images, 90 minutes of music, and about 23 minutes of additional audio. This was the enormous task that NASA asked of the prominent American astronomer, Carl Sagan, back in the summer of 1977.

Twin spacecrafts, Voyager 1 & 2, were to be launched in August of that year with the primary mission to observe Jupiter, Saturn, and their many moons. Voyager 1 would be the first to eventually leave our solar system and to enter interstellar space, followed by Voyager 2. NASA wanted to have a message hitchhike along with the spacecrafts to describe who we are and where we are from in case any intelligent extraterrestrials ever came across them. Carl Sagan and fellow astronomer Frank Drake had already created a plaque for the Pioneer spacecrafts that contained a simple diagram with a mathematical based message. When NASA reached out to them, they excitedly assembled a team of friends and associates, and took up this challenge with only 6 weeks until the final product needed to be affixed to the spacecrafts. The committee included Sagan’s wife, artist Linda Sagan, author Ann Druyan, artist Jon Lomberg, and Tim Ferris, science writer and editor for Rolling Stone magazine.

The Pioneer plaque created by Carl Sagan and Frank Drake not only describes what humans look like, it also gives directions to extra terrestrial life on how to find our Solar System .  NASA on The Commons/Flickr  (public domain)

The Pioneer plaque created by Carl Sagan and Frank Drake not only describes what humans look like, it also gives directions to extra terrestrial life on how to find our Solar SystemNASA on The Commons/Flickr (public domain)


The first problem to be solved was how much information could be sent, and how? Frank Drake, who is also one of the founders of SETI (the Search for Extra-Terrestrial Intelligence), suggested a version of a phonograph record, made out of copper instead of vinyl. The information could be physically etched in the disk and easily reconstructed into both sounds and images, which would increase the variety of what could be sent. Instructions for playing the record would be on an aluminium cover in a visual scientific language that could be decoded by the finder, with a ceramic cartridge and stylus tucked away nearby. This format would be long lasting, with a life expectancy of around a billion years. Each side of the record would have 90 minutes of play per side, which allowed for quite a lot of information, but the challenge became narrowing down all the information that they felt was relevant into that space.

What made the cut?

Sagan hypothesised that the principles of physical science and maths are uniform across the universe, so most intelligent civilisations will have a similar understanding of these principals. “We can imagine a planet with uranium hexafluoride in the atmosphere or a life form that lives mostly off of interstellar dust, even if these are extremely unlikely contingencies. But we cannot imagine a civilisation for which one and one does not equal 2,” wrote Sagan in Murmurs of Earth, a 1979 book on the making of the record. Our understanding of technology and physical sciences will be displayed in the structure of the spacecraft itself, however juvenile it will appear even to us, millions of years in the future. The plaques on the Pioneer spacecrafts had portrayed information mainly about how we look, think and the location of our star. But Sagan also wanted to contain information about how we feel, which he thought would be most accurately expressed through music.


The sounds contained on the Voyager spacecrafts.


There was still the question of how one could possibly narrow the entire history of music into 90 minutes of humanity’s greatest hits. There were two criteria: there had to be a contribution from a large range of cultures, and each selection was required to touch both the heart and the mind. Every song, despite its origin or academic merit should inspire great emotion in the listener. With the help of professors in music history, passionate suggestions from every member of the team and much deliberation, an eclectic and emotive mix of music from Eastern and Western cultures was selected.

Sagan was set on including songs by Bach because of the mathematical structure of his harmonies. He hypothesised that intelligent extraterrestrial life would have a similar understanding of mathematics to ours, and hopefully perceive the meaning in this music. The inclusion of Chuck Berry’s Johnny B. Goode was controversial, and critics argued that the song was adolescent. But it’s said that Sagan decided: “There are a lot of adolescents on this planet”.

The committee worried that the listener would not be able to distinguish between musical and non-musical sounds, thus the creation of Ann Druyan’s 12 minute audio essay entitled The Sounds of Earth. It has an evolutionary direction, beginning with the music of the spheres, a musical readout of astronomical ratios by Johannes Kepler, an astronomer from the early 1600s. Each frequency represents a different planet in their motion, with the highest pitch being that of Mercury, and the lowest that of Jupiter. Following this, the recording moves through natural geological sounds such as volcanoes and rain, and then into biological sounds progressing from crickets to the sound of humans laughing and talking. Next are the technological sounds, and between the tractors and airplanes there is a message in morse code which translates to Ad astra per aspera: “To the stars through difficulties.” The recording closes with one minute of a compressed readout of Druyan’s brain waves while she was hooked up to an EEG monitor for an hour, meditating on ideas and feelings that she hoped would someday be decoded by the recipient.

In addition to the non-musical sound section, 55 salutations were recorded by fluent speakers of the vast majority of the world’s inhabitants. There were no instructions given to the speakers other than that the intention was to extend a greeting of some kind to possible extraterrestrials, and that it had to be short. Also included in this sequence was a whale greeting recorded off the coast of Bermuda, with which Ann Druyan noted: “a feeling of irony that our imagined extraterrestrials of a billion years hence might grasp a message from fellow earthlings that had been incomprehensible to us”.

For the photographic selections on the record, Jon Lomberg scoured public and university libraries for material to use. In Murmurs of Earth, he recounted: “I found myself increasingly playing the role of extraterrestrial...I would look at pictures and try to imagine that I’d never seen the subject before. How could the photograph be misinterpreted? What was ambiguous?”

There were two main aspects to the selection of the photographs: they needed to be rich in information, but also simple to understand. Only 20 colour photographs were included, as they took up three times more space on the record than those in black and white. Certain elements of the images were repeated throughout the sequence with the intention of highlighting importance or meaning. Some of the images were followed by a silhouette to reinforce what the recipient was supposed to be understanding from the photograph. One of these was supposed to be a photo of a man and a pregnant woman walking naked hand in hand, with the next slide a silhouette showing the position of the fetus. But NASA vetoed the image of the naked couple last minute, so as not to create any controversy with the public.

A selection of the 20 colour images selected to travel on Voyager's golden record depict humans in all different types of activities.  National Astronomy and Ionosphere Center/Wikimedia Commons (public domain)

A selection of the 20 colour images selected to travel on Voyager's golden record depict humans in all different types of activities. National Astronomy and Ionosphere Center/Wikimedia Commons (public domain)

What was left on the cutting room floor?

Two significant absences on the record are the representation of religion and art. The committee decided against including the major religions of Earth because they felt that there was not enough room to represent each equally. It would have been difficult to explain what religion was, and why there were so many of them in such a short space. The hope was that some of the songs would express the spirituality of humans.

Art was omitted because when trying to decipher the contents of the message from an extraterrestrial point of view, it might not be clear that art is an interpretation of reality rather than reality itself. Interpreting the photos and diagrams would be complicated enough for someone unfamiliar with the reality of Earth without adding another layer of complexity. Imagine seeing artwork by Picasso or Salvador Dali from an alien perspective; it’s easy to see how someone who had never seen Earth for themselves could confuse these paintings with a scene that existed outside of the canvas. If the goal of the message is to communicate our planet in a clear and concise manner, it seemed best to leave the art and religious education until the day our curious neighbours come to visit.

There is also a marked lack of any representation of war, violence, disease, crime, and poverty anywhere on the record. The committee ultimately decided against it because they didn’t want to present any of these negative aspects of humanity for our recipients to misinterpret as a threatening message of hostility, when the true intention was peace and goodwill. A photo of a nuclear explosion or the sound of gunshot might appear to our alien recipients as us flexing our intergalactic muscles. If we end up destroying ourselves and our planet, this message will potentially be one of the only remnants of Earth in the universe. Even if it is not a complete picture of what life is like, the Voyager team didn’t want our legacy to negatively highlight our flaws, and instead decided to make a lasting, positive, ideological statement.

As a resident of this planet, it comforts me to think that despite all of the awful things that have happened in the past and continue to happen every day, it’s the things that I love about humanity that will ultimately persevere. Our capacity to create and imagine, the uniqueness and grandeur of nature, and our awe and wonder at the world around us will all continue on regardless of how we meet our end.

Looking to the future

As the Voyager spacecrafts hurtle into space, astronomers on Earth are gearing up for what’s next in the field of active SETI, also known as METI (Messaging Extra-Terrestrial Intelligence). Traditional SETI is passive, waiting for extraterrestrials to contact us and searching for their signals. Active SETI is well, active. Repeatedly sending intentional messages via targeted lasers or Interstellar Radio Messages (IRMs) to close, Earth-like planets with the hopes of getting a message back. These forms of information can travel much faster than a physical spacecraft like Voyager, ensuring a speedy delivery.

The first message METI is planning to send will be in 2018, directed towards the closest star to our sun, Proxima Centauri. So far, there are no international laws regarding what messages you can send into space, which means that METI is pretty much unregulated. That doesn’t mean that everyone in the science community is behind the idea of alerting our neighbours to our existence without having a thorough international discussion of all the relevant scientific, global, and political consequences.

Since the first radio transmissions in the 1890s, there has been a sphere of man made radio signals extending out at the speed of light into space in all directions. We’re past the point of no return then, if there is extraterrestrial life out there they may already be about to hear some of our old radio broadcasts. We don’t want extraterrestrials getting the wrong idea about who we are, so sending out a message and letting them know we’re ready to talk doesn’t seem like such a bad option.

After all the effort that goes into constructing these cryptic letters, it is unknown whether anyone will actually receive them. The Voyager spacecrafts contain a heartfelt message in a bottle, tossed into the cosmic ocean with no promise of return. As B.M. Oliver says in Murmurs of Earth, “There is only an infinitesimal chance that the plaque will ever be seen by a single extraterrestrial, but it will certainly be seen by billions of terrestrials. Its real function, therefore, is to appeal to and expand the human spirit, and to make contact with extraterrestrial intelligence a welcome expectation of mankind.”

It puts a lot of things in perspective when you look at your life from a cosmic point of view. What brand your shirt is, how many followers you have on Instagram, and how much money you’ve accumulated does not maintain its significance in the grand scale of the universe. A larger frame of reference helps us prioritise what is really important, and how we want to live our day to day lives.

Edited by Tessa Evans and Bryonie Scott