Embedded in the Sounds of Earth section of the Voyager Golden Record is something that does not appear on any track listing: an hour-long recording of the heartbeat and brainwaves of Ann Druyan, compressed into the span of a minute to fit onto the record. It sits inside a broader sound montage, not catalogued alongside the 27 musical selections. Most people who know the record know it for Chuck Berry and Bach. This detail tends to go unremarked.
The recording was made on 3 June 1977, at Bellevue Hospital in New York City. Druyan had asked Carl Sagan whether, if she recorded her brainwaves with an electroencephalogram and electrocardiogram, aliens could eventually read her mind. Sagan and the others liked the idea, and volunteered Druyan to provide the brainwaves. Druyan prepared a script to guide her thoughts, “a mental itinerary of the ideas and individuals of history” whose memory she hoped to preserve.
Two days before the session
On 1 June 1977, Carl and Ann shared a “wonderfully important phone call” and decided to get married. The EEG session was already booked. As Druyan later wrote in the epilogue to Sagan’s book Billions and Billions: “Earlier I had asked Carl if those putative extraterrestrials of a billion years from now could conceivably interpret the brain waves of a meditator. Who knows? A billion years is a long, long time, was his reply. On the chance that it might be possible why don’t we give it a try? Two days after our life-changing phone call, I entered a laboratory at Bellevue Hospital in New York City and was hooked up to a computer that turned all the data from my brain and heart into sound.”
The Golden Record carries that hour-long recording of Druyan’s brainwaves, compressed into a minute of audio. During the recording, Druyan thought of many topics, including Earth’s history, civilisations and the problems they face, and what it was like to fall in love. In her own account, the session had a prepared structure. She began by thinking about the history of Earth and the life it sustains, then tried to convey something of the history of ideas and human social organisation, thought about the predicament civilisation finds itself in, and only toward the end of the hour permitted herself a personal statement of what it was like to fall in love. The recording sits closer to a meditation on the whole of human experience, with a love letter folded in at the end, than to a love letter on its own.
In a 2010 interview with Radiolab, Druyan put it plainly. “This was two days after Carl and I declared our love for each other,” she said. “And so… part of what I was thinking in this meditation was about the wonder of love and of being in love.” The word “part” does a lot of work there, and Druyan used it deliberately.
What the signal actually sounds like
The session captured Druyan’s brainwaves via EEG, her heartbeat through an electrocardiogram, and other vital signs while she contemplated topics including the history of Earth, the evolution of life and civilisations, and her recent feelings for Sagan. Those signals were analog-encoded and electronically compressed into a one-minute audio track, producing a sound resembling rapid bursts or firecrackers when played. The compression is extreme enough that the resulting audio bears no obvious resemblance to thought.
That gap between signal and meaning is the point Druyan herself was reaching for when she proposed the idea. “I had this idea,” she recalled, “that we should put someone’s EEG on the record. We know that EEG patterns register some changes in thought. Would it be possible, I wondered, for a highly advanced technology of several million years from now to actually decipher human thoughts?” No one answered that question in 1977. As far as current neuroscience can determine, the brainwave recording is unreadable without the context of the brain that produced it, the moment it was produced, and a decoding framework that does not yet exist.
Artist Dario Robleto, who has spent years working with the recording as source material, framed the open question in terms of empathy rather than technology. He has returned often to whether it would be possible for someone, perhaps an alien lifeform happening upon one of the Voyager probes, to work out what Druyan was thinking that day in 1977 from the recording of her EEG. His conclusion was that the answer might depend less on the alien’s instruments than on whether they had any concept of interiority at all.
Where the record is now
Both Voyager 1 and Voyager 2 have reached interstellar space and continue travelling outward. Voyager 1 entered interstellar space on 25 August 2012, making it the first spacecraft to do so. Voyager 2 crossed the heliopause and entered the interstellar medium on 5 November 2018. Voyager 1 is currently exploring interstellar space 15.8 billion miles away, and the two Voyagers are the only human-made objects to have passed into interstellar space.
Affixed to the side of each craft is a golden audio-visual record with 90 minutes of storage and a billion-year shelf life, still bolted to the hull. The record was designed to outlast the mission, the mission team, and in all likelihood the civilisation that built it. In about 40,000 years, Voyager 1 will pass within 1.6 light-years of the star Gliese 445, the closest approach to any star system currently on the trajectory. Whether anything is there to notice remains unknown.
What is fixed is the record’s contents. Somewhere in the compressed minute of neurological data is a pattern that, on 3 June 1977, corresponded to a 27-year-old woman thinking about Earth’s deep past, the condition of human civilisation, and, toward the end of an hour, the fact that she had just agreed to marry someone. As Sagan himself noted, “The spacecraft will be encountered and the record played only if there are advanced space-faring civilizations in interstellar space, but the launching of this ‘bottle’ into the cosmic ‘ocean’ says something very hopeful about life on this planet.” The brainwave recording says something more specific, and something that may remain permanently private: the inner life of one person, encoded in a format no one yet knows how to read, moving away from Earth at roughly 38,000 miles per hour.
