Humanity's Most Famous Mixtape Is Now 11 Billion Miles From Earth
With every second that ticks past, the spacecraft Voyager 1 ventures farther away from Earth. You can actually watch this happen, in a way, on NASA's website, which tracks the probe's distance from our planet with a meter that's constantly counting up. Voyager is moving away from our sun at a clip of nearly 1 million miles a day.
Since its launch 37 years ago this month, the spacecraft has become humankind's farthest flung object. Today it is more than 11 billion miles from home, a distance equivalent to nearly half a million trips around the planet Earth.
Yet all these years later, from a galactic vantage point that seems impossibly far away, Voyager is still sending data back to scientists on Earth. And even when its last instruments power down in 2025, the spacecraft will continue to carry one of humanity's greatest hopes: the prospect of communicating with intelligent life elsewhere in the universe. That was the idea, anyway, behind the Golden Record, copies of which were placed aboard both Voyager 1 and its predecessor, Voyager 2, which was launched first but on a slower trajectory.
The gold-plated copper disc features a rather romantic sampling of Earthly sounds—the music of Igor Stravinksy and Chuck Berry, human greetings in dozens of languages, the staccato of an infant's cry, an urgent train whistle, choruses of crickets, and a whale's ethereal song. The record's case is etched with images explaining how to play it. Here's the complete playlist:
The chance that intelligent life might ever encounter this interstellar mixtape—let alone listen to it—has always been infinitesimal. Still, argued astrophysicist Carl Sagan, who helped select the tracks, "the launching of this bottle into the cosmic ocean says something very hopeful about life on this planet." There is indeed something lovely about sharing humanity with the universe in this way, as Megan Garber wrote last year:
The Golden Records ... carry the transcendent aspects of human existence: the art, the beauty, the ache, the joy. They offer what we have, and what we are, up to the cosmos.
But what if the improbable were to happen? Here on Earth, 10-year-old CDs are puttering out. What about a pair of 40-year-old records careening through outer space? Even if extraterrestrials found and figured out how to work the Golden Record, would it play anymore?
Actually, yes, experts say.
"The gold records that were launched into space were specially constructed discs for the purposes of space travel," said Peter Alyea, a digital conservation specialist at the Library of Congress who specializes in audio recordings. "I believe they were designed to last for a very, very long time and so should still be playable. This kind of disc is not something you could buy commercially at a record store."
And besides, Voyager's Golden Record has thus far been kept safe from the elements—high temperatures, oxygen, water—known to deteriorate Earthly records. (Voyager is now operating at about negative 110 degrees Fahrenheit.)
“If I had to guess, I'd say it's as fresh and new as the day it was placed aboard the spacecraft," said David Doody, an engineer on the Voyager mission at NASA’s Jet Propulsion Laboratory, in an email. "It's been stored in a vacuum more perfect than any attainable on Earth, and protected from dust and cosmic rays by an aluminum metal case."
That protective aluminum case has had quite the adventure—it got a dose of radiation near Jupiter and was blasted with space dust in Saturn's ring plane—but Doody says it has been "basically always shielded" at least enough to protect the record's functionality. "In all, it might have lost a little luster at worst, in my humble opinion," he said. "I'd also venture to guess that it would be in playable condition for many hundreds of millennia.”
Which raises a theoretical question about what version of Earth the rest of the universe might first encounter, and what songs or sounds we might include today that didn't exist in 1977. The Golden Record, after all, is more of a time capsule than a broadcast. (It doesn't even include any hip-hop, which was still in its cultural nascence the year the Voyagers were launched.) Of course many of the record's sounds have retained the timeless quality they must have had four decades ago—like this greeting from Kurt Waldheim, then the secretary general of the United Nations:
We step out of our solar system into the universe seeking only peace and friendship—to teach if we are called upon, to be taught if we are fortunate. We know full well that our planet and all its inhabitants are but a small part of this immense universe that surrounds us, and it is with humility and hope that we take this step.
NASA has since moved on to new projects to share music with other galaxies, and humanity has graduated beyond the record as the go-to audio format. In 2008, for instance, scientists beamed a song directly into deep space, aiming for the North Star 431 light years away from Earth. That tune, a Beatles classic from the decade before Voyager launched, was "Across the Universe."
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