Excerpted: The Language of the Stars

Imagine you’ve been tasked with mailing a letter to a friend whose only language is more foreign to you than Shakespeare is to a hamster. Without the thankless assistance of Duolingo or Google Translate, how would you direct-message this fellow to tell them about your culture, the planet you inhabit, and your species? They’ve never known a smidge of your society, your memes, your poetry, customs or traditions—and they’re not too enthusiastic about a meetup, given that their home is over a dozen trillion kilometers away. What lingo could you possibly both understand?

NASA was preoccupied by this conundrum in 1972 as it neared the historic launch of the Pioneer 10 and Pioneer 11 spacecraft.

Those two space missions aimed to slingshot past the outer planets of Jupiter and Saturn, sending us back a mountain of new data. But scientists knew these probes weren’t coming back. Their orbits would slingshot them up to 65,000 kilometres per hour, enough to slip the bounds of the Sun’s gravitational riptide and sail into the galactic void forever.

Knowing this, the astronomer Carl Sagan suggested that a little message get tagged onto the probes—a cosmic greeting from the human race. In one of the narrowest deadlines in rocket science history, Sagan had three weeks to compose a message with artist Linda Salzman and astronomer Frank Drake. Scrawled onto a gold plaque, that message became like humanity’s first profile picture in the cosmic group chat. It was our first intentional alien-coded message.

But how could humans—a species who often can’t even make sense of smalltalk in their own language—be capable of communicating to an alien creature who likely knows less about human behavior than a muppet? If we ever made contact with alien life, would humans fall flat on our faces in a fruitless attempt to speak in some daft language of the stars, or might we find a lot more in common than we think?

For simplicity’s sake, Carl Sagan swept aside all culture and politics. If you’ve seen the media lately, or basically ever, you’ll know that we’re capable of babbling and rambling on about that for decades. Sagan wanted to convey just one simple message on the plaque: where we live, and what we are.

It’s hard to mail your cosmic address into space when none of your recipients know what a postal code is, but we found a method using pulsars, the fast-spinning husks of long-exploded dead stars.

These beacons were discovered in 1967 when astronomer Jocelyn Bell Burnell noticed a telltale blinking pattern in the skies. Like cosmic lighthouses, pulsars shine two twirling beams of light into the universe. We mapped those as our reference points, which is like mailing your home address in relation to the nearest graveyards. I do it all the time.