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Designing the Interstellar Doorbell (Or How to Talk to ET)

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Designing the Interstellar Doorbell (Or How to Talk to ET)

Designing the Interstellar Doorbell (Or How to Talk to ET)

Hands and moon
(Getty Images)

Last month at the SETI Institute in Mountain View, an international group of scientists, linguists, philosophers and others convened in a workshop to discuss what might be the most challenging conversation in the history of humankind.

If we could send a message to an intelligent extra-terrestrial on some distant planet, they asked, what would we say?This is not a new question. NASA’s asked it. The Russians and the Japanese have asked it. Doritos asked it. They seem to have asked it a lot in the 1970s.

Kepler’s Contribution

But there’s a very good reason to be asking it again now, in 2014. Thanks to the Kepler Telescope, we won’t just be sending messages out into the aether anymore. We have addresses.

Since its launch in 2009, Kepler has identified hundreds of planets outside our solar system. Some are rocky and Earth-like, orbiting distant stars. Maybe they have -– or, like Mars billions of years ago, they might once have had — mountains, clouds, lakes and oceans, even life.


We can direct powerful radio transmissions at these planets and hope some form of life knows how to receive them.

“If there’s life out there,” says Douglas Vakoch, SETI’s Director of Interstellar Message Composition, “our chances of finding it have increased astronomically.”

So What Should We Say?

Humanity’s attempts to answer this question (maybe not all attempts) take two basic forms. There are physical objects (e.g., the Pioneer Plaques) that we’ve attached to unmanned spaceships on a one-way mission — like messages in a bottle that some space-faring alien might stumble upon. Then there are powerful radio signals such as the Arecibo message, which was broadcast from a radio telescope in Puerto Rico in 1974.

But in terms of  messages that try to sum up the subjective experience of being alive on Earth, the gold standard is a pair of 12-inch copper discs that were attached to the Voyager 1 and 2 spacecrafts in 1977. The Voyagers were launched on missions to explore Saturn and Jupiter (plus Uranus and Neptune for Voyager 2) then drift into the universe, indefinitely.

NASA broadcast the Beatle’s hit “Across the Universe” toward the star Polaris on the 40th anniversary of the song’s recording in 2008. (NASA/JPL)
NASA broadcast the Beatle’s hit “Across the Universe” toward the star Polaris on the 40th anniversary of the song’s recording in 2008. (NASA/JPL)

The Golden Records were an afterthought. A team led by Carl Sagan saw the opportunity for an interstellar postcard and filled the discs with images, with greetings in different languages and with music from Beethoven to Blind Willie Johnson.

There’s also the sound of a heartbeat and a volcano. A mother comforting her child.

“Have you eaten yet?” asks a speaker of Min Chinese. “Please contact us,” pleads a man speaking Gujarati.

One musical passage in particular captures a range of human experience, Vakoch says, moving from an orderly Bach piano piece into mournful bagpipes and then into a thunderous passage of Stravinsky’s Rites of Spring.

“Will an extra-terrestrial understand what it means?” he asks. “Certainly not in the way we do.”

That may be a moot point. Vakoch says at its current pace, the Voyager spacecraft — and the records inside it –- won’t come close to another star for another 75,000 years.

Radio messages could take “only” hundreds of years to reach their destination. But that’d still make for an awkward conversation. If ET got our message and responded, no one on Earth today would be alive to hear it. Would our great-great-great-grandchildren even remember what we’d said?

That quandary assumes an even greater feat: that the extra-terrestrials are able to decode our message in the first place.

How do you communicate with a life form you know absolutely nothing about? Will these extra-terrestrials have language? If we sent an image, could they see it? Even a simple series of numbers — say a Fibonacci sequence — may be as anthropocentric as a line of Shakespeare.

Send Everything? Or Just One Thing?

Faced with all this uncertainty, participants at the SETI workshop last month fell into two rough camps: Send ET everything — as in the entire Internet — or send them one thing -– a kind of interstellar doorbell.

I’ll explain the doorbell in a minute.

The send-them-everything camp, Vakoch says, argues that a smarter, more technologically advanced alien civilization might search the Internet and find patterns. Eventually, they might crack the code of human language, even without an interstellar Rosetta Stone.

These civilizations are likely much older than ours, says SETI’s Seth Shostak, since any message we receive would have been sent hundreds of years ago. And they’re likely more technologically advanced.

“These aren’t soft squishy guys who are interested in arts or music, at least our art and music,” he says. “They’re machines of some sort. Advanced societies will say that more bits are better. More information is better.”

This struck the other camp at the conference as a really bad idea, maybe even impolite, the equivalent of meeting someone at a party and just screaming at them for an hour.

What if, they said, we sent them something drastically smaller: a simple signal, a kind of doorbell.

“The idea of a doorbell indicates a query, an openness,” Vakoch says. “It’s not a demand to be let in. It’s an indication of the desire to make contact.”

An Olfactory Message

Los Angeles artist Carrie Paterson came to the conference to present a radical idea, even among a crowd of unconventional thinkers: that our message might consist of a “symphony of smells.”

“I think the whole point is to send a kind of poem that provokes some curiosity about us,” she says, “some desire to respond.”

The content for the Teen-Age Message was decided by Russian adolescents.  It included the “1st Theremin Concert for Aliens” and was sent toward six nearby stars in 2001. (Rumlin/Creative Commons)
The content for the Teen-Age Message was decided by Russian adolescents. It included the “1st Theremin Concert for Aliens” and was sent toward six nearby stars in 2001. (Rumlin/Creative Commons)

Smells, Paterson points out, are chemical cues, the same language used by thousands of species on Earth.

The hope, she says, is that we might “create something a tree would understand.”

How, exactly, do you transmit a smell 25 million light years? No one really knows.

Paterson’s point is that whatever we send should represent all of our planet. Not just humans. Not just scientists. Not just Americans.

Vakoch agrees. He’d love to see the United Nations involved, to make this a global question.

“If the Secretary-General calls us up,” Vakoch says, “and says, ‘We’d like to have a special session on this,’ I’d be delighted.”

In the meantime, Vakoch has built a website to collect suggestions from all over the world: Earth Speaks.


Whenever some kind of consensus emerges, maybe it’s time to hit send, and hope someone out there is listening.

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