Hi.

It’s one of the simplest greetings we have—one syllable, two letters, maybe joined by a friendly wave. But how would you say “Hi” to someone on the other side of the city? On the other side of the world?

How about to someone who’s thousands of light-years away, whose language you don’t know, whose anatomy you don’t know (do they have eyes?), and whose technology is a mystery? How would you say “Hi” then? How would you even indicate that we’re here, on Earth, calling out into space to see if anyone will call back?

That’s what Douglas Vakoch and the team of scientists at Messaging Extra Terrestrial Intelligence, or METI, are trying to figure out. “It’s daunting,” Vakoch said with a laugh during a recent interview.

Establishing common ground

METI, an outcropping of the SETI—Searching for Extra Terrestrial Intelligence—project, is planning to send a series of messages into the stars starting in 2018. But how do you send a message to a lifeform you know nothing about? And what should you say?

Northeastern lecturer and linguistics expert Adam Cooper has some ideas on the former.

If aliens do have language, as linguists conceive of it, any hope of understanding it would rely on its being systematic and rule-governed. The rules may not be immediately obvious to us, but they’d have to be there.

Adam Cooper
Senior Lecturer, Linguistics Program

“If you think about it, having a common foundation of understanding is at the heart of successful communication via language,” Cooper said. As anyone who has attempted to speak to someone who speaks a different language can attest, Cooper added, “Speakers who don’t share knowledge of the same language won’t be able to understand each other.”

The key, then, is to establish some common ground. Here on Earth, at least, one can rely on certain fundamental building blocks of language and go from there.

“Many linguists support what are termed ‘design features’ of language,” Cooper said, which include discreteness and duality of patterning. This means that language consists of isolatable, repeatable units.

Cooper explained: “To take an example, the sounds ‘r’ and ‘e’ can be combined to form the morpheme re- (a prefix), which can combine with verbs to form words like redo, retype. These words can figure in sentences, as in I have to retype the paper, which in turn can figure in yet larger sentences, as in Max thinks I have to retype the paper, so on and so forth. At any linguistic level, discrete units can be identified, and these can be manipulated in any number of language-specific ways to create linguistic utterances.”

Furthermore, in order for humans to have any hope of deciphering a message that came back to us, the alien language would need to operate under these same basic principles.

“If aliens do have language, as linguists conceive of it, any hope of understanding it would rely on its being systematic and rule-governed,” Cooper said. “The rules may not be immediately obvious to us, but they’d have to be there.”

‘Two plus two equals four’

But for now, Vakoch and METI are focused on getting the message out there.

He and his team have determined that the common ground Cooper mentioned must be math. As their thinking goes, any civilization that has built technology sophisticated enough to receive a message from trillions of miles away must also understand at least the basic concepts of mathematics.

“It’s hard to imagine you’d be able to construct such a piece of technology without knowing that two plus two equals four,” Vakoch said.

So the team will send messages that communicate their essential ideas through the signal itself. That means sending radio pulses of a set duration and frequency, then pointing back at those building blocks to explain slightly more complex information about us.

For example, a pulse that lasts for two seconds would be followed by the “word” for two. As The New York Times explains, “The words for basic math properties can be conveyed by combining pulses of different lengths. You might demonstrate the property of addition by sending the word for ‘three’ and ‘six’ and then sending a pulse that lasts for nine seconds.”

This gives scientists a way to communicate concepts without pointing back at anything—an essential part of language-learning here on Earth.

“Considering the possibility of communicating with aliens, I can’t help but think of the experience that, say, European explorers must have gone through in encountering peoples across the globe who spoke languages completely unrelated to their own,” Cooper said.

“In the very initial points of contact, how did communication play out? At least in this scenario, even in the absence of a shared language, the interlocutors would have shared the common experience of being in the same place—so one imagines that a lot of gesturing and pointing may have been involved at the outset,” he said. “With aliens, attempting communication over long distances, we wouldn’t have the benefit of that shared context, which makes the enterprise that much more challenging to conceptualize.”

Indeed, the challenge was a knotty one. Referencing a scene in the science fiction film Arrival, in which actress Amy Adams’ character communicates with an alien on Earth, Vakoch said, “I was so envious of her—she was right across the room from the alien, so she could try a lot of different things to communicate. We don’t have that luxury, so we need to send as fool-proof a message as we can.”

Hello from the other side

With that solved, the question becomes: What do we say?

Vakoch said the message will start with simple counting, then move on to basic arithmetic: addition, subtraction, multiplication, and division, and then a description of trigonometry. From there, the message will move on to introduce units of time.

“The nice thing about trigonometry is that you can use some very simple math to give you a fraction,” Vakoch said. “In a wave, you use that fraction to describe how the wave is oscillating.”

It’s hard to imagine you’d be able to construct such a piece of technology without knowing that two plus two equals four.

Douglas Vakoch
President, METI

Cooper’s theory? Just send something peaceful. Though even that may prove tricky.

“I would think one would want to send as peaceable a message as possible,” he said. “Of course, intending to be pleasant in our communication doesn’t guarantee that we will actually be received as such—just think of all the misunderstandings we can encounter in our day-to-day existence, speaking to other humans. Without a broader knowledge of the culture in which the aliens exist, we’d be hard-pressed to fashion a message that can be assured of success.”

Return to sender

His point raises a concern many, including theoretical physicist Stephen Hawking, share: Do we even want to let others know we’re here? Might this not be inviting an alien invasion?

To that, Vakoch says that anyone who would be able to receive this message already knows we’re here.

If there are civilizations that already have the ability to reach Earth, he said, “then they already have the technology to know we’re here…and may already be on their way.”

That exact issue of distance calls up another concern: Many of the stars toward which the message will hurtle are thousands, if not hundreds of thousands of light-years away. By the time the message gets there, no one who sent it will be alive to know.

Vakoch acknowledged this.

“Making contact with another civilization is something that would be important for humanity,” he said. “It would present a new way of understanding ourselves; we’d be able to hold a mirror up to ourselves by comparing ourselves to another civilization. So, METI as a project is a statement of our commitment to survive—our intention is to be around to get a reply back.”

As such, Vakoch said he and his team are working diligently to establish the best way to preserve a record of the messages that are sent—a record that would be handed down from generation to generation until one is received in return.

“I would hate to get a reply back and then not remember what they replied to,” Vakoch said.