How to Design an Interstellar Message for Extraterrestrials

If you could say something to an alien, what would you say and how would you say it?

In 1950, the Italian physicist Enrico Fermi asked a question that's become known as the Fermi Paradox: where are they? If in fact there's intelligent life in the universe, why haven't they contacted us? Well, one possibility is the zoo hypothesis. Maybe extraterrestrials are out there, perhaps even at the nearest stars, but they're simply observing us, sort of like how we watch animals at a zoo. Perhaps the protocol for making first contact requires humans to take the initiative. That's what METI is testing. 

Douglas Vakoch is the president of METI, a group dedicated to messaging extraterrestrials. For years he worked at the SETI Institute as the director of interstellar message composition, and his work is to prepare for the day we detect a signal and we need to decide should we reply? What should we say? A number of SETI organizations have focused their energies on simply listening. And after a number of years, Doug and a team of astronomers, linguists, and engineers have decided it's time to move forward. 

But a move from listening for signals to beaming intentional ones has been the subject of intense controversy. A petition signed by scientists warned that "we know nothing of [an extraterrestrials] intentions and capabilities, and it is impossible to predict whether [they] will be benign or hostile." For METI’s critics, the unknown is a good enough reason to stay quiet. And they insist on global consensus before any message is sent out. But that hasn’t stopped METI from forging ahead anyway.

"The key to remember is the signals that we sent off in the 50s and 60s and 70s...are all travelling outward at the speed of light. So for anyone who says we should hide from the extraterrestrials, I've got some bad news for you, it's too late." 

This isn’t the first time we’ve tried to broadcast our existence to the cosmos, and one of the most famous examples is the Arecibo message. Back in 1974, Carl Sagan and astronomer Frank Drake sent 1,679 pulses of light into space from the Arecibo telescope in Puerto Rico. If an alien translated it, they would see the numbers 1-10, the basic chemical elements for life, a double helix, and a human figure.

"The Arecibo message is an ambitious message….it's an encyclopedia written in the language of science. And while that's laudable to try and tell the extraterrestrials a lot, I think it's overly ambitious. Plus, the Arecibo message targeted a globular cluster of stars called M13, 25,000 light years from Earth. That means any reply we get back will take 50,000 years. Surely we can do better than that." 

"In our next round of transmissions, we're getting three types of messages ready. One will describe basic chemical principles, we'll send the periodic table of elements. The second will describe the human body. The third message will go on to describe something about how we engage with one another, altruism.  As we design a message for extraterrestrials, we need to ask what we and the extraterrestrials have in common. Well, we have in common the universe itself. So when we look around the universe and try to describe it, we start with what it's made up of. Hydrogen and helium and carbon and oxygen and phosphorus and all these 200+ chemical elements. Well that's something that scientists on another world will know about too." 

METI is currently moving forward with its plan to send interstellar transmissions next year. Their efforts to make contact raise questions about whether we should send messages at all, who should speak for Earth, and ultimately, what this says about us.