A radio message will be sent to an alien solar system this year. What should it say?

METI International, a California organization set up in 2016 to pursue what’s sometimes called “active SETI,” has announced it will send a radio message from the world’s first commercial deep space network, located in Goonhilly, England, to the TRAPPIST-1 exoplanet system later this year.

Located 39 light-years from Earth, the TRAPPIST-1 system was chosen because its central star may host several habitable planets. So there’s a chance — albeit a slim one — that this transmission could be humanity’s first contact with an alien civilization. While that would be an amazing feat to pull off, a nagging question remains: Is it wise to send out such a message?

Many scientists, including the late Stephen Hawking, answered with an emphatic “no.” They suggest that we stay in listen-only mode, lest we invite trouble. (Readers of Liu Cixin’s science fiction trilogy The Three-Body Problem will understand.) While the aliens alerted to our presence wouldn’t necessarily have to be as vicious as those in the movie Independence Day, potential conflicts could easily arise from misunderstandings. The proponents of active messaging counter this argument by saying that we have already been sending out radio signals for nearly 100 years. If aliens have the technology to invade and intend to, they already know where to find us.

Personally, I find both viewpoints reasonable. However, since Earth is currently our only lifeboat in the interstellar ocean, I think it is prudent to err on the side of caution. It is disconcerting that there are no rules in place regarding who can transmit messages that could lead to our first contact with an alien civilization. One would think the United Nations might have something to say about it, but as things stand, anyone with a large enough transmitter can send whatever he or she wants into space.

Alien text messages

The plan by METI International raises another big question: If we agree in principle that it’s okay to send a transmission, what should the message be?

For a project it calls Stihia Beyond, the group and its partners are designing a message to “explain humanity’s environmental crisis in terms of universal chemical principles,” which will be beamed into space along with selected pieces of music on October 4 of this year. I am eager to see the detailed message and how they intend to convey it to an alien civilization. I wonder what the residents of TRAPPIST-1e, if there are any, would make of it. Could it be that the message is really targeted toward Earth’s population? If we aren’t able to fix the climate crisis ourselves, we may not be ready for contact with an alien civilization.

I am also wondering how the music would be received. Alien reactions may range from annoyance to pleasure, or they may try desperately to decode a deeper meaning from it.

Of course, this is not the first group to design an interstellar message, the most famous of which was the “Golden Record” attached to the Voyager spacecraft. Nearly 50 years ago, in 1974, a message beamed from the Arecibo radio telescope in Puerto Rico was the very first attempt to send out a transmission meant to be understood by aliens. So far there’s been no reply.

Recently, a science team led by Jonathan Jiang from the Jet Propulsion Laboratory proposed a new message, which they call “Beacon in the Galaxy,” that essentially updates the Arecibo message by maximizing its information content about humanity, while using as few data bits as possible. Like the Arecibo message, Jiang’s message is binary coded and includes pixelated images. It begins with basic mathematical and physical concepts to establish (they hope) a universal lexicon, followed by a description of the biochemical composition of life on Earth. The aliens are given a way to determine our location: a time-stamped position of our Solar System in the Milky Way relative to certain easy-to-identify globular clusters. The message also includes digitized depictions of the Solar System and Earth’s surface, as well as digitized images of a female and a male human. It ends with an invitation to any receiving intelligent species to respond.

Will they get the message?

While the METI team will send their message to a star that is relatively close to Earth, Jiang and his colleagues propose targeting a star cluster thousands of light years away, near the center of our galaxy. This seems nonsensical to me. The message would take many thousands of years to reach an extraterrestrial civilization, and by the time it arrived, the signal would surely be degraded to radio noise. Understanding an alien culture’s message is hard enough. This degradation might make it impossible. Even METI’s transmission to the TRAPPIST-1 system might have a lot of static by the time it arrives 39 years later.

That might be a comfort to those worried about the perils of interstellar messaging, however. Time and the incredible distances between the stars are on your side.