How would we decode a message from ET? New project will give us a trial run

Radio telescopes in northern California against a dark sky with the Milky Way visible.
The Allen Telescope Array in Northern California is dedicated to astronomical observations and a simultaneous search for extraterrestrial intelligence (SETI). (Image credit: Seth Shostak/SETI Institute)

A new project aims to help prepare humanity for the day — should it ever come — that we make contact with intelligent aliens.

At 3 p.m. EDT (1900 GMT) on Wednesday (May 24), Europe's Trace Gas Orbiter (TGO) Mars probe will send a coded message that will be received by three big radio telescopes here on Earth.

Scientists around the world — and interested members of the public — will then attempt to decode the missive, as part of an ambitious, multiweek project called A Sign in Space.

"This experiment is an opportunity for the world to learn how the SETI [search for extraterrestrial intelligence] community, in all its diversity, will work together to receive, process, analyze and understand the meaning of a potential extraterrestrial signal," Wael Farah, project scientist for the Allen Telescope Array (ATA), a network of dishes in Northern California run by the nonprofit SETI Institute, said in a statement

"More than astronomy, communicating with E.T. will require a breadth of knowledge," Farah said. "With A Sign in Space, we hope to make the initial steps towards bringing a community together to meet this challenge."

Related: The search for alien life (reference)

The ATA is one of the three facilities that will pick up the TGO message, which will take 16 minutes to reach Earth from Mars orbit. The other two are the Robert C. Byrd Green Bank Telescope at the Green Bank Observatory in West Virginia and the Medicina Radio Astronomical Station in northern Italy, which is managed by the Italian National Institute for Astrophysics.

Teams at each of the three observatories will process the coded signal and make it available to the public. So, if you're interested, you can try your hand at deciphering it — and submit your solution and other ideas via the project's website.

Indeed, public engagement is a key part of A Sign in Space, which is led by Daniela de Paulis, the current artist in residence at both the SETI Institute and the Green Bank Observatory.

For example, the project will host a webcast on Wednesday that features interviews with team members and live look-ins at the control rooms of the three radio telescope sites. The livestream will begin at 2:15 p.m. EDT (1815 GMT), 45 minutes before TGO beams out its message.

And, over the ensuing six to eight weeks, the project team will host a series of public Zoom meetings that will discuss the societal implications of spotting a signal from an alien civilization.

"Throughout history, humanity has searched for meaning in powerful and transformative phenomena," de Paulis said in the same statement.

"Receiving a message from an extraterrestrial civilization would be a profoundly transformational experience for all humankind," she added. "A Sign in Space offers the unprecedented opportunity to tangibly rehearse and prepare for this scenario through global collaboration, fostering an open-ended search for meaning across all cultures and disciplines."

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Mike Wall
Senior Space Writer

Michael Wall is a Senior Space Writer with and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.

  • Dave
    We are on the listening end, but it is important to know first, how we would send a signal. Mathematics is the universal language. Building images using various methods would be one way to communicate.
  • dcourney
    Think I might mess around with this.

    Assuming this is some kind of digital signal, the first thing I would try is count the number digits. Then see if it is a perfect square or the product of two primes. This could give the aspect ration if the message is a 2 dimensional picture. If not a perfect square or product of two primes; try dividing the total numbers of digits by 2,3,4, ...., If the answer is a perfect square or the product of two primes; then each pixel in the picture could composed a multi digit shade.

    This idea could be extended to three dimensions. See if the totaal number of digits is a perfect cube or product of 3 primes.
  • Jasper
    Might be the message is loud and clear to us all.
  • Classical Motion
    Any frequencies below near IR, could not be used for communications, unless the range is extremely close. As far as any can concept, it would take the intensity of a star to have any "space range" at all. So for space radio, one has to modulate a star.

    For alien messages......look for blinking stars. Or "motor boating" stars. I'll bet few have heard that term.