While the Search for Extraterrestrial Intelligence (SETI) program is content to scan the skies for signals that might indicate the presence of life on other planets, the related program Messaging Extraterrestrial Intelligence (METI) aims to take a more active approach. METI and other organizations have now beamed radio transmissions, containing snippets of music, to a potentially-habitable planet about 12 light-years from Earth, in hopes of making first contact.

The target is an exoplanet called GJ273b, orbiting Luyten's Star some 12.4 light-years away. Only discovered in March this year, the world is a "Super Earth" with a mass about three times that of our home planet that orbits well within the habitable zone of its cool red dwarf parent star. Those life-friendly conditions, along with its proximity to Earth, make it a good candidate for sparking up a neighborly chat.

METI, in partnership with the Institute of Space Studies of Catalonia (IEEC) and the Spanish music festival Sónar, transmitted the first radio signals to GJ273b last month. The "Sónar Calling" transmission starts with a tutorial in binary code, designed to instruct any recipients on how to decode the message that follows, which is made up of 33 pieces of music lasting 10 seconds each that were commissioned from a range of artists from the festival's past lineups.

Using the EISCAT antenna in Norway, the first signal was beamed out on October 16, then repeated on October 17 and 18 to help any listeners correct errors that occur during the 70-trillion-mile journey. The message – which has apparently already hurtled out of the Solar System into interstellar space – is due to arrive at GJ273b in November 2030, and the team says that if there's anyone there, the call could be returned in about 25 years' time. A second transmission is planned to be sent in April 2018.

"We are witnessing an exponential increase in our knowledge of planetary systems in the universe and we now know some 10 exoplanets that could be suitable to host life," says Ignasi Ribas, director of the IEEC. "Of course, we have no clue whether life has thrived on the surface of those planets and if such lifeforms have developed intelligence. But we at IEEC are excited to participate in the experiment of sending an intentional message to the nearby habitable planet GJ273b and wait for a response. If that happened in 25 year's time, it would certainly be mind-boggling."

Of course, this isn't the first message humankind has sent to the stars. Our radio and TV signals have been beaming into space for about 100 years now, but we've also been making more deliberate attempts to broadcast our presence using radio transmissions or with Voyager's iconic Golden Record.

But there's another all-important question: Just because we can, does that mean we should? Scientists like Stephen Hawking have come forward in the past to say that not only should we not be broadcasting our existence to the cosmos, but we should be actively trying to hide it. After all, decades of sci-fi and millennia of human history have taught us that first contact between civilizations doesn't tend to go well.

It's mostly a publicity stunt for a music festival, but METI is dedicated to pinging ET one way or another. Either way, it's too late now: The Sónar Calling message is already zipping towards GJ273b at the speed of light, and all we can do is listen out for a reply in 2042.

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