When the Breakthrough Listen initiative was launched, so too was a sister project called Breakthrough Message. This is a competition to write a digital message to an alien civilisation, with prizes totalling $1m (£660,000).
However, there are no current plans to send these messages. “We pledge not to transmit any message until there has been a wide-ranging debate at high levels of science and politics on the risks and rewards of contacting advanced civilisations,” say the organisers.
Stephen Hawking is one of many scientists to caution against sending unsolicited messages out into the Universe. Instead, the organisers want to inspire us to think about what information best represents humanity and how it might be presented in a way that an alien civilisation could understand.
So what should go into such a message? We can get some idea by looking at previous attempts at communication.
When the Voyager probes were launched in 1977, the craft carried with them gold-plated 12-inch copper discs containing sounds and images from Earth. Alongside recordings of birdsong, waves and thunder sits music by Bach, Beethoven and Chuck Berry. The images included depict our Solar System, DNA and how we reproduce. There’s also a map showing our location with respect to several loud pulsars in the Milky Way. Voyager 1 may have left the Solar System, but it will be 40,000 years until it reaches another star system.
The Arecibo message, beamed towards globular cluster M13 on 16 November 1974, is another example of messages we have sent into space. This short radio broadcast contained key information about the human race encoded into binary. The numbers one to 10 appear alongside information about DNA, a depiction of the human body and illustrations of the Solar System. But as M13 is 25,000 light-years away, the message won’t be arriving soon.
That’s another consideration – it takes an incredibly long time for signals to travel through space. Even travelling at the speed of light, it would be four years before any radio message we sent arrived at our nearest solar system. KIC 8462852, the star at the heart of the megastructures mystery, sits nearly 1,480 light-years away: any reply to a message we sent there today wouldn’t arrive for 3,000 years.
So a related problem is how to depict ourselves, our way of life and our technology in a way that will still be representative in the centuries to come. Some modern commentators have pointed out that the information despatched by Voyager 1 showed a civilisation dominated by white Western males. Perhaps the next time we choose to send information into space, it will be more representative of us all.