Voyager NASA
Undated artist\'s concept depicting NASA\'s Voyager 1 spacecraft entering interstellar space Reuters

A campaign has been launched encouraging members of the public to write a message that will be sent billions of miles from earth in the hope that an alien civilisation will discover it. The Voyager 1 and 2 probes were launched into space in 1977 with a mission to explore the outer reaches of our solar system and send back pictures of planets and their moons.

But now they are edging towards interstellar space carrying so-called "golden records", which contain music, greetings, sounds and pictures. The records are designed to express our humanity and culture giving any unsuspecting alien life form a snapshot of the human race.

But the golden records are almost 40 years out of date, circa 1977, so Professor Christopher Riley, at the University of Lincoln's School of Film & Media, is launching a global call to action, beginning on Facebook to crowd-source a short final message. Once selected he will invite NASA to send the message to the Voyagers and then into the rest of the galaxy.

The final message should be no more than 1,000 characters long and, as of 31 October, we have just 2,922 days until we lose contact with the voyagers because the on board electrical power will eventually run out. But the two probes will carry on, eventually leaving the Solar System to drift through the galaxy for another billion years.

Prof Riley said: "Before the Voyagers power down, why not add one final message from planet Earth, as a digital postscript to these most remarkable time capsules of humanity? There's really no reason why a message can't be written by an impartial representative from the human race, so we're inviting suggestions from anyone who would like to contribute a thought.

"We're inviting NASA to transmit a final message from humanity to the Voyager 1 & 2 spacecraft and we'd like you and your friends to contribute a suggestion of what it should say," he told Sky News.

The Golden record
The Golden Record that each of the Voyagers are carrying NASA

The campaign, which is not affiliated to NASA, concedes that a message has a very low chance of being heard by another life form. They say on their website: "It is very unlikely that the Voyagers will ever be intercepted by another space faring civilisation.

"Results from the SETI program, which has searched for signs of intelligence technological civilisations in our galaxy for the last 50 years or more now suggest that such intelligent technological life is probably quite rare.

"But should they ever be found, and the Golden Record decoded and interpreted, then it's possible that their computer memories might also be able to be read by such smart and resourceful enough beings."

But despite Prof Riley's attempts to engage the public, another academic has poured scorn on the idea. Dr Anders Sandberg, a research fellow at Oxford University's Future of Humanity Institute, said it should left well and truly alone for the fear of confusing the message.

"I think it's a mistake to update the information," he said. "The Voyager probes are time capsules. They were sent off in the late 1970s and reflect the world as it was back then.

"We can't really add much to a message by adding 1,000 letters to it. But it's actually possible to destroy a message or change its meaning.

"If I send you a message and later send a: 'Ha ha, just kidding', I might actually change the meaning of what I've previously sent. I think it's not a good idea to update it - just let them go."

But Prof Riley said he believes there is little risk of confusing the message. He said: "There is no risk of being misunderstood or changing the meaning of the existing golden record. It is a wonderful opportunity we mustn't miss."

The Facebook group is entitled Voyager's last message and has been liked by 115 people.