In 1977 NASA's Voyager 1 and 2 spacecraft launched into space carrying phonographs called the Golden Records containing pictures and sounds meant to show extraterrestrials a glimpse of life on Earth. The records were engraved with pictures explaining how to play them. Click on the picture for an explanation of the code.
When E.T. sends us Earthlings a message, what should we say in response? Three alien hunters suggest in the journal Space Policy that we should develop an international protocol for sending effective, intelligible communications. A website could be set up for people around the world to leave messages, following the protocol, so that we can then figure out what messages are best-suited for cross-cultural communication.
"An effective message to extraterrestrials should at least be understandable by humans," Dimitra Atri of the University of Kansas, Julia DeMarines of the International Space University, and Jacob Haqq-Misra of Penn State University write in their paper.
The concept of creating and testing such a protocol fits with the thinking of other space experts, according to Douglas Vakoch, director of interstellar message composition at the California-based SETI Institute.
This graphic was transmitted in coded form in 1974, using the Arecibo radio telescope. Click on the picture for an explanation of the code.
The proposal from the three researchers "is on target in really wanting to encourage an open, transparent process for engaging the world community in thinking about how we would want to represent ourselves, and how we would create a message that stands a chance of being understood," Vakoch told me today.
Talking to E.T.
Unless E.T. comes to Earth in a spaceship and gets out for a meet-and-greet, the chances of a face-to-face encounter anytime soon are close to nil. Instead, cross-civilization communication will have to span vast distances, using technology such as radio waves and pulses of light.
Astronomers on the lookout for these types of communications have already established protocols for making sure a communication received isn't just a natural noise or interference from a satellite. They've also established first-order steps to decipher the message, such as determining the basic units of the information sent.
This same community of researchers has also spent the past 50 years chewing on the question of what to say to E.T. The trick, noted Vakoch, is finding something that is universal.
"Some have focused on pictures, with the idea that vision has been very helpful here on Earth and so too might be helpful on another world," Vakoch said. "You might expect intelligent creatures on another world to be visual creatures as well."
But what may be a meaningful picture to a person from a Western culture may be gibberish to the indigenous Maori people in New Zealand, for example.
"Similarly, a Westerner may look at some ceremonial carving from the Maori and say, 'You know, that's a beautiful geometrical shape,' but a Westerner may miss the fact that there's a human body being depicted in that message," Vakoch said.
Another idea is to use basic math and science. After all, if alien beings are able to communicate with us, they must have the engineering and technical know-how required to send messages across interstellar distances.
"I think the key to creating a message that has a reasonable chance of being understood is to send as many distinct messages as you can, with the hope that at least one of them might be understood," Vakoch said. "Anyone who claims they have one message that will undoubtedly be understood is overly optimistic."
The Space Policy paper calls for setting up a website where users around the world can submit messages that fit the protocol. This will allow the discovery of "the types of messages better suited for cross-cultural communication," the authors write.
The SETI Institute's Earth Speaks project is built along these lines, notes Vakoch. The website solicits suggestions for the most important things that people want E.T. to know about life on Earth at the beginning of the 21st century.
Vakoch said the idea proposed in the Space Policy paper is complementary and attracts another audience to mull the questions surrounding what to say to E.T. "We need more people involved in space policy to be thinking about these issues," he said.
More on the alien quest:
- E.T. calling? Here's what to do
- How should we 'talk' to aliens?
- What to do if we find alien life
- Are we missing E.T.'s call?
- Calculate the odds of finding E.T.
- Stephen Hawking worries about the aliens
- Too risky to phone E.T.? Too late — NASA's tried
- Six frontiers for extraterrestrial life
Tip o' the Log to Lisa Grossman at Wired.com.
John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).