What's the proper conversation starter when greeting an alien?
How about, "This is Earth speaking. We would like to know you. Please reply."
Less graciously but perhaps more honestly, you might offer, "Down here we are all confused."
And by the way, if you do come for a visit, please "don't kidnap us and poke us. We hate that."
These are all authentic, if occasionally crack-brained, suggestions for how we might go about opening a dialogue with an alien civilization.
During the last few decades, the search for life beyond our planet has focused almost exclusively on trying to find a signal in space from an intelligent civilization. Such searches are becoming increasingly sophisticated.
The SETI Institute, the world's best-known organization dedicated to the search for alien life, recently unveiled plans to scan a million stars over 10 billion communication channels at its Hat Creek radio telescope facility north of Sacramento.
Now, the private Bay Area organization has launched a companion project called Earth Speaks that asks space enthusiasts around the world to think about what we should say when, or if, we finally get that cosmic phone call.
"Most conversations about this subject until now have been among academics," said Douglas Vakoch, who is heading up the new effort at SETI, which stands for the Search for Extraterrestrial Intelligence. "We want to really expand the discussion."
Center director Jill Tarter, a lifelong alien hunter on whom the Ellie Arroway character from the movie "Contact" was based, said there is no simple answer. But it is vital, she said, that there be a global consensus on what we say and do before it happens.
Based on the first few hundred suggestions collected by the Earth Speaks website, that consensus might be elusive. So far, the messages break down into a few distinct categories. Some people want to throw a block party to welcome the aliens to the neighborhood. Others, less trusting, would warn the aliens that we've got guns and know how to use them.
Another group, possibly influenced by having seen too many movies, would have us hide under the bed until they go away. "If we discover intelligent life beyond Earth, we should not reply -- we should freeze and play dead," wrote one contributor.
There is a fourth category of people who refuse to take the whole idea seriously. One tongue-in-cheek writer suggests we broadcast, "There's nothing to see here. Move along."
SETI has no plans to actually send the messages into space. Vakoch said that before anything like that is undertaken, it should be subject to international discussion.
The first serious effort to contact intelligent life outside Earth was made in 1974, using the big radio telescope at Arecibo, Puerto Rico. The three-minute transmission by a group at Cornell University attempted to describe Earth and its inhabitants in binary code.
Over the last few years, a Russian group has sent greetings in Russian and English to targeted stars in our galactic neighborhood, generating a major dust-up in the small but passionate SETI community. Critics say the Russians are acting out of turn, without asking permission to open what would amount to diplomatic relations with another civilization. The problem is that nobody has the authority to grant permission.
Some observers say there is no need for us to broadcast a message. We're already doing that in the form of leakage into space of our radio and television signals. Those signals, however, are much too weak to travel far. A coordinated communications effort would require a powerful transmitter, a highly focused beam and a receiver pointed in the right direction.
Tarter acknowledged that there is plenty of reason to be cautious about replying to an alien signal.
"We're in an asymmetric position," she said. "We don't know if there are other civilizations out there, but if there are, we can be pretty sure we are the youngest." And, therefore, the most vulnerable.
Earthlings have had the technology to broadcast and receive electromagnetic waves for about a century. But the galaxy has been around for billions of years.
Any civilization that contacts us is likely to be much older.
"As the new kids on the block, we should listen first" and reply later, Tarter said.