FACTBOX: Talking to aliens

LONDON (Reuters) - The Search for Extra Terrestrial Intelligence (SETI) project, founded in California in 1984, makes the assumption that any alien civilization that does make contact will be vastly more advanced than ours.

Purely statistically, its scientists say, the chance of two relatively short-lived civilizations like our own making contact is remote -- much more likely that any race emitting signals that we can intercept will have been at it for some time.

What then, should one say in reply?

Douglas Vakoch, Director of Interstellar Message Composition at the SETI Institute, says we should be honest.

In 1977, the first Voyager spacecraft was launched with over 100 pictures and drawings depicting the human race in case it should ever encounter any other intelligent life forms as it heads out into the vastness of space.

But they were all positive images of mankind. Nowhere, notes Vakoch, were there any depictions of the dark side like poverty, war or environmental blight.

"Presenting the positive side of life on Earth in the Voyager recordings was a natural attempt to put our best foot forward," he wrote in a paper in April.

"But, I would argue, perhaps the most important contribution we could make in an interstellar conversation would be to acknowledge those parts of ourselves that we are least proud of."

Older beings, he says, will have made their way through the "bottleneck of technological adolescence" where a civilization's self-destructive capacity outweighs its social maturity.