No, no, that's not what we meant...
The Long Now blog points out some home truths about our quest for extra-terrestrial intelligence by sending messages into space. In 1974, the Arecibo message was targeted at a star cluster 25,000 light years away, which makes for an awfully long wait for any kind of reply.
I love this idea of sending a message to another intelligent lifeform, having it take 25,000 years to get there, and then a further 25,000 years for the reply to reach us. At which point, in the year 51974, we say "No, no, that's not what we meant..." and it all begins again.
Because the 'we' in 51974 will not be the same people we were in 1974. Though we'll probably still be watching repeats of Man About the House.
