The messages would be sent to Gliese 581d, a water-covered world eight times the size of Earth, COSMOS Magazine said. The planet, 20 light years from Earth, is the closest Earth-type planet discovered so far.
"It's like a 'message in a bottle' cast out into the stars," said Wilson da Silva, editor of COSMOS. "What's interesting is not just whether there's anyone listening, but what the public will say to intelligent life on another planet, given the opportunity."
The project is part of Australia's National Science Week, with those interested in speaking to the galaxy asked to log on to www.HelloFromEarth.net before 5 p.m., Aug. 24, Sydney time. Messages are limited to 160 characters.
The messages will be beamed Aug. 28 to Gliese 581d from the Canberra Deep Space Communication Complex, in Tidbinbilla.
No replies are likely before 2051, unless the residents, if any, of Gliese 581d have discovered a faster means of interstellar communication.