MSN: According to the astronomers, signals from Earth would need to reach half of all the solar systems in the Milky Way in order to be picked up by an intelligent lifeform. by Anthony Cuthbertson via Newsweek
'Given that signals from TV and radio were first sent into space as a byproduct of broadcasting 80 years ago, it will take around 1,500 more years for aliens to receive, decode and respond to the signals.
'“We haven’t heard from aliens yet, as space is a big place—but that doesn’t mean no one is out there,” said Evan Solomonides, a co-author of the paper who will present it at the American Astronomical Society’s meeting on June 16 in San Diego.
'“It’s possible to hear any time at all, but it becomes likely we will have heard around 1,500 years from now. Until then, it is possible that we appear to be alone—even if we are not. But if we stop listening or looking, we may miss the signals. So we should keep looking.”'
"Possibility of alien contact could be 1,500 years away" by Daryl Lovell here