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. 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.