Can ET Hear Us?

Radio telescopes around the world are listening for the whispers of other civilizations. That includes the Very Large Array — a set of 27 radio dishes that acts as a single giant telescope.

The VLA is conducting a survey of most of the sky. And a few months ago, scientists who are hunting for civilizations in other star systems began tapping into that survey. They’re looking at narrow sets of frequencies that are the most likely to have an intelligent origin.

Scientists also are pondering whether other civilizations could hear us. We produce a constant radio “haze,” including the drone of billions of cell phone calls. And a team recently looked at whether any close-by civilization might be able to “eavesdrop” on those calls.

The team looked at the radio waves that leak into space from some of the most powerful cell-phone towers. It calculated whether that leakage could be picked up by Earth-like radio telescopes at three nearby star systems, including the two closest, Alpha Centauri and Barnard’s Star.

The team found that the signals fade away before they reach any of those stars — you’d need more advanced technology to hear them. But the team is extending its work to include other types of Earthly transmissions, including military radar, orbiting satellites, the network that talks to deep-space missions, and future cell towers. That should tell us whether Earth is loud enough to be heard by ET.
 

Script by Damond Benningfield