We may already be broadcasting signals to the universe and alien life that inadvertently scream “we’re here, come find us!”  —  and any potential intelligent life in the universe could be sending the same inadvertent message to us!
Military and civilian radar signals could be a beacon for advanced alien life, indicating the presence of intelligent life on Earth. That’s according to new research that suggests that “hidden electromagnetic leakage” could be visible to aliens up to 200 light-years away that might possess state-of-the-art radio telescopes like ours.
Of course, this works both ways, potentially suggesting how far out in the cosmos we could hunt aliens that broadcast similar signals on their home worlds.
“Our findings suggest that radar signals – produced unintentionally by any planet with advanced technology and complex aviation systems – could act as a universal sign of intelligent life,” team leader and University of Manchester researcher Ramiro Caisse Saide said in a statement. “In this way, our work supports both the scientific quest to answer the question ‘Are we alone?’ and practical efforts to manage the influence of technology on our world and beyond.”
“Come in Proxima Centauri b, this is humanity…”
The team’s research suggests that worldwide aviation hubs such as O’Hare International Airport in Chicago, John F. Kennedy International Airport in New York, and Heathrow Airport in London, among others, could give off clues to our existence.
The team behind the findings determined this by simulating how terrestrial radar signals from these installations spread out from Earth as they travel through space.
They then considered how detectable these signals would be from relatively nearby stars such as the red dwarf Barnard’s Star, the fourth nearest star to Earth at 5.96 light-years away, and AU Microscopii, located 31.7 light-years from our planet.
This revealed that airport radar systems, which sweep the skies for airplanes, send out a combined radio signal strong enough to be picked up as far as 200 light-years away by telescopes comparable to the Green Bank Telescope in West Virginia.
The closest potentially habitable world to Earth is Proxima Centauri b, which is 4 light-years away, meaning that if it hosts intelligent life with radio telescopes, those telescopes could detect our leaked signals.
Of course, the chances of a visit would still be slim. Even if (and that is a huge “if”) the occupants of Proxima Centauri b had spacecraft more advanced than ours, it would still take many thousands of years to traverse this distance.
Detecting military radar signals is a different proposition. These signals are more focused and directed and create lighthouse-like beams that sweep across space.
Caisse Saide pointed out that as a result of this, military signals would look “clearly artificial to anyone watching from interstellar distances with powerful radio telescopes.
“In fact, these military signals can appear up to a hundred times stronger from certain points in space, depending on where an observer is located.”
In addition to suggesting what astronomers could look out for as they scan the skies for intelligent life, the research could help to perfect terrestrial radar systems.
“By learning how our signals travel through space, we gain valuable insights into how to protect the radio spectrum for communications and design future radar systems,” team member and University of Manchester professor Michael Garrett said. “The methods developed for modeling and detecting these weak signals can also be used in astronomy, planetary defense, and even in monitoring the impact of human technology on our space environment.”
The team’s research was presented on Tuesday (July 8) at the Royal Astronomical Society National Astronomy Meeting (NAM) 2025 at Durham University in the UK.
