New research reveals that civilian and military radar systems emit radio signals strong enough to be detected from hundreds of light years away – and could reveal our existence to intelligent civilizations
Radar systems at airports and in military applications may expose us to alien observers across the galaxy.
Credit: SciTechDaily.com
New research shows that radar systems operated at civilian airports and military facilities may be inadvertently broadcasting Earth's presence to technologically advanced alien civilizations.
The researchers looked at how electromagnetic signals leaking from these systems might appear to observers 200 light-years away, assuming they had advanced radio telescopes similar to those used on Earth. The findings also suggest that we could, theoretically, detect equally advanced alien civilizations at the same distance.
The initial findings show how major international airports, including Heathrow, Gatwick and JFK in New York, emit detectable signals that could serve as indirect indicators of intelligent life.
The simulations mimic the visibility of the signals.
At the top, the animation shows the average total power of radar systems at specific airports, averaged over one-hour intervals. The bottom shows the total power of radiation leaking from airport radars as a function of time, over 24 hours, in the direction of Barnard's Star. Credit: Ramiro Saide/Professor Michael Garrett
The researchers used detailed simulations to track how radar signals emitted from Earth move through space over time. The goal was to determine to what extent these signals could be detected from nearby star systems, such as Barnard's Star and AU Microscopii.
Their analysis shows that airport radar systems, designed to monitor aircraft, produce a combined radio power of 2×10¹⁵ watts. This level of emission is strong enough to be detected up to 200 light-years away by radio telescopes with capabilities similar to those of the Green Bank Telescope in West Virginia.
For perspective, Proxima Centauri b – the closest potentially habitable exoplanet – is only four light-years from Earth. Even so, a spacecraft powered by current technology would still take several thousand years to reach it.
Military radars are more detectable
Military radar systems, which are more focused and directional, creating a unique pattern – like a lighthouse beam scanning the sky – have a cumulative peak emission of about 1×1014 and in a given field of view of the observer.
Is the Earth broadcasting its location unintentionally?
This, said study director Ramiro Cais Said, "is clearly artificial to anyone observing from interstellar distances using powerful radio telescopes. In fact, these military signals can appear up to a hundred times stronger than certain points in space, depending on where the observer is."
Technology signatures and the implications for S
"Our findings suggest that radar signals – which are unintentionally produced on any planet with advanced technology and a complex aviation system – could serve as a universal sign of intelligent life."
He said the research not only helps guide the search for extraterrestrial civilizations by identifying promising technological signatures, but also deepens our understanding of what human technology might look like from space.
"When we learn how our signals travel through space, we gain important insights into how to protect radio frequencies for communications and design future radar systems," said co-investigator Professor Michael Garrett.
"The methods developed for modeling and detecting these weak signals can also be used in astronomy, planetary defense, and even for monitoring the impact of human technology on our space environment."
The paper was presented at the 2025 World Astronomical Union conference.
More of the topic in Hayadan:
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How about hundreds? When radar started about 100 years ago.
Radio signals at about the speed of light.
Maybe we reached 100 plus or minus a few years.
Yes, but there is a quantitative calculation here.
This is pretty basic information and not new, as soon as we moved into the electronic age, antennas, television, we started broadcasting ourselves to the universe.