Radar from airports and military systems may expose Earth to alien detection.
These signals could be used to find intelligent civilizations.
Research indicates that radar systems operated by both civilian airports and military facilities may be unintentionally broadcasting Earth’s presence to technologically advanced alien civilizations.
Investigation examined how electromagnetic signals that leak from these systems could appear to observers located as far as 200 light-years away, assuming they possess advanced radio telescopes comparable to those used on Earth.
The findings also imply that we could, in theory, detect similarly advanced alien civilizations within the same range.
Initial findings, presented at the Royal Astronomical Society’s National Astronomy Meeting 2025 in Durham.
Highlight how major international airports, including Heathrow, Gatwick, and New York’s JFK, emit detectable signals that could serve as indirect indicators of intelligent life.
Simulations trace signal visibility
The researchers used detailed simulations to track how radar signals emitted from Earth travel through space over time.
Their goal was to determine how detectable these signals would be from nearby stellar systems, including Barnard’s Star and AU Microscopii.
Analysis showed that airport radar systems, designed to monitor aircraft, generate a combined radio output 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 the Green Bank Telescope in West Virginia.
For perspective, Proxima Centauri b—the closest potentially habitable exoplanet—is located just 4 light-years from Earth.
Even so, a spacecraft powered by current technology would still require several thousand years to reach it.
Military radars are more detectable
Military radar systems, which are more focused and directional, create a unique pattern – like a lighthouse beam sweeping the sky – have an accumulated peak emission reaching about 1×1014 watts in a given field-of-view of the observer.
