In a new study, a team of researchers from the University of Manchester performed comprehensive simulations of Earth’s radar systems as potential technosignatures detectable by extraterrestrial observers. While SETI traditionally focuses on deliberate transmissions, the scientists examined unintentional electromagnetic leakage from civilian airport radars and military radar systems. These technologies, essential to any advanced civilization’s infrastructure, produce significant radio emissions that may be detectable across interstellar distances. The authors analyzed how the global distribution of radar installations affects the temporal structure of Earth’s radio signature when observed from six specific stellar systems: Barnard star, HD 48948, HD 40307, AU Microscopii, HD 216520, and LHS 475. Their results reveal distinct patterns in radio leakage that depend on both terrestrial radar distribution and observer location, providing valuable insights for future SETI strategies. The findings suggest that radar systems, represent among the most detectable unintentional technosignatures of technological civilizations, offering a promising avenue for extraterrestrial intelligence detection.
Ramiro Saide et al. explored how hidden electromagnetic leakage might look to extraterrestrials up to 200 light-years from Earth, if they had state-of-the-art radio telescopes like our own. Image credit: Gemini AI.
“We found that airport radar systems, which sweep the skies for airplanes, send out a combined radio signal of 2*1015 watts, enough to be picked up as far as 200 light-years away by telescopes comparable to the Green Bank Telescope in West Virginia,” said University of Manchester Ph.D. student Ramiro Caisse Saide and his colleagues.
“To put that distance into context, the nearest potentially habitable world beyond our Solar System is Proxima Centauri b, which is 4 light-years away.”
“That would still take a spacecraft using current technology thousands of years to get there.”
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.
“This would look clearly artificial to anyone watching from interstellar distances with powerful radio telescopes,” Caisse Saide said.
“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.”
“Our findings suggest that radar signals — produced unintentionally by any planet with advanced technology and complex aviation system — could act as a universal sign of intelligent life.”
The research not only helps guide the search for extraterrestrial civilisations by identifying promising technosignatures, but also deepens our understanding of how human technology may be seen from space.
“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,” said University of Manchester’s Professor Michael Garrett.
“The methods developed for modeling and detecting these weak signals can also be used in astronomy, planetary defence, and even in monitoring the impact of human technology on our space environment.”
“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,” Caisse Saide said.
The researchers presented their results today at the Royal Astronomical Society’s National Astronomy Meeting 2025 in Durham, the United Kingdom.
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Ramiro Saide et al. Examining Airport Civilian and Military Radar Leakage as a Detectable Marker for Extraterrestrial Civilizations. NAM 2025
