video: In the upper panel, the animation shows the average total power of individual airport radar systems, averaged over one-hour intervals. The lower panel reveals the total power of airport radar leakage radiation as a function of time, plotted over a 24-hour period in the direction of Barnard’s Star.
Credit: Ramiro Saide/Professor Michael Garrett
Royal Astronomical Society press release
RAS PR 25/24 (NAM 4)
8 July 2025
Embargoed until Tuesday 8 July 2025 at 16:00 BST
Radar systems used by civilian airports and military operations are inadvertently revealing our existence to potential advanced alien civilisations, new research shows.
The study 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. Theoretically, it also suggests this is how far we would be able to look to spot aliens who have evolved to use a similar level of technology.
Preliminary results revealed at the Royal Astronomical Society’s National Astronomy Meeting 2025 in Durham show how worldwide aviation hubs such as Heathrow, Gatwick and New York’s JFK International Airport give off clues to our existence.
By carefully simulating how these radar signals spread out from Earth over time and space, the researchers looked at how visible they would be from nearby stars such as Barnard's Star and AU Microscopii.
They found that airport radar systems, which sweep the skies for airplanes, send out a combined radio signal of 2x1015 watts, enough to be picked up as far as 200 light-years away by telescopes comparable to the Green Bank Telescope in West Virginia.
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 1x1014 watts in a given field-of-view of the observer.
This, lead researcher Ramiro Caisse Saide at the University of Manchester said, 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," the PhD student added.
"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."
He said 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 co-researcher Professor Michael Garrett, of the University of Manchester.
"The methods developed for modelling 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."
Caisse Saide, a PhD student, added: "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."
ENDS
Media contacts
Sam Tonkin
Royal Astronomical Society
Mob: +44 (0)7802 877 700
Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)7802 877 699
Megan Eaves
Royal Astronomical Society
Science contacts
Ramiro Caisse Saide
Manchester University
Professor Michael Garrett
University of Manchester
michael.garrett@manchester.ac.uk
Images & video
Caption: In the upper panel, the animation shows the average total power of individual airport radar systems, averaged over one-hour intervals. The lower panel reveals the total power of airport radar leakage radiation as a function of time, plotted over a 24-hour period in the direction of Barnard's Star.
Credit: Ramiro Saide/Professor Michael Garrett
Caption: This animation reveals the same average total power of individual airport radar systems and total power of airport radar leakage radiation as would be seen from AU Microscopii.
Credit: Ramiro Saide/Professor Michael Garrett
Caption: Radar systems used by civilian airports (like this at Heathrow) and military operations are inadvertently revealing our existence to potential advanced alien civilisations because of the hidden electromagnetic leakage they emit.
Credit: Mick Lobb / Radar scanner - Heathrow / CC BY-SA 2.0
Further information
The talk 'Examining Airport Civilian and Military Radar Leakage as a Detectable Marker for Extraterrestrial Civilizations' will take place at NAM at 15:05 BST on Tuesday 8 July 2025 in room TLC033.Find out more at: https://conference.astro.dur.ac.uk/event/7/contributions/245/
If you would like a Zoom link and password to watch it online, please email press@ras.ac.uk
Civilian airport radars and military radar systems, essential to any advanced civilisation's infrastructure, produce significant radio emissions that may be detectable across interstellar distances. The new research analyses 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.
Barnard's Star is one of the closest stars to our sun, at about six light-years away. The star is an extremely faint red dwarf that's about 3 per cent as bright as the Sun. It is named after the American astronomer E E Barnard, who measured properties of its motion in 1916.
AU Microscopii is a young red dwarf star located 31.7 light-years away from Earth. It is among the youngest planetary systems ever observed by astronomers.
Notes for editors
The NAM 2025 conference is principally sponsored by the Royal Astronomical Society and Durham University.
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