Every time you take off from Heathrow, land at JFK, or pass through any major airport, you might be inadvertently announcing humanity’s existence to alien civilizations up to 200 light years away.
New research reveals that the radar systems keeping our skies safe are simultaneously broadcasting powerful signals deep into space, signals that could serve as cosmic adverts of our very existence.
Ramiro Caisse Saide, a PhD student at the University of Manchester, led the research examining how Earth’s “hidden electromagnetic leakage” would appear to extraterrestrials equipped with radio telescopes similar to our own.
The findings, presented at the Royal Astronomical Society’s National Astronomy Meeting, suggest we’ve been accidentally transmitting technosignatures, or detectable signs of intelligent technology, for decades.
The numbers are staggering. Airport radar systems worldwide combine to send out radio signals totalling 2×10¹⁵ watts, powerful enough to be detected by telescopes comparable to the Green Bank Telescope in West Virginia at a distance of 200 light years.
To put this into perspective, that detection range encompasses over 120,000 stars, including potentially habitable worlds that could harbor alien civilizations with technology similar to ours.
It’s not just civilian aviation though, military radar systems create an even more distinctive signature, producing focused, directional beams that sweep across the sky like lighthouses, reaching peak emissions of about 1×10¹⁴ watts in specific directions.
The concept of technosignatures has revolutionised the search for extraterrestrial intelligence (SETI).
While traditional SETI focuses on detecting deliberate signals from alien civilizations, this research flips the perspective; what unintentional signals might we be leaking, and what similar leakage might we detect from other worlds?
The research examined how radar emissions would appear when observed from nearby star systems, including Barnard’s Star (6 light years away) and AU Microscopii (32 light years away), using sophisticated simulations of how the signals spread through space over time.
The results reveal distinct patterns that depend on both the global distribution of radar installations and the observer’s location relative to Earth.
This work builds on Saide’s previous research showing that signals from mobile phone towers could be detectable up to 10 light years away.
Airport radar reaches much further because these systems are specifically designed to scan large volumes of airspace continuously.
The combined effect creates a radio signature that varies as Earth rotates, with different radar installations rising and setting from an alien observer’s perspective.
For SETI researchers, this represents a different search strategy. Rather than only listening for intentional messages, scientists can now look for the technological exhaust of civilizations going about their daily business; managing air traffic, conducting military operations, or maintaining the infrastructure of a space faring society.
The research suggests that radar signals, produced unintentionally by any planet with advanced technology and complex aviation systems could act as a universal sign of intelligent life.
This universality is key since any civilisation sophisticated enough to develop air travel and radar technology would likely produce similar electromagnetic signatures.
The closest potentially habitable exoplanet, Proxima Centauri b, lies just 4.2 light years away which is well within the detection range of our radar leakage.
If aliens exist there with technology matching our own, they could already be aware of our presence. Similarly, if comparable civilizations exist around any of the thousands of stars within 200 light years, we might soon detect their airport radar too.
As Saide concludes, this 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”. The next time you board a flight, remember, your journey might be visible to our neighbours across the Galaxy.
Written by Mark Thompson/Universe Today.
