While we work hard to search for extra-terrestrial life beyond our planet, radiation leaked from Earth’s mobile towers could be helping aliens find us. Put your tinfoil hat away: this isn’t anything to do with 5G. And the radiation being leaked isn’t the cancer-causing kind – it's the same type of energy used in radio and TV signals.


New research shows that this radio leakage from mobile towers is not currently strong enough on its own to be detectable by alien civilisations – assuming they are using the same technology as we are to find them. But if aliens have more advanced systems and are looking at radiation from more sources – such as Wi-Fi networks – we could soon be discovered by extra-terrestrials living on nearby stars.

“I believe that there’s every chance advanced civilisations are out there, and some may be capable of observing the human-made radio leakage coming from planet Earth,” says The University of Mauritius’ Dr Nalini Heeralall-Issur – a co-author of the paper. Our information about the habitability of exoplanets is constantly growing thanks to insights from satellites, the James Webb Space Telescope, and space missions like the JUpiter Icy moons Explorer (JUICE).

While the research found that only technologically advanced alien civilisations would be able to detect our mobile leakage, the researchers from The University of Manchester and The University of Mauritius claim that most alien civilisations are likely to have more sensitive receiving systems than ours.

As our broadband systems become more powerful, our detectability is likely to increase even further. For any aliens out there, these so-called ‘techno-signals’ (signals generated artificially, rather than in the natural world) would emanate primarily from heavily populated parts of our planet’s northern hemisphere, where most of our transmissions take place.

Published in the Monthly Notices of the Royal Astronomical Society journal, the study used data from mobile towers to simulate the radio leakage that could be detected from various nearby stars if using the USA’s Green Bank Telescope.

This includes Barnard’s star, which belongs to a system six light years away from Earth that contains potentially habitable planets, as well as HD 95735 and Alpha Centauri A.

Despite claims that the Earth has been getting increasingly ‘radio quiet’, project leader Prof Mike Garrett from the University of Manchester said that modern “proliferation of mobile communication systems around the world is profound. While each system represents relatively low radio powers individually, the integrated spectrum of billions of these devices is substantial.”

While TV transmission leakage has weakened since the advent of cable and internet TV, Earth’s ‘radio leakage signature’ now consists of strong mobile radio signals as well as other kinds of signals, such as radars, digital broadcast systems and Wi-Fi networks.

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Plans for numerous satellite constellations, including Elon Musk’s Starlink, are also likely to increase our likelihood of being detected. “Current estimates suggest we will have more than one hundred thousand satellites in low Earth orbit and beyond before the end of the decade,” says Garrett.

Simulating the detectability of these signals will be the next step for the research team behind the new study. According to Garrett, “the Earth is already anomalously bright in the radio part of the spectrum; if the trend continues, we could become readily detectable by any advanced civilisation with the right technology.”

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Noa LeachNews editor, BBC Science Focus

Noa Leach is the News editor at BBC Science Focus. With an MPhil degree in Criticism & Culture from the University of Cambridge, Noa has studied cultural responses to the climate crisis, wildlife, and toxicity. Before joining BBC Science Focus, Noa was the Editor of The Wildlife Trust BCN’s magazine Local Wildlife. Her writing has been shortlisted for the Future Places Environmental Essay Prize.