Aliens can detect Earth's airport from 200 light years away

Humans may not know of any intelligent extraterrestrial beings , but if they exist, they probably know about us. New research suggests that radar systems at commercial and military airports are inadvertently broadcasting humanity's presence to any aliens who might be listening.

Preliminary results from a study led by Ramiro Caisse Saide, a PhD student in astrophysics at the University of Manchester, suggest that aliens up to 200 light years away could theoretically detect electromagnetic signals leaking from global aviation hubs like John F. Kennedy International Airport in New York and Heathrow Airport in London. Military radar systems could also detect them, and thanks to their unique patterns, these signals would 'look obviously fake to anyone observing from interstellar distances with a powerful radio telescope ,' Caisse Saide said in a statement.

' In fact, these military signals can be hundreds of times stronger from certain points in space, depending on the observer's location, ' he said. ' Our findings suggest that radar signals – generated unintentionally by any planet with advanced technology and complex aeronautical systems – could serve as telltale signs of intelligent life .'

However, it is important to note that it will take many years for the signal to reach any extraterrestrial civilization located more than 200 light years away. Airports and military operations have only been emitting signals of this magnitude since the 1950s, so the maximum distance at which aliens could currently detect them is about 75 light years in any direction.

Since we live in an ancient, incredibly vast universe with trillions of planets and moons, it makes sense that humans are not the only intelligent life forms. Humanity's desire to communicate with aliens dates back more than 150 years. The first real attempt at communication took place in 1974, when astronomers transmitted a radio signal from a powerful transmitter at the Arecibo Observatory in Puerto Rico into space. The signal, known as the Arecibo message, consisted of binary code that conveyed information about the basic chemicals of life, the structure of DNA, Earth's location in the solar system, and even a stick figure. If any aliens received it, they did not respond.

That hasn't discouraged scientists from looking for them. Those working in the Search for Extraterrestrial Intelligence (SETI) program do so passively, scanning space for electromagnetic signals that can't be explained by natural phenomena. Others have taken a more proactive approach, actively broadcasting signals or messages into space, like the Arecibo message. These efforts are called METI (Messages to Extraterrestrial Intelligence) or CETI (Communications with Extraterrestrial Intelligence). Not everyone is convinced this is a good idea. Critics point out that telling aliens where we are could have dire consequences if these beings were capable of causing harm to humans or Earth.

It's a scary thought. Perhaps even scarier is the idea that Earth might inadvertently reveal our existence and location to any alien civilization with radar within earshot. To understand how noisy our planet is, Caisse Saide and colleagues simulated how radar signals from airports propagate through time and space, then analyzed how easily they would be detected by stars like Barnard's Star and AU Microscopii. These stars are about 6 and 32 light years from the Sun, respectively.

Lesley Montoya

Update 15 July 2025