A new study has investigated whether alien civilizations could find humanity by detecting radio signals from cell phone towers leaking from Earth.
The team simulated leakage from cell towers around the world, attempting to work out if advanced aliens around nearby stars would be able to detect it using equipment equivalent to what we have on Earth.
"In terms of detectability, we conclude that any nearby civilization located within 10 light-years of Earth and equipped with a receiving system comparable to the GBT [Green Bank radio telescope] would not detect the Earth’s mobile tower leakage," the team concluded.
In turn, using current Earth technology, we would not be able to detect alien lifeforms leaking similar signals.
"However, mobile systems are in their infancy, and the future development of this technology (e.g. 5G systems and beyond) suggests that this component of the Earth’s leakage will continue to increase in power over time," the authors write in their paper. "If the leakage can be detected, an extraterrestrial observer would be able to discern various details of the nature of our planet and the distribution of technology on its surface."
This would include being able to create a model of Earth showing the distribution of land, vegetation, oceans, and ice, according to the team.
“I’ve heard many colleagues suggest that the Earth has become increasingly radio quiet in recent years - a claim that I always contested," lead author Professor Mike Garret, director of Jodrell Bank Centre for Astrophysics at the University of Manchester, said in a statement.
“Although it’s true we have fewer powerful TV and radio transmitters today, the 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."
Aliens with more advanced listening equipment would of course have more of a chance of catching our stray signals, and the odds of this happening increases as our own technology progresses.
“Current estimates suggest we will have more than one hundred thousand satellites in low Earth orbit and beyond before the end of the decade," Garrett added. "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”.
The study is published in Monthly Notices of the Royal Astronomical Society.