According to experts, extraterrestrial civilizations could use signals from mobile phone masts in order to locate planet Earth. The number of mobile phone towers in the past 30 years has exponentially skyrocketed, making it the second most powerful source of Earth's radio leakage. Let's take a closer look.
Basically, each mobile tower can emit a radio signal with 100 to 200 watts, which is equal to four gigawatts from our planet. According to researchers from the University of Manchester and the University of Mauritius, if an alien had a radio telescope equal to the Square Kilometre Array, then they could have the capabilities to detect our 4G activity down on Earth. The SKA is a collaborative effort between South Africa and Australia to create the world's largest radio telescope and will allow scientists to study the universe in new detail and with completely new lenses, literally. Researchers Dr. Nalini Heeralall-Issur, from the University of Mauritius, said, "I believe that there's every chance advanced civilizations are out there, and some may be capable of observing the human-made radio leakage coming from planet Earth."
Researchers also believe they need to be within eight lightyears of Earth for it to be possible. Experts think they need a powerful enough telescope, and where they are in the sky would affect their ability to get an accurate signal. A planet with extraterrestrial life would get less of a signal in the southern hemisphere than in the northern hemisphere because mobile towers release radio power parallel to the surface of the Earth. So, the signal is most powerful when it is rising or setting across the horizon.
However, these potential aliens would not necessarily be able to listen in to our conversations-so don't worry! The research shows that extraterrestrial life would be able to measure planet Earth's land distribution and watch how the population changes over time. Researchers also determined extraterrestrial civilization would be able to determine the planet's rotation and axial tilt. However, the main goal of the study was to "determine the power spectrum of mobile towers on Earth as observed by a hypothetical civilization located at interstellar distances."