Advanced Alien Civilizations Could Detect Earth's Technological Signatures

Tuesday - May 16 2023, 23:05 UTC - 1 year ago

This study provides a clue on the possibility of an advanced alien civilization detecting Earth's technological signatures, which can be observed with the advent of mobile phones, and can relay information on where the landmasses are on our planet and the small nature of our civilization.

Are we alone in the universe? It's a question that fascinates scientists and the public alike. In science, the focus tends to be on our search for life elsewhere. The idea that we might be watched by a distant alien civilization, however, is usually confined to the realm of science fiction.

But if there are other technological civilizations out there, they would probably be significantly more developed than we are. After all, we have only just emerged as a fledgling technical (industrial) civilization in the last 200 years—other technical civilizations could easily be 1,000 or 10,000 or even 100,000 years more advanced than we are.

And no one can deny that the pace of our own technological progress is accelerating, in some areas at a blistering pace. To paraphrase science fiction author Arthur C. Clarke’s third law—an advanced civilization would appear to us as capable of magic in terms of their technical prowess.

Over the last few years, my colleagues and I have started to think about whether an advanced civilization could detect the technological signatures ("techno-signatures"), such as radio emissions, from Earth. And if so, what might they detect? .

Our latests study provides a clue.

This isn’t the first time such research has been undertaken. But it’s now more than 50 years since the topic was properly considered. While a lot has changed since the mid-1970s, by far the biggest change has occurred in the last two decades with the advent of mobile phones. These devices and the towers that connect them have created a new broadband radio emission techno-signature.

Although 4G mobile handsets and transmitting towers are relatively low power individually (0.1-200 watt), there are just so many of them—billions of phones and many millions of towers. And the accumulated radio emission from these is beginning to become quite significant. But would it be noticeable to an alien civilization watching from afar? We wanted to find out.

It turns out to be rather difficult to find a public database that lists the location and transmitting characteristics of all the mobile towers around the world. But by using the OpenCellID database, with data populated by crowdsourcing, we were able to build a simple model estimating the global distribution of mobile towers.

Our model is no doubt crude and incomplete, but it is our best estimate of the techno-signature mobile towers leak out into space.

Because the Earth rotates on its axis, an advanced civilization located somewhere in our galaxy would measure the radio emission from mobile towers to rise and fall in intensity as different parts of the Earth rotate into view.

The model is complicated by the fact that the transmission of mobile towers is typically beamed towards the horizon. This means that at any given time, towers that are viewed to be setting or rising on the Earth’s horizon will contribute most to the measured signal.

An advanced civilization making many precise measurements of this radio leakage over time could probably conclude that our planet is mostly covered by water and is separated into several major land masses. The radio leakage typically come from the land masses rather than the water.

They might also be able to tell that while most of the mobile radio leakage is associated with lager towns and cities, it is not completely confined to them. This reinforces the idea that we are a nascent technical civilization that is making its way out into the surroundings.