Are we alone in this universe? A question that fascinates both scientists and the public. In science, the focus is on our search for life elsewhere. However, the notion that we are being watched by a distant alien civilization is usually confined to the world of science fiction.
But if there are other technological civilizations, they are probably much more advanced than ours. After all, in the last 200 years we have evolved into a new technological (industrial) civilization: any other technological civilization could easily be 1,000 or 10,000 or even 100,000 years ahead of us.
And no one can deny that the pace of our technological progress is accelerating, in some cases at an alarming rate. Science fiction author Arthur C. To quote Clarke's third law, it seems to us that an advanced civilization, given its technological capabilities, is capable of magic.
In recent years, my colleagues and I have begun to question whether advanced civilizations can detect technological signatures such as radio emissions from Earth. And if so, what can you see?
Our latest research gives a clue.
This is not the first study of this kind. However, it has now been more than 50 years since the topic was not sufficiently considered. Although much has changed since the mid-1970s, the biggest change in the last two decades has come with the introduction of the mobile phone. These devices and their connecting towers created a new technological signature for broadband radio broadcasting.
Although 4G cell phones and cell towers are relatively low power (0.1-200 watts), there are many of them: billions of cell phones and millions of towers. And the radio emission accumulated by her begins to become very important. But is an alien civilization watching from afar? We want to find out.
It's quite difficult to find a public database listing the locations and transmission characteristics of all cell towers in the world. But using the OpenCellID database and along with crowdsourced population data, we can create a simple model that estimates the distribution of cell phone towers around the world.
Our model is certainly crude and imperfect, but it's our best estimate of the number of engineered cell towers going into space.
As the Earth spins on its own axis, advanced civilizations somewhere in our galaxy are measuring radio emissions from towers that move up and down as they rotate between views of different parts of the Earth.
This model is complicated by the fact that cell tower transmissions are usually aimed at the horizon. This means that at any point in time, the visible tower that is above or above the Earth's horizon is the largest contributor to the signal measurement.
An advanced civilization that has made many precise measurements of these radio emissions over time could conclude that our planet is mostly covered by water and divided into several large landmasses. Radium leaks generally come from land, not water.
They may also find that while most cell phone losses are land-based, cell towers (and possibly their smart users) are on the coast.
You'll also notice that a network of cell towers is evenly distributed across the planet. This differs from the traditional radio leak previously recognized as a sign of key technologies, particularly TV stations and radar.
Our simulations show that developing regions such as Africa and Asia contribute significantly to Earth's current scattered radiation. This is not surprising given the importance of cellular systems in all aspects of society in developing countries.
We calculate the energy emitted by the earth, which is a maximum of about 4 gigawatts (GW) (one gigawatt can power about 750,000 homes for one hour). We estimate the observed transmission from three different stars in our galaxy: HD 95735, Barnard's Star, and Alpha Centauri A.
We found that an extraterrestrial civilization near this location would need a much better telescope than ours to detect earth-moving radio scatter. However, it is very likely that most technological civilizations consider themselves much more advanced than ours.
You can also watch other types of broadcasts, such as military radar systems and space communications transmissions from distant spacecraft, such as the Voyager spacecraft. Although these signals would be relatively rare for extraterrestrials to observe, they have the advantage of being very strong.
Wireless technology signatures are perhaps the defining feature of our civilization's existence, at least from an outsider's perspective. But even alien species would experience scattered radiation (including visible light) across the electromagnetic spectrum.
If we continue to increase our energy use at the current rate, "waste heat," the inevitable end product of energy use, will also be thrown into space. There it will manifest as an unusual excess of infrared wavelengths, a sign of an active technological civilization.
Other technological signatures, including industrial pollutants in Earth's atmosphere, would also be visible to extraterrestrials equipped with powerful telescopes and spectral analysis systems (which separate light based on wavelength). Undoubtedly, advanced extraterrestrial civilizations have a good understanding of our particular stage of industrialization and energy consumption.
On Earth we use the Kardashev scale to estimate the development of an extraterrestrial civilization based on its energy consumption: on this scale we would look like an emerging technological civilization that has not yet reached the bottom of the ladder.
And even if the alien species can't detect any of this now, things will soon get better. We plan to extend this work to traditional radio technology companies and other emerging sources of radio leakage, including 5G systems, WiFi, digital transmission, and space communications.
It also contains the cocoons of radio emission that will soon surround Earth as giant satellite constellations like Starlink and OneWeb bring global Wi-Fi coverage.
Who knows, aliens might even be able to decipher the complex modulations of our cellular communication systems. Eventually, since Earth will be artificially illuminated in all wavelengths, it cannot be ruled out that they will be discovered before we discover them.
This article has been republished by The Conversation under a Creative Commons license . Read the original article .
Photo credit: Crescent seen from the moon / NASA
Post a Comment