Will we discover extraterrestrial technology 40 light years from Earth?
An imaginary journey to one of the exoplanets of the Trappist-1 System © Nasa
The idea is both original and serious. If the Trappist-1 exoplanet system is inhabited by extraterrestrial life with advanced technology, then these aliens certainly take advantage of the short distance between their different planets, which is only 1/10th of that between Earth and Mars. It is therefore reasonable to think that they have developed their spatial domain and communicate between their worlds. Now these electromagnetic signals could reach us under certain conditions.
The discovery of the system Trappist-1 was the biggest announcement of 2017 in exoplanetology. Seven rocky exoplanets found simultaneously and “only” 40 light years away from us. Of course, that still represents some 373,000,000,000,000 km, but on a galactic scale, it is in the same department as our solar system!
Representation of our galaxy. In the red circle, the position of our solar system and most of the stars visible to the naked eye at night. This circle also contains the Trappist-1 system discussed here. Its exoplanets are therefore very close to us. © Waitbutwhy.com
Among the seven exoplanets of Trappist, there is even one of the most Earth-like planets known, with a Earth Similarity Index 84%: this is Trappist 1e, which has approximately the same diameter and gravity as the blue planet.
Artist's illustration of the Trappist system and comparison with the Solar System. © Nasa / Caltech
Knowing that we discovered these exoplanets by the so-called transit methodthey can align with us, thus allowing them to capture possible interplanetary communication signals, as shown in the diagram of this study published on September 12, 2024 on the ArXiv platform.
During a “planet-planet” alignment, signals sent from planet “b” to planet “c” could reach us. © Nick Tusay & al, ArXiv
The Arrey radio telescope network was therefore used, first to test the principle with the planet Mars and one of its orbiters with completely human technology, then in the direction of the Trappist exoplanets.
Results of the listening campaign
11,127 “narrowband” signals were captured, of which 1,627 were ultimately similar to the planet-planet model. But after eliminating the various candidates, no extraterrestrial technology was found, although several signals had certain characteristics. One of the discriminating parameters is that they did not repeat themselves, for example.
Example of a PPO candidate signal, ultimately excluded due to its non-repetition. © Nick Tusay & al, ArXiv
So, no planet-planet electromagnetic communication as modeled from Trappist-1.
This research can indeed make you smile. There are renowned astronomers who have spent thousands of hours observing the depths of the cosmos to estimate in fine that so-called intelligent life has only developed — accidentally — among us. Others, a large number, think on the contrary that faced with the immensity of the Universe and the astronomical number of exoplanets, the probability that life has appeared only on Earth is negligible. In any case, if we know what we are looking for, we never know what we will find. This is why this kind of scientific studies and reflections are beneficial to Humanity.
And as Arthur C. Clarke, scientist and novelist, mischievously summed it up: “There are only two possibilities: we are alone in the Universe or we are not. Both possibilities are equally terrifying.”
