We have been sending signals to the cosmos for almost a century through high-power radio transmissions or even with military radars that exist around the entire planet. Little by little, humanity has been creating an electromagnetic “bubble” that expands at the speed of light, but unfortunately for some, we have not yet received a response to all these signals, and it is easy to fall into pessimism about the absence of other living beings beyond our atmosphere.
The mathematics. The question here is not if we will connect with extraterrestrial intelligence, but when. And here the scientific community has great optimismsince the astronomical community is not based on UFO sightings, but on pure statistics. Here institutions like SETI They have been scanning the sky for decadesand although there is still no evidence of interference or signals of artificial origin, the conviction that we are not alone is stronger than ever.
The bubble. To understand why scientists are so sure of this, you first have to look at the scale of the problem in our Milky Way, which is 100,000 light years across. This monstrous figure collides with our radio bubble that barely touches 100 light years, so on a galactic scale, we have not even crossed the street.
This is where the famous Fermi paradox comes into play, which suggests that, if the universe is so vast and old, there should be someone around us, and that is why the question this researcher asked went down in history: where is everyone? The answer most supported by modern astrobiology is based on the “Mediocrity Principle”, an astronomical concept that maintains that there is nothing special about Earth and suggests that, if life arose here under certain physical and chemical conditions, it is statistically inevitable that it has arisen on a fraction of the billions of exoplanets that orbit habitable zones in our galaxy.
Investigation continues. In 2016, an influential study from Cornell University put numbers to this paradox. To do this, the Drake equation was crossed with the expansion of our radio bubble with the aim of calculating how far our signal would have to travel to reach a sufficient number of stars to guarantee, by pure statistical probability, an answer.
The result yielded a figure that has become a recurring reference in spatial dissemination: contact should not be expected before about 1,500 years. According to this mathematical model, for our signals to reach extraterrestrial ears requires that we cover at least half of the galaxy. Until then, it will seem like we are alone, even though the universe teems with life.
Where do we look? While the 1,500-year clock continues to tick, scientists are not standing idly by, and that is why we have initiatives like SETI that they are not just looking to hear somethingbut to understand how we should listen to it. And for decades, the search for life has focused on very specific radio frequencies, highlighting the famous 1420 MHz hydrogen emission line, assuming that any advanced civilization would use that universal frequency to communicate. But… What if it’s not like that?
New approaches aim to diversify the search towards broader technosignatures, since it is no longer just a matter of searching for an intentional “hello” in the form of a radio wave, but rather detecting electromagnetic pollution from other civilizations, the use of optical lasers for interplanetary communication, or even searching for signals at low-frequency radio frequencies that until now had been ignored or discarded by terrestrial interference.
Images | Graham Holtshausen
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