And if being in a bubble prevents us from hearing extraterrestrial signals

28 Apr. (EUROPE PRESS) –

Sixty years of unsuccessful searching for intelligent signals in the cosmos make one wonder if the Earth could simply be in a bubble devoid of radio waves emitted by non-terrestrial life.

A recent statistical analysis of this silence in the cosmos suggests this simple and optimistic explanation for the search for other planetary civilizations and urges the SETI community to continue to search, but be patient, since the chances of detecting signals in the next sixty years are slim.

The prevailing explanations for the absence of electromagnetic signals from extraterrestrial societies fall into two extreme categories, he says it’s a statement Claudio Grimaldi from the EPFL Statistical Biophysics Laboratory. The “optimistic” camp holds that we have been using detectors that are not sensitive enough or fail to detect incoming signals because we have been pointing our radio telescopes in the wrong direction. The “pessimistic” field, on the other hand, interprets silence as an indication of the absence of extraterrestrial life in our galaxy.

According to Grimaldi’s study, published in The Astronomical Journal, there is a third explanation. “We’ve only been looking for 60 years. Earth could just be in a bubble that simply lacks the radio waves being emitted by extraterrestrial life,” she says.

Grimaldi’s study is based on a statistical model initially developed to model porous materials such as sponges, which he sees as an apt analogy for the question at hand: “You can imagine that the solid matter of the sponge represents electromagnetic signals radiating spherically from a planet that harbors extraterrestrial life in space”. In this analogy, the holes in the sponge, its pores, would represent regions where signals are absent.

By reusing mathematical tools to study porous materials and using Bayesian statistics, Grimaldi was able to draw quantitative conclusions from the sixty years of observed silence. His findings are conditioned on the assumptions that there is at least one electromagnetic signal of technological origin in the galaxy at any given time and that Earth has been in a silent bubble, or “pore,” for at least 60 years.

“If it is true that we have been in an empty region for 60 years, our modeling suggests that there are fewer than one to five electromagnetic emissions per century anywhere in our galaxy. This would make them as rare as supernovae in the Milky Way.” Way,” says Grimaldi. In the most optimistic scenario, we would have to wait more than 60 years for one of these signals to reach our planet. In the least optimistic scenario, that number would rise to about 2,000 years. If we detect the signals when they cross our path is another matter. In any case, our radio telescopes would have to be pointed in the right direction to see them.

The search for extraterrestrial intelligence is currently going strong, fueled by the discovery some 20 years ago of the first planets beyond our solar system. Today, researchers surmise that there could be as many as 10 billion Earth-like planets: rocky, the right size, and located at the right distance from the sun to support life. Their large number increases the probability that technological life has developed in one of them.

This has led to new initiatives throughout the SETI community. The privately funded “Breakthrough Listen” project, the largest of its kind, has committed nearly $100 million to spend radio telescope time searching for technosignals from extraterrestrial civilizations. With the initiative ending in two years, Grimaldi says that Now is a good time to think about how to continue the search for extraterrestrial intelligence in the future.

“The dream of the SETI community is to search for signals all the time, all over the sky. Even today’s largest telescopes can only see a small fraction of the sky. Today, there are arrays of telescopes, like the Allen Telescope Array (ATA) in California, which point in different directions and can target specific regions to get more detailed information when needed. The same goes for optical telescopes.”

“But,” says Grimaldi, “the truth is that we don’t know where to look, at what frequencies and wavelengths. We are currently observing other phenomena using our telescopes, so the best strategy might be to adopt the past approach of the SETI community.” to use data from other astrophysical studies, detecting radio emissions from other stars or galaxies, to see if they contain any techno-signals, and make that standard practice.”