Why Have We Never Discovered Aliens? Scientist Offers a New Explanation

In the quest to unravel the mysteries of the universe, one enigma continues to captivate our imagination: the absence of communication with extraterrestrial beings. 

A researcher from the Statistical Biophysics Laboratory at École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland has reached a new explanation for the lack of communication with extraterrestrial beings, "if they exist".

"We've only been looking for 60 years," says biophysicist Claudio Grimaldi. "Earth could simply be in a bubble that just happens to be devoid of radio waves emitted by extraterrestrial life."

In short, there's just too much space to scan, and most likely not enough alien transmissions cross our path. That's based on a statistical model previously used to study porous materials like sponges – only instead of pores within a material, it was deployed to assess the distribution of extraterrestrial signal emitters that may, or may not, be somewhere out there in space.

The message is to be patient. Searching for evidence of communication in the universe requires time, effort, and resources, and there is some debate about whether the search for extraterrestrial intelligence (SETI) is worth our time.

The research model starts with the assumption that there's at least one electromagnetic signal of technological origin in the Milky Way at any given time, and that Earth has been in a quiet bubble (or sponge pore) for at least six decades, if not more.

If that's the case, then statistically there are fewer than 1 to 5 electromagnetic emissions per century anywhere in our galaxy. To put it another way, they're about as common as supernovas in the Milky Way – so not very common at all.

In assessments like this that involve probability, there are often assumptions that can be massaged. It's possible to adjust factors to be a little more optimistic (or pessimistic), adjusting the likelihood of catching a signal in the future.

According to the most optimistic scenario, with the given conditions, Grimaldi says it could take at least 60 years before we receive a signal from extraterrestrials. In the least optimistic scenario, we could be looking at waiting over 2,000 years. In both cases, we would need a directed wireless telescope.

"We may have been unlucky in that we discovered how to use radio telescopes just as we were crossing a portion of space in which electromagnetic signals from other civilizations were absent," says Grimaldi.

"To me, this hypothesis seems less extreme than assuming that we are constantly bombarded by signals from all sides but are, for some reason, unable to detect them."

As our tools for observing space continue to improve, we are discovering more and more planets that may have the suitable conditions for life, which means a greater chance that extraterrestrial life is attempting to make contact.

However, we still have a vast space to cover in our search, and that's why modeling is important in determining where to look.

If an alien civilization were to evolve, for example, it may cluster around a set of planets and not spread evenly as assumed in this analysis.

Grimaldi suggests that the best way forward is inclusive investigations: searching for signals in data collected by telescopes focused on other missions rather than using telescopes specifically designed for space communications.

"The best strategy might be to adopt the SETI community's past approach of using data from other astrophysical studies – detecting radio emissions from other stars or galaxies – to see if they contain any technosignals, and make that the standard practice," says Grimaldi.


Inferring the Rate of Technosignatures from 60 yr of Nondetection;

Published 2023 April 13 • © 2023. Published by the American Astronomical Society.

The Astronomical Journal, Volume 165, Number 5

DOI 10.3847/1538-3881/acc327


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