In a paper published last November 2022, a scientist in the Swiss Federal Institute of Technology Lausanne quantifies how the Earth has not heard a radio signal from an Extraterrestrial technological civilization over the course of approximately the last sixty years, when the Search for extraterrestrial Intelligence (SETI) began listening for such signals. They also estimate the possible likelihood related to when we may possibly audibly hear a signal and recommend potential methods that may aid in the continued search for a signal from an extraterrestrial technological civilization.
“One intriguing result of this analysis is it bridges the gap between two widely used but opposing views,’ Claudio Grimaldi, a guest researcher in the Laboratory of Statistical Biophysics in the Swiss Federal Institute of technology Lausanne and Sole author of the study, told Universe Today. One argues that technoemissions pervade our galaxy and that we will find them ultimately, persevering in the search, while the other argues that extraterrestrial technological life is so rare that it could be regarded practically nonexistent. “
“Personally, I would prefer the very first choice over the second,” he stated. But if we wish to get a far more full picture, there might be a third, less extreme possibility. That is, because we began searching with no success only about 60 years ago, it is possible the Earth hasn’t been illuminated by technosignals since that time, although some other regions of the universe might have been. To put it another way, it could be that the Earth has been within a silent bubble for at least 60 years.
Grimaldi’s results supply statistics of whenever a radio signal might pass through the Earth, which he calls a “crossing event,” with a 95 % probability the next crossing event won’t occur longer than 100,000 years, 50 % probability associated with a crossing event happening between no less than 60 to 1,800 years, along with 20 % probability of a crossing event happening no earlier than 240 years.
“In the quiet bubble” scenario, the waiting time is at least sixty years is very optimistic, “Grimaldi told Universe Today. In addition, even after this moment, the fact that the earth can be illuminated by technological signals is a necessary, but not adequate condition for their detection, since they might be missed by our telescopes. ” Hence, even in the upbeat 60-year window for any crossing event, the waiting period until detection could be much longer. “
Given the results of the study offer a broad range of probabilities for detecting a technosignature in the future and since the research focuses solely on SETI’s technosignature searches, what actions could be taken in case we were to rethink current search strategies regarding exactly how SETI conducts its searches?
“If it’s correct it could be a number of years, or even hundreds of years, before a technosignal is potentially detectable, then it may be better to focus on commensal SETI investigations, i.e., looking for technosignals from data collected by telescopes performing other observational activities, rather than investing resources and telescope time in active SETI searches,” Dr. Grimaldi recently told Universe Today.
For now, the famous Wow! is probably the closest we’ve come to detecting a technosignature from an extraterrestrial technological civilization. The signal was a very noisy, but very fast radio signal that was spotted in 1977 by the big Ear radio telescope at Ohio State University. Until we find something similar, or maybe better, we go on to listen to the heavens with patient ears, wishing someone else is out there waiting to be heard.
“we are not alone in the feeling that other life forms could fill up the Universe, not always advanced,” Grimaldi told Universe Today. “Complex or even technological life may be much rarer than what was thought decades ago, but its existence will not be prescriptive.”