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Where are all the extraterrestrials? For decades, humans have been searching for artificial signals, but the sky above is silent. But new research suggests that researchers' research has so far not been particularly exhaustive; if the total possible search space was equivalent to the total water of the Earth's oceans, we only examined the volume of a hot tub.
In many movies, the galaxy is teeming with intelligent life forms that crisscross spaceships and produce other obvious signs of their existence. In reality, programs such as the Search for Extraterrestrial Intelligence (SETI) have not encountered any noticeable transmission of another species. This lack of contact was first dubbed "the great silence" by science fiction author and physicist David Brin in a classic 1983 article in the Quarterly Journal of the Royal Astronomical Society. [9 Strange, Scientific Excuses for Why We Haven’t Found Aliens Yet]
"It is often said that we have been searching for about 40 years, but we have always found no sign of extraterrestrial civilization," said Shubham Kanodia, postgraduate astronomy student at Penn State University and co-author of the new article. in the pre-print newspaper arXiv, which was submitted to The Astronomical Journal. "We wanted to see how much we had watched and how much more we needed."
Researchers consider radio telescopes to be an obvious instrument for such investigations, as radio waves move easily through interstellar dust and, in some parts of the radio spectrum, background interference is minimized. "It's the" silent cosmic zone "where we can best listen for a slight murmur across the interstellar expanse," as an article on the website says. 39, SETI Institute.
But what part of the sky did researchers look for such radio signals? In collaboration with his colleagues, Kanodia has created a rigorous mathematical framework to analyze previous SETI searches. The researchers examined eight distinct parameters, including the amount of sky detected by a telescope, the sensitivity of the observatory to the search and the power of a potential signal. They concluded that, over the entire possible search space in which a signal could have been hiding, SETI's previous searches had examined about 5.8 times 10 out of 18 points, or about one-fifteenth of the time. 39 space available, which in itself is only a tiny part of the vast range of potential bandwidth that scientists could explore.
The results support those who argue that "the great silence" is only one artifact of our limited investigations. "Bright and obvious radio beacons could be quite common in the sky, but we would not know it yet, because our search is so complete so far," wrote the authors.
According to Kanodia, there is much more room to extend these exams, as SETI research now goes beyond radio wavelengths. New studies are also targeting signals in optical tapes, as intelligent aliens could send powerful optical laser pulses into the universe, as signals or as a method of piloting interstellar vessels equipped with solar sails, said Kanodia. Together with his colleagues, he hopes to be able to quantify the amount of optical SETI that has been achieved so far, he said.
However, even if we were carefully looking for optical and radio wavelengths, this would probably only be a small part of the potential search space. In the course of their history, aliens may have encountered many phenomena that humans have not known, some of which may be useful for generating signals, Kanodia said. "In all probability, there is still a lot of physics that we have not yet deciphered or understood," he said. "If you tried to communicate with a caveman with a walkie-talkie, you will not get an answer."
The results are encouraging, said Jill Tarter, astronomer and former director of the SETI Research Center, who had already done similar calculations. His findings suggested that total SETI searches were related to the search for a glass of seawater and concluded that there was no fish in it. 39; ocean. "I was glad to see that I was in the right stadium," she said. "It's a very big ocean, and so far we have not been able to investigate a lot."
<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Editor's note: This story was updated to note that the study examined eight parameters, including the amount of sky searched by a telescope and not the number of star systems."data-reactid =" 32 ">Editor's note: This story was updated to note that the study examined eight parameters, including the amount of sky searched by a telescope and not the number of star systems.
<p class = "canvas-atom canvas-text Mb (1.0em) Mb (0) – sm Mt (0.8em) – sm" type = "text" content = "Originally published on Science live."data-reactid =" 33 ">Originally published on Science live.
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