More than sixty years ago, the search for alien intelligence (SETI) officially started with Project Ozma on the Greenbank Observatory in West Banker, Virginia. Under the guidance of the famous astronomer Frank Drake (who devised the Drake comparison), this examination of the 25-meter (82-foot) dish of the Observatory to check Epsilon Eridani and Tau Ceti-Twee nearby Son-like star tusses in April and July 1960. Since then, several surveys have been carried out. Universetoday.com.
Although no conclusive evidence has been found that indicates the presence of advanced civilization, there have been many cases in which scientists could not exclude the possibility. In one Recent paperVeteran NASA scientist Richard H. Stanton describes the results of his multi-year survey of more than 1300 sun-like stars for optical SETI signals. As he indicates, this survey revealed two rapid identical pulses of a sun -like star about 100 light years of the earth, which correspond to similar pulses from another star that was observed four years ago.
Dr. Stanton is a veteran of NASA’s Jet Propulsion Laboratory (JPL), whose work includes participating in the Voyager missions and serving as the engineering manager of the Gravity Recovery and Climate Experiment (Grace) Mission. Since his retirement, he has committed himself to the search for alien intelligence (SETI) using the 76.2-cm (30-inch) telescope in the Shay Meadow Observatory in Big Bear, California and a multi-channel photoometer that he has designed. The paper that described the findings of his survey appeared in the Astronautics magazine Astronautics.
For years, Stanton used these instruments to observe more than 1,300 sun-like stars for optical SETI signals. In contrast to traditional SETI surveys that radio antennas have used to look for proof of potential alien transmissions, optical Seti is looking for light pulses that can result from laser communication or arrays with targeted energy. This last example has been taken into consideration in recent years thanks to Project Starshot, NASA’s targeted energy propulsion for interstellar exploration (deep) concept and similar interstellar mission concepts.
As Stanton indicated, the Optical Seti field follows its roots to study from 1961 by Schwartz and Townes. They reasoned that the best way in which an alien intelligence (ETI) could send an optical signal that would surpass their star with intense nanosecond laser pulses.
As Stanton today via e -mail related to the universe, his SETI search divides from conventional optical surveys:
“My approach is to stare at a single star for about 1 hour with the help of photonization to taste the light of the star at what is considered a very high time resolution for astronomy (100 microsecond samples). The resulting time series are then searched for pulses and optical tones. Discovery of similar pulses.”
After years of searching, Stanton reported an unexpected “signal” when observing HD 89389, an F-Type star slightly brighter and more massive than our sun, located in the Constellation Ursa Major. According to Stanton’s article, this signal consisted of two fast, identical pulses 4.4 seconds apart that were not revealed in earlier searches. He then performed comparisons against signals produced by aircraft, satellites, meteors, lightning, atmospheric scintillation, system noise, etc.
As he explained, various things made about the pulses that were detected around HD89389, she unique to everything that was seen before:
A. The star becomes a clearer fainer and then returns to his environmental level, all in around 0.2s. This variation is far too strong to be caused by random noise or atmospheric turbulence. How do you make a star, more than a million kilometers wide, partially disappearing in a tenth of a second? The source of this variation cannot be as far away as the star itself.
B. In all three events, two essentially identical pulses are seen, separated by 1.2 and 4.4 seconds (the third event found in an observation on January 18 this year, was not included in the newspaper). In more than 1500 hours of searching there is never a single pulse that looks like these.
C. The fine structure in the light of the star between the peaks of the first pulse is almost exactly in the second pulse 4.4s later. Nobody knows how this behavior should be explained.
D. Nothing was detected near the star in simultaneous photography or in the background sensor that easily detects distant satellites that move close to a goalkeeper. Common signals from aircraft, satellites, meteors, birds, etc. are completely different from these pulses.
A re-examination of historical data for similar signals revealed another few pulses detected around HD 217014 (51 Pegasi) in 2021. This G-type G-type G-Type is approximately 50.6 light years of the earth and is comparable in size, mass and age as our sun. In 1995, astronomers from the Observatoire de Haute Provence detected an exoplanet around this star, a hot gas giant that has since been called Dimidium. This was one of the first exoplanets ever detected, and the first time an exoplanet was discovered around a main series.
At that time, Stanton said, the signal was rejected as a false positive caused by birds. However, a detailed analysis has excluded this possibility for all observed pulses. Other possibilities that Stanton explores are Difraction caused by the atmosphere of the earth, possibly due to a shock wave. However, this is unlikely, because shock waves should have had to take place with perfect timing to coincide with both optical pulses. Other possibilities include star lighting fraction due to a distant body in the solar system, partial eclipses caused by earth satellites or distant asteroids, and “edge difraction” by a straight edge (as described by the zomme effect).
There is also the possibility that a gravitational wave could have generated these pulses, which requires extra consideration. Another interesting possibility is that this could be the result of ETI. As Stanton indicated, everything that the light of these stars has modulated, must be relatively close to the earth, which implies that every ETI activity must be within our solar system. However, Stanton emphasizes that more data is needed.
“None of these statements is really satisfactory at the moment,” he said. “We do not know what kind of object these pulses could produce or how far it is. We do not know whether the two-pulse signal is produced by something that goes between us and the star or whether it is generated by something that modulates the light of the star without going over the field. Until we learn more, we can not even say whether or not you are involved!”
There are various examples of optical SETI (OSETI) or laser seti, including the cooperation effort launched by Breakthrough Listen and the very energetic radiation image formation Telescope Array System (Veritas) Collaboration. However, Stanton’s method offers many possibilities for future Seti surveys that can search for similar examples of optical pulses. To this end, he proposes two approaches that can reveal more about this phenomenon and help astronomers to set stricter restrictions on their possible causes:
“Looking for events with Arrays from synchronized optical telescopes. If the object moves between the star and us, this approach must tell us how quickly it normally moves to the line of sight and possibly its size and distance. [Also,] It would be very interesting if the light of the star was modulated without moving an object across the field. Observing events with telescopes separated by a few hundred kilometers can show that every separation in the time that each pulse arrives is only due to differences in the light time of the star until every telescope. Then, unless the variation could in one way or another could be attributed to the star itself, we would have even more to explain! “
