The star that sends incomprehensible signals – Sciences et Avenir

Mégastructure extraterrestre hypothétique

This article is taken from the monthly Sciences et Avenir – La Recherche n°907, September 2022. It is the most mysterious star in the galaxy: located 1480 light-years from the Solar System, Tabby’s star (KIC 8462852) is suspected by some astronomers to be surrounded by a “Dyson Sphere”: a gigantic energy-harvesting megastructure built by an alien civilization. Far from being verified, this hypothesis would, however, allow us to explain the apparently incomprehensible signals it sends us. Signals captured for the first time by the Kepler space telescope. Launched in 2009, this NASA instrument observed the light variations of 150,000 stars in the Cygnus constellation for four years, allowing it to detect the presence of more than 2,000 exoplanets. These were identified using the so-called transit method: the periodic diminution of a star’s brightness is associated with the passage of a planet in front of it. The effect of a transit of a planet on a star’s luminosity is actually very weak: the passage of a body like Jupiter in front of a Sun-like star causes the apparent luminosity to drop by about a 1%, and during a Twin Earth only 0.001%. Flow reduction of up to 22%! To sift through the enormous volume of data collected by Kepler, the researchers first asked volunteer planet hunters by applying to the online citizen science group Planet Hunters. It was these amateur astronomers who were first struck by the surprising light curves of KIC 8462852, a star slightly more massive and bright than the Sun. In fact, these charts showed flow drops of up to 22%! Which ultragiant planet could outshine a fifth of the brightness of a star? “Planet Hunters volunteers then contacted the scientific team to find out what could be the cause of these strange observations,” recalls Tabetha Boyajian, an astrophysicist at Louisiana State University (USA), who has taken the lead research on this star since it was called “Tabby’s Star”. This stellar object is even more intriguing because its dips in brightness are not periodic and can last anywhere from 5 to 80 days, before returning to normal. Therefore, it is impossible to explain them by the passage of a planet. In 2016, Louisiana State University astronomer Bradley Schaefer revealed that by studying archival data, including old photographic plates, he was able to show that KIC 8462852’s brightness had already decreased by 14% between 1890 and 1989. A few months then a study published by American astrophysicists Joshua Simon of the Carnegie Institute in Washington and Benjamin Montet of Caltech in Pasadena further complicates the matter. It shows that during Kepler’s four years of observation of the region, the star’s brightness gradually weakened, with a 1% drop in its luminosity in the first three years and 2% thereafter in six months, before stabilizing over the last. six months of observation. To explain this, the two researchers hypothesize that a collision between two planets orbiting the star could have caused the sudden 2% drop in brightness. Or the explosion of a comet in Kepler’s line of sight. But infrared analysis of the star and its environment by Tabetha Boyajian’s team then ruled out these hypotheses, as well as those of the presence of dust clusters or planets forming around it. The only natural explanation that has not yet been ruled out is the possible presence of a swarm of large comets or planetary debris that would block the star’s light as it passed in front of it. The hypothesis of an extraterrestrial infrastructure still makes the most daring dream In 2021, the research undergoes a new twist: new data published by researchers from the University of Arizona (United States) show that Tabby is gravitationally bound to a small star companion, a red star. dwarf 132 billion kilometers away. But nothing proves yet that this distant body is the origin of the described oddities. “To date, there is still no widely accepted theory about what is behind the strange behavior of this star,” concludes Tabetha Boyajian. So the hypothesis of an extraterrestrial infrastructure always makes the dream more daring. Described in a scientific paper in 1960 by American physicist Freeman Dyson, the artificial sphere would surround a star to capture its energy more efficiently. Thus, a Dyson sphere built around the Sun would receive nine times more energy than is intercepted from Earth. This device would serve a Type II civilization on the Kardachev scale. Proposed in 1964 by the Soviet astronomer Nikolai Kardachev, the latter predicts that a type I civilization is sufficient with the energy available on its planet (4 x 1016 watts), while the type II would need to directly consume energy of his star (4 x 1026 W). A paper published in 2020 by American astronomer Robert Gray classifies our Earth civilization as type 0.72 as of 2015. The inhabitants of the Tabby star system, if they existed, therefore belonged to a much more advanced civilization than ours. While no program dedicated to searching for hypothetical extraterrestrial signals has yet yielded results, it is clear that an increasing number of unidentified flying objects have been reported since the early 2000s, Scott Bray said in May , deputy director of US Navy intelligence, before the US Congress. He carefully specified that nothing could suggest a non-terrestrial origin of these phenomena, without excluding him… So far, military pilots have observed dozens of unexplained phenomena. Drones, birds, new military equipment tested by the Russian or Chinese military? Whatever they are, they represent to US military leaders “a potential threat to national security and air traffic.” Therefore, the US Department of Defense has launched a new program to identify unexplained phenomena and identify experimental “weapons” potentially deployed by warring powers. Fragment of a video taken in 2004 by a US fighter jet, showing an unidentified flying object (black dot). Credit: US DEPARTMENT OF DEFENSE NASA Launches Large-Scale Study The US military was joined on this site soon after by NASA. The goal: to launch robust research in the field, because “the scientific process is valid for dealing with all problems, including this one,” said Thomas Zurbuchen, NASA’s associate administrator. This large-scale study will be led from the beginning of the school year and for nine months by the astrophysicist David Spergel, a specialist in the cosmic background at the University of Princeton (United States). It will be about collecting as much data and evidence as possible and developing scientific tools to analyze them and thus determine their nature and origin, extraterrestrial or not. Hoping that the unexplained signs won’t stay like this forever. First detection of “little green men” In 1967, the Irish Jocelyn Bell was a student in Cambridge (United Kingdom). He is working on the realization of a radio telescope intended to study the scintillation of quasars, the brightest sources in the Universe. Examining the instrument data, it detects a signal that repeats with the regularity of the metronome every 1.3 seconds! A message from aliens, the team immediately thinks. Who bats the signal with the name Litte Green Men 1 (LGM or Little Green Men 1). Returning to her work, Jocelyn Bell detected a new, similar source at a distance from the first. Could this be a new class of celestial objects? Since then, astronomers have shown that green men are rapidly spinning neutron stars, called pulsars. Today, all these rotating stars are listed under the acronym LGM: Little Green Men!
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