Sunday, September 5, 2021

Star of 'alien megastructure' blinks again

 Over the weekend, astronomers around the world aimed their telescopes at the star KIC 8462852, hoping to decipher the reasons for the mysterious brightness.
 Astronomers across the planet mobilized this weekend, after detecting that the star KIC 8462852, responsible for emitting a mysterious light, "blinks" again.  
Scientists have aimed their telescopes at the celestial body, located about 1,500 light-years away (each light year equals 9.46 trillion kilometers) from Earth, between the constellations of Swan and Lyra, hoping to, by first time, track the star's activity in “real time” (or as close to it, due to the star's distance from our planet).  With that, they aim to obtain new evidence that will help decipher the unusual patterns of its brightness.

 KIC 8462852, discovered in 2011, displays such a bizarre light that, in 2015, scientists came to the conclusion that the most plausible scientific explanation for its behavior would be an incredible megastructure built by aliens.  The hypothesis – taken seriously by astronomers – was raised by researchers led by Tabetha Boyajian, of Yale University, in the United States, and astronomer Jason Wright, of Penn State University.  Because Tabetha is in charge of the studies, the star is also called “Tabby's Star”, or Tabby's Star, in Portuguese translation.
 Months later, NASA scientists claimed that a "swarm" of comets could be behind the star's unusual patterns of brightness: a family of them would be traveling in long, rather eccentric orbits around them, causing eerie luminosity.  The idea of ​​the structure built by extraterrestrials, however, was not discarded.
 The biggest enigma of the Star of Tabby, according to astronomers, is the great decrease in its brightness, between 15% and 25% - the most common is that this number is between 1% and 2%.
 In September 2015, an article in the periodical Monthly Notices of the Royal Astronomical Society described KIC 8462852, a star observed by the Kepler telescope, the most competent planet hunter outside the Solar System, launched in 2009. The powerful instrument's lens catches the glare of the stars – when there is a patterned decrease in the light emitted by them, it means that something is passing between the star and the telescope.  Most of the time, it is a planet (which is usually intermediate in size between Earth and Neptune).  However, KIC 8462852 emitted an unprecedented light pattern.  Normally, when a planet passes a star, its brightness decreases between 1% and 2%.  But during the four years of Kepler observations, the light from KIC 8462852 decreased between 15% and 25%, and at random intervals.  It is 1.5 times the size of the Sun, and to darken it that way would require a very large object – much larger than a planet.
 After discarding several explanations, scientists began to hypothesize that the star's bizarre behavior could be the result of an incredible structure built by aliens to capture the star's energy, called the Dyson Sphere (because it was proposed in 1960 by the British physicist Freeman Dyson).  It would be composed of gigantic solar panels that, little by little, would block the glow of the celestial body.  In November of the same year, astronomer Massimo Marengo of Iowa State University in the United States stated that the unusual pattern could be caused by icy comets surrounding the star and causing the mysterious shadow – but the new explanation was not enough to invalidate the megastructure hypothesis.
 At the end of last Friday, the Institute of Astrophysics of the Canary Islands gave the alert of the star's activity – it would be fading again and would have reduced its brightness by 2%.  With the new observations, scientists intend to gather more data about the light from KIC 8462852, which would either support or rule out hypotheses about the explanations for its brightness.

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