The mystery surrounding KIC 8462852, an F type main sequence star residing in the constellation Cygnus 1,480 light years from Earth, is just getting curiouser and curiouser. The hitherto obscure star burst into the news last year when astronomers noted strange and non-periodic dips in brightness. One theory that explained this phenomenon pointed to an alien megastructure such as a Dyson sphere. Then, scientists concluded that the dips in brightness was likely the result of comets. Now, according to a Wednesday story in Cosmos Up, the comet theory has been ruled out. Scientists are scratching their heads, looking for another natural explanation, not quite willing to suggest that it’s aliens.
“Within the various dust-occultation ideas, there is some quantity of dust required to create the one deepest dip of 20%: Boyajian and Thompson calculate that the comet family scenario requires 648,000 giant-comets (each with 200 km diameter) to create the century-long fading, all orchestrated to pass in front of the star within the last century — this can be compared to the entire mass of the Kuiper Belt in our own Solar System.”
The idea that any solar system could have 648,000 giant comets and that they would all line up in such a way to explain the dips in brightness is considered unlikely at best. The conclusion is driving scientists back to the drawing board, as the cliché states.
The dips in brightness were calculated by the Kepler Space Telescope, using them to determine whether or not KIC 8462852 has planets or not. The star apparently does not have planets. What it does have is something that scientists are still trying to explain.
Mitigating against the alien megastructure theory is the fact that Extraterrestrial Intelligence Institute, SETTI, trained its Allen Telescope Array on KIC 8462852 and not finding any alien signals. On the other hand, perhaps any aliens who are alleged to have built the megastructure around the star are either dead and gone or use some other communications technology, such as lasers. In any case, whatever is causing the strange dips in brightness is likely to be amazing, not matter whether it is natural or aliens.