'Alien Megastructure Star' Continues To Be A Mystery

The "alien megastructure star" anomaly is still as mysterious as ever. The dimming star also known as Tabby's Star had many theories trying to explain the strange phenomenon.

The unusual light fluctuation was discovered by an online astronomy crowdsourcing site called Planet Hunter. NASA's Kepler Telescope documented KIC 8462852's anomaly after monitoring it between the years 2009 and 2013.

After NASA's Kepler team vetted the unusual patter, the Search for Extraterrestrial Intelligence Institute (SETI) also started to monitor Tabby's star.

SETI's senior astronomer Seth Shostak declared for CNN in November that the institute was not able to pick up any radio signals from the star system. However, this does not totally rule out the possibility of intelligent life in KIC 8462852.

Astronomers came with various hypothesis about the star system KIC 8462852, ranging from an "alien megastructure" to comets. A report published on the website Arxiv.org presents a new analysis of the star. The study shows that the star system located around 1,500 light years away from Earth has been dimming gradually for over a century. The phenomenon is not likely to be produced by orbiting comets.

An astronomy and physics professor at Louisiana State University, Bradley Schaefer, examined data from an archive of digitally scanned photographic plates from Harvard University archive. The plates date back more than a century. The professor noticed that the star system was also dimming between the years 1890 and 1989.

Schaefer told CNN that this phenomenon is inexplicable and unique. The star is a sequence star of F-type that usually does not dim by 20 percent as Tabby's Start did. The professor added that millions of other stars of this particular type have been monitored but they did not show a dimming light over time.

The theory that the fading light is caused by comets is wrong, according to Schaefer, because the trend of century-long dimming would require around 648,000 giant comets to pass in front of the star.