Blog #29 - Alien Megastructure

Alien Megastructure 

In 2015, a team of Yale researchers led by astronomer Tabetha Boyajian found an incredibly strange transit event occurring on the star KIC 8462852, or "Tabby's Star". Observed by the Kepler Space Telescope, KIC 8462852 showed multiple massive dips of the incoming stellar flux. Typically these types of drops signify a transiting planet but in this case the light curve peaks showed incredibly large drops of almost 20% of the incoming light. For reference, when Jupiter transits the Sun, the light curve drops only around 1% of the total flux.

Further contributing to the strangeness of the star was the dimming over time. After hearing of "Tabby's Star", researchers at Cal Tech went back to old observations of the star and found that from 2009-2013, the star displayed a drop of nearly 3% in the short time span. Of the 200 nearby comparison stars they observed, not a single one displayed such drastic results. 

These massive drops were initially contributed to a group of passive comets or planetary building blocks but as the drops showed repetitive transits, these theories were dispelled. Soon, astronomers from around the world were attempting to solve the mystery of KIC 8462852. The Search for Extraterrestrial Intelligence (SETI) is a group attempting to find life beyond our planet and currently leads research on KIC 8462852 in hopes of finding what is causing the strange light curves.

Currently the most exciting theory surrounding Tabby's Star is that of the alien megastructure. Though mostly speculation, SETI and other alien optimists believe that a large intelligently made structure surrounds the star, rotating to collect the energy from the stellar structure. They believe that the "megastructure" blocks the outgoing light of the star for large portions of the orbit, causing the severe drops in the incoming light. 

Unfortunately further research into the megastructure has come up empty. Both radio and infrared telescopes were pointed at the structure in hopes of receiving outgoing signals or "waste heat" if the structure was in fact absorbing heat from the central star. Neither was found and astronomers more or less gave up on the idea that there was a circumstellar structure around Tabby's Star. 

Still the hunt continues to try and identify what was happening in 2015 at Yale. Most astronomers now agree that the curves were probably distorted by some phenomena of the interstellar medium, though no evidence has proven this hypothesis either.