A new study suggests that the mysterious dimming effect noted occurring periodically from the star KIC 8462852, a phenomenon some have hypothesized might be caused by an artifact of alien construct (or “alien megastructure”), could possibly be the result of something quite natural, though rather enormous in scope. Instead of the fantastical concept of a structure built by aliens, the study concluded the dimming might be produced by a swarm of comets. And yet, researchers did not rule out that the
Space.com reported November 30 that KIC 8462852, a Kepler telescope discovery that showed considerably dimming (up to 22 percent) in 2011 and 2013, may at times be occluded by the periodic passing of an orbiting group of cometary material. Using NASA’s Spitzer Space Telescope, which has the capability of infrared detection, a team of astronomers led by Iowa State University’s Massimo Marengo studied the anomalous star in January.
Going in, the astronomers were armed with various hypotheses concerning KIC 8462852, which is located approximately 1,500 light years away. Besides the “alien megastructure” position (which entailed that an alien civilization constructed something like a Dyson Sphere around the star), other popular offerings included a massive asteroid collision and a cloud of broken-apart comets.
With the Spitzer Space Telescope, scientists were able to determine whether or not the occlusion might be caused by planetesimals in orbit around the star. Dust and rocky objects emit infrared light once heated, and it was that signature for which Marengo and company searched.
Succinctly put: They didn’t find any such wavelength emissions. Marengo and his research team wrote in the study, “The lack of strong infrared excess 2 years after the events responsible for the unusual light curve observed by Kepler further disfavors the scenarios involving a catastrophic collision in a KIC 8462852 asteroid belt, a giant impact disrupting a planet in the system or a population of dust-enshrouded planetesimals.”
The astronomers instead believe that the dimming of the faraway star could be caused by a grouping of comets or comet fragments that circle KIC 8462852 in a long elliptical orbit. Their passage in 2011 — with a trailing end in 2013, as noted by Kepler — could explain the occlusion effect and also why Spitzer did not detect the phenomenon in its search — as the comet material would have by then moved off into deep space. The findings of the study were published in The Astrophysical Journal Letters.
KIC 8462852 has been a topic of speculation since its discovery was announced in September. Located in the constellation Cygnus, it is a main sequence star detected by the exoplanet-hunting Kepler telescope. But it was the strange dimming of the star that attracted attention. So, along with several hypotheses of a natural cosmological cause, the position that it could be the work of aliens also was presented.
The SETI (Search for ExtraTerrestrial Intelligence) Institute reported in early November, according to NBC News, that after two weeks of training the Allen Telescope Array (42 twenty-foot-wide telescopes) on the star, no broadcast emissions were detected. The Institute concluded that although nothing was detected, that did not rule out the possibility of aliens, but strange phenomena historically are found to be products of nature.
The Marengo study, it should be noted, did not rule out the possibility of alien involvement in the dimming, either. In a statement posted through the Iowa State University News Service, he admitted that the astronomer team did not look for artificiality in their data search. “We can’t really say it is, or is not,” he said. “But what the star is doing is very strange. It’s interesting when you have phenomena like that — typically it means there’s some new physical explanation or a new concept to be discovered.”