One of the continuing story subtexts in all the recent deep space and exoplanet discovery articles, not to mention those covering the accumulating data from planets and moons within our own Solar System, is that the existence of alien life cannot be ruled out. As an exception to this, in further study of Tabby’s Star, the mysterious dimming star KIC 8462852, it was revealed that the cause of the dimming effect was most likely due to a natural phenomenon, and it could be ruled out that the strange effect was caused by an alien megastructure or some artificial construct of alien design.
But is that correct?
To be precise, according to an article posted to Phys.org, one of the lead co-authors of the study, star namesake Louisiana State University’s Tabetha Boyajian, noted that the dimming and brightening of KIC 8462852 was due to a massive cloud of dust and was “not opaque, as would be expected from a planet or alien megastructure.” The conclusion was derived from perusing months of observation data of the so-called “dimming star” — which is over a thousand light years from Earth — that captured four separate dips in the object’s brightness. By studying the various wavelengths, it was determined that the effect, if it were a more solid or opaque obstruction, would present itself in the dimming data as a similarity in wavelength depth.
Penn State’s Jason Wright, also a co-author of the study, supports Boyajian’s conclusion. He writes in his blog, AstroWright, that the new study suggests “we now have no reason to think alien megastructures have anything to do with the dips of Tabby’s Star.”
Although they may be correct, Boyajian and Wright’s conclusion could well be flawed in the thinking that an extraterrestrial civilization so advanced to be able to build an alien megastructure that could surround (or even partially surround) something as large as a star would be constrained to using materials that might not allow some filtering. That is, not getting similar wavelengths or some wavelength uniformity from the dimming star data might not actually rule out an alien megastructure if such a massive construct was built using materials that allowed at least some of the star’s light to pass through.
And then there is the possibility that the dimming is caused by a structure that is itself only partially complete.
To be clear, a Dyson sphere might not have to be opaque or made of some solid, all-light absorbing material, nor does it have to be a finished alien product.
Sure, the dimming of star KIC 8462852 most likely is the result of “something ordinary, at least on a cosmic scale,” as the authors write in their paper that appears in The Astrophysical Journal Letters, but stating that a star-occluding alien megastructure can be ruled out is not accurate. A construct of alien design is simply, according to the accumulating data, less likely to be an actuality.