Source: The Space Reporter.
KIC 8462852 has a dimming phenomenon that happens in such an interval that has lead many to speculate off their handles. For a while, an alien superstructure the size of a Death Star was the leading explanation. When SETI listening posts detected no artificial signal, that theory, however remote, was cast aside. So, many believe the likely scenario was a comet that had fragmented into pieces as the likely cause.
No, the comet theory is also out the window. For the type of dimming witnessed, it would require more than 600,000 comets to make that happen.
What next? The reason the alien structure theory was dismissed is because we detected no radio signal. But if an alien civilization thousands or tens or hundreds of thousands of years more advanced than we are can build a structure or structures large enough to cause the dimming of a star by up to 20%, would it not be conceivable that they no longer use radio signals and what ever form of communication they use would be far beyond anything we have or can think up? Subspace, anyone?
One other prevailing theory is that KIC 8462852 has some sort of ring that would cause the kind of dimming we witness here on earth. At this point, the likelihood of an artificial cause is just as plausible as natural ones. We simply do not know with any certainty one way or another.
For now, we just have to keep looking up at the sky and wait until better and more precious instruments come online to give us the answers we are looking for.