KIC 8462852 Update as of 8/7/16

By John Michael Godier

This is a continuation of my coverage of the KIC 8462852 potential alien megastructure star story. For a more detailed look at the back story, check out my video of April 10th of this year for an in-depth report, link in the description below. For those looking for new information on what's been happening over the summer, let me start by saying that the plot has most definitely thickened.

For starters, while still unlikely, the alien megastructure theory has still not been discounted and no satisfying natural explanation has yet emerged. What has happened is new observations have been released that paint this star in an even stranger light than was the case just a few months ago.

At the beginning of the year, Dr. Bradley Schaefer determined from photographic plates at Harvard that KIC 8462852 had dimmed overall over the course of a century in addition to the bizarre periodic deep dips in brightness that were seen by Kepler. This fell into question when another group of scientists published a paper calling Schaefer's methodology into question and suggesting that there was no overall dimming trend which was then widely reported in the media. Unfortunately, the methodology of the people questioning Schaefer's methodology has also been called into question, and the whole thing is now somewhat of a mess.

But that brings us to the new findings which may render the whole argument moot.

A few days ago a paper was published by Benjamin Montet and Joshua Simon that details a study they conducted using the Kepler data and found some astonishing results. Potentially backing up Schaefer's findings, they found that KIC 8462852 did in fact exhibit an overall dimming trend over the time that Kepler observed it. But not only did it dim, it also changed the rate at which it dimmed. For about the first thousand days of the observation period, the star dimmed at a fairly constant rate for a cumulative total of about .9 percent. Then for the last 200 days the rate abruptly increased, and the star dimmed overall a further two percent. That's a lot of overall dimming in a very, very short amount of time.

One possibility mentioned in the paper is that a forming polar spot on the surface of the star could be responsible for the long term dimming. This has not been observed with this class of star before, but has been seen in stars of other classes. However, this would not account for the periodic large-scale dips in the star's brightness that caught everyone's attention in the first place. For this to be the reason behind the long-term dimming, it would have to be a completely separate phenomenon from whatever is causing the periodic deep dips. It seems hard to swallow that two completely different but equally strange phenomena would be happening to the same star.

The good news is that KIC 8462852 will get the study it deserves and the mystery will eventually be solved. Earlier this year, Dr. Tabitha Boyajian and her colleagues ran a successful kickstarter blitz to raise money to buy telescope time in order to study the star for a year. They were successful. In addition to that, multiple telescopes both amateur and professional are being pointed at the star ever since it emerged from behind the sun a few months ago. It will be interesting to see what they find, but what will be even more interesting when they get spectrum data on one of the periodic deep dimming events. That will tell us much and most importantly it will tell us if the star is being blocked by solid objects, or if it's being blocked by a more diffuse conglomeration of material. If it's a transparent cloud, then that would probably point to a natural explanation and go far in ruling out alien megastructures as a cause. If they turn out to be solid, then this story will get even more interesting very quickly. Be sure to stay tuned.

So there you have it, while the alien megastructure hypothesis remains standing, it will most likely be discounted and a natural explanation will eventually be found with more thorough study of the star. And even if it turns out not to be alien life, this will still be one of the most interesting and mysterious stellar objects we've ever found. Whatever this is, it's something we definitely haven't seen before. But I stress, alien megastructures remain highly unlikely as an explanation, it's merely one possibility. That said, it's always fun to speculate, and being a science fiction author I simply can't resist.

One of the most frequently asked questions regarding this story is why aliens would go through the trouble of creating such enormous structures in the first place. I wonder this myself, as I suspect that advanced alien species would probably not be detectable at all, see my video on nanotechnology for a discussion on that very subject, link in the description below. But there are several speculative answers to this question that I'd like to present.

The first reason would be power generation. This is the most basic assumption in the Dyson sphere concept, you build solar collecting arrays to harvest energy from your star. Eventually, if the engineering proved to be possible at all, there is some debate there, you could envelope your star entirely with a shell and harness 100% of its energy.

But that's not the only reason to build a megastructure. There are several others but the one I find most intriguing specific to Tabby's star is the concept of a stellar engine designed to physically move a star. The reason this is so interesting is because one aspect of this star that hasn't received much attention is that it has a companion star that we don't really know that much about.

Not far away there is a small red dwarf either orbiting it as a binary star system or the stars are separate systems passing by each other. In fact, the apparently discounted cold comet explanation relied on this star passing by and disrupting Tabby's Star's Oort cloud sending the comets careening towards it. But if you were a civilization that had a star passing dangerously close to your system, one way to avoid getting bombarded by comets would be to simply move your star. Are the aliens running from the red dwarf or are they native to it and pushing Tabby's star out of the way? I can't say, but I can say that neither is likely because it's still overwhelmingly probable that we're observing a natural phenomenon that we don't yet understand. It's just a very weird one.