Here's a better explanation in a long (but readable) series of posts from an actual astronomer, Jason Wright: <a href="http://sites.psu.edu/astrowright/2016/08/30/what-could-be-going-on-with-boyajians-star-part-i/" rel="nofollow">http://sites.psu.edu/astrowright/2016/08/30/what-could-be-go...</a><p>In this series he details several hypotheses and ranks them.
Blackhole starlifting makes more sense to me than Dyson spheres (see section on star lifting): <a href="https://arxiv.org/abs/1104.4362" rel="nofollow">https://arxiv.org/abs/1104.4362</a><p>> Importantly, researchers have concluded that a thin accretion disk around a rotating black hole is the most efficient power source in the universe , a process up to ~50 times more efficient than nuclear fusion occurring in stars (e.g. Thorne 1974; Narayan and Quataert 2005). If any civilization is to climb the Kardashev scale, it would certainly at some point want to master that energetic source. We call such an endeavor black hole star lifting<p>Instead of a Dyson sphere, you're using a black hole (and apparent mastery of gravity) to leech energy directly from the sun.
As a really crazy thought, is it be possible that networks of Dyson Spheres throughout the universe would explain the lower level of visible matter vs the gravity we observe? That is, Dyson Spheres obfuscating their contained stars as an explanation for dark matter?<p>Similarly, the heat would still escape from them. Could that explain the CMB?<p>(I expect that I'm way off the mark, but if nothing else it could make for an interesting premise for some sci-fi.)
If "By far most of the solar system's mass is in the Sun itself: somewhere between 99.8 and 99.9 percent", then I can't help but wonder if there is enough matter to cover the sun's surface area to create a real Dyson sphere. Where would this matter come from? Is there enough matter in left in the 0.1% (shared by the rest of the solar system) to completely engulf the sun?
So interestingly, hiding you star in a Dyson sphere, turns it into the loudest beacon in the galaxy, for a while.<p>If we wanted to be 'found' by aliens, we should do this to our sun.
If I was building a Dyson sphere I would launch multiple modular solar panels into orbit around the star. This is the cheapest scalable way to do it while I collect resources and send more as my energy needs increase.<p>The problem then is getting that energy out. I'd use lasers from my panels to my planet. That means my solar panel collective in orbit around the star will have to always point to my planet for maximum efficiency so I don't have useless panels since there's no way i'm building a battery at star energy scale on each panel.<p>The dimming you see would then be based on the orbit time of my planet around the star, since the panel half halo will always be pointing at my planet. Essentially geostationary around the star.
So if you make a Dyson sphere, your planet is either inside or outside of it.<p>If it's outside, you might get complaints about the shutting off of the day/night cycle.<p>If it's inside, you get all the sun's light reflected off the inside of the sphere. Kinda blinding.
For anyone who has some spare time, here's an enormous time sink:<p><a href="http://www.orionsarm.com" rel="nofollow">http://www.orionsarm.com</a><p>Don't click on that if you have stuff to do today.
My wager: It's a fleet of mega-spaceships passing across the star, probably much closer to us than to the remote star. Hence irregular dimming that doesn't seem to repeat predictably.
Measuring absolute brightness is hard. It would be good to compare the measurement error is in brightness of a reference star of about the same magnitude and distance(and even perhaps a known variable star) to the observed changes in this star.<p>In the lab under ideal conditions with ideal light sources, it's pretty common for there to be >2.5% error in these types of measurements. For those used to dB unit, this is a ~0.1dB change. In optics, it's very easy to introduce error at this level.
My wager: The star is being eaten by a cosmic horror called Hellstar and it will be soon coming our way. Now excuse me while I take off my Junji Ito hat.