Stars are fairly predictable. Our telescopes detect when they brighten and dim, and we usually have a plausible explanation why. Usually, it comes down to planets orbiting and temporarily blocking our line of sight.
But every now and then a star dims so erratically that neither amateur nor professional astronomers can make sense of it. That’s the case for KIC 8462852, or Boyajian’s star.
The star’s brightness has dimmed as much as 22% since it was first observed by the Kepler telescope several years ago. Astronomers haven’t observed this behavior on any other star before, so naturally it brings about many interesting theories. Here’s Delaney Chambers, writing for National Geographic:
Theories abound as to what’s going on. Among the most popular are that comets are passing in front of the star, or that a nearby planet has broken apart, blocking our view from Earth with fragments of planetary matter.
Some scientists theorize that the dimming could be due to an “alien megastructure” that’s orbiting Boyajian’s star and harvesting its energy.
In the last month, Boyajian’s star dimmed not once but twice, first on April 24 and then again on May 19.
Scientists are maintaining their round-the-clock observations of this mysterious star to hopefully discover, once and for all, why it dims the way it does.
For more details, read our earlier coverage on Boyajian’s star.