The Mysterious Tabby's Megastar Just Dimmed Again—Are Aliens Making Contact or Is It Just 'Cosmic Dust'?
Though KIC 8462852, also known as Tabby's star, is probably not host to an alien megastructure like a Dyson Sphere or an orbiting solar panel array, it's pattern of brightening and dimming is still puzzling astronomers. We now know that space dust is probably the culprit, but there's something strange about this dust and how it's interacting with the star.
We can learn a lot about objects when they pass in front of stars—the transit method is probably the most popular means for identifying potential planets, for example. The temporary dimming in a star's light can shed light on the composition of the object passing in front of it, and the pattern of dimming can tell us something about the object's orbit. In the case of Tabby's Star, we're dealing with clouds of dust, not planets, however—and the pattern of brightening and dimming is very weird.
The star had its biggest dip in brightness since 2013 about 10 days ago, then rapidly returned to normal.
There are a couple potential hypotheses floating around for what's causing the dust around the star to behave this way: first, asteroid impacts may have caused very large dust clouds to float around the star. Second, a single big collision, on par with the impact that may have created Earth's Moon, may have thrown up a large cloud of dust. Third, there might be small objects surrounded by dust orbiting around Tabby's Star.
The most interesting hypothesis, however, is that the dimming is caused by the remains of a partially broken comet with a backward-facing tail.
According to LiveScience:
"This hypothesis matches the star's dimming patterns if you assume that whatever broke up the comet hit it with enough force to "kick" its tail forward. If the particles in the tail are large enough, they could maintain that backward-comet orientation even against the electromagnetic forces of the star, the researchers wrote."
You can follow the latest updates on Tabby's star here.