A New Theory Reveals Why Tabby’s Star Looks So Bizarre

There’s an unsolved mystery out there in
space. One of many, to be sure, but this is one that
some people really want to blame on aliens because we haven’t had a stronger explanation. I’m talking about Boyajian’s star, or
KIC 8462852 and some new observations that may have just given us the information we
need to say with certainty: Aliens!? Or no? Boyajian’s Star, previously referred to
as Tabby’s star, is named after the astrophysicist who first studied its inexplicable behavior. It’s a bit larger than our own sun, and
is about 1300 light-years away. And it displays behavior that we just can’t
figure out. Actually, it’s the most unusual dimming
of a star ever observed. Its brightness dips in totally erratic and
unpredictable ways. Sometimes just a tiny bit, sometimes by as
much as 22 percent. And here’s the thing—these behaviors can’t
be attributed to most of the things you would think of. The dimming is much too substantial to be
caused by an orbiting planet, because even planets as big as the biggest ones in our
solar system would only make a tiny blip in the brightness of Boyajian’s star. Plus, if it were a planet, we should be seeing
the same dip in brightness at regular intervals as the planet runs rings around that star, but no. Maybe it was a swarm of comets careening toward
the star. But then astronomers found that the star actually has been dimming steadily for years in addition to the unpredictable blips in brightness—it’s
losing its shine, and it’s about 14% less bright than it was a century ago. A comet cloud couldn’t cause something that
gradual. So the lack of any convincing explanation for
its finicky behavior is what gave rise to this idea of energy-generating alien technology,
like a Dyson sphere, which I think is pretty hilarious. It is indeed very tempting to think that the
unpredictable dimming of this star is due to some alien megastructure passing in front
of it to gather power. But a new model from Columbia University may
just give us an answer that doesn’t rely on the existence of a hyper-developed solar-powered
alien civilization. The new theory says that maybe Boyajian’s
star has been a little bad. Like the villain in a Charles Dickens novel,
it may have stolen an orphaned exomoon. This hypothesis is based on the idea that
the star pulled a moon into its orbit from a now long-gone planet, and the poor moon
is now being torn apart by stellar radiation that it wasn’t used to in its previous life,
orbiting merrily around a planet. The resulting plumes of debris from the moon’s
outer layers blow off into the solar system, coming in between the star and Earth, causing—from
our perspective—the occasional, unpredictable dips in brightness. But what makes this theory so tantalizing
is that it also explains the gradual wane in brightness. As more and more of the moon breaks up, the
larger, heavier chunks are getting pulled into orbit with what remains of the original
exomoon. This forms a disk of debris that sticks around,
dimming the star’s light over time. Using models of both exomoon detachment dynamics
and obscuration of stellar light, the team has compiled some pretty convincing evidence
for this hypothesis—and it’s certainly at least a little more credible than the idea
of alien technology. But we still need a bigger sample size to
come to any hard conclusions And we’re in luck, because it turns out—Boyajian’s
star has friends! A new study surveyed more than 14 million
stellar objects, and found 21 stars that also might display unusual, unexplained dips in
brightness. The hope is that this data will allow us to
study these bodies, and look for clues to see if the same mechanism is behind each of
their blinking and winking, and if so, if it just might be this orphaned exomoon theory. That sounds like a pretty cool job. If you want even more on some crazy behavior
of stars that we’re just beginning to uncover, watch this video here, and subscribe to Seeker
for all your stellar exploration news. Let us know what other space mysteries you want us to cover in the comments below, and as always—thanks for watching.

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