This is an update in my continuing coverage of the
mysterious star KIC 8462852 or Tabby's star for December 27, 2016 . For the full back story, I suggest
checking out my other videos on this channel starting with my first update video
from April of this year and my subsequent updates on this star.
At this stage the star is being monitored every night for
the expected deep dimming events first observed by the Kepler Spacecraft. And
while there have been a few false alarms, Tabby's star has remained stable in
brightness since the observations began earlier this year. And while it's
overwhelmingly likely that we're seeing a natural phenomenon, the alien
megastructure hypothesis is still not discounted. But the natural explanations
that are emerging are improving in quality and we seem to be moving closer to a
consensus on what's going on here. But, there is dissent, more on that in a
minute.
But which natural phenomenon is causing it? Several new
theories and papers have emerged that may provide an answer. According to a
recent paper by Jason Wright of Pennsylvania
State University
Category one: The Solar System
To cause the dips in brightness that Kepler observed with
KIC 8462852, you need some kind of material to block the light. This could be
anything, including alien megastructures. But the location of that material can
be anywhere in between us and the star.
One idea is that there is a small, dense cloud of material
in the outer solar system orbiting the sun and passing by and blocking the
light from Tabby's star. While a reasonable idea on its face, this stands out
as odd because we've never seen an analogue of this cloud of material passing
in front of any other star in the millions of observations we've made of the
galaxy. Because of that we have no real reason other than conjecture to suspect
that such a cloud might be lurking out there.
A second possibility is that there is a Kuiper Belt object
passing near the line of sight of the star that happens to be out gassing
material, such as Enceladus does with water or even Io with its volcanoes. In
other words, something spewing material into space. This would seem unlikely,
you'd need a bunch of conditions to be just right for a geologically active
world to exist in the Kuiper Belt. It would also need to be doing it in a way
that's obscuring KIC 8462852. That's a tall order. But, as Pluto recently
showed us, bodies in the outer solar system can be quite active and weird stuff
does happen in our solar system. So, this remains a maybe.
A third possibility that hasn't been well fleshed-out is a
slow collision of comets in the Oort cloud releasing the material. If that's
the case, it would probably be obscuring more than just Tabby's star, so it's
not a great solution.
But all possibilities involving our solar system face two
serious hurdles. Boyajian's star lies well outside the ecliptic plane where the
vast majority of matter is congregating. While it's not impossible to have
material outside the ecliptic, it's definitely there, it does disqualify most
material. The further you are out of the ecliptic, the less stuff there is to
block light.
The second problem is that there is some evidence, albeit
weak, of potential periodicity in the material that was causing the dips in
brightness that Kepler observed. In other words we may have seen it pass by
multiple times during Kepler's run. This is to say that there are indicators
that the material is orbiting Boyajian's star. But it's really weak evidence.
More observation is needed to confirm this. Think of it as hints of being in
orbit, not proof.
Category Two: Material in the interstellar medium
The possibility of periodicity also affects any solutions in
this category. If confirmed, it would eliminate any possibilities here.
However, as it stands, it's still possible that some sort of material is
passing in deep space between us and KIC 8462852. The nature of this material
is debated, it could be dust or gas and could be linked to any number of
astronomical phenomena. One theory even proposed that the material is located
in the accretion disc of a black hole. However there are problems with all
theories in this category for one simple reason: if it is a cloud of
interstellar dust, it's a very strange one of a type we've never seen before.
We've never seen one create the kinds of dips Kepler observed.
It's not impossible, of course, but it is unlikely.
Unfortunately, with all explanations on the table for Tabby's star, they all
seem unlikely. The only consensus is that whatever this is, it's a very rare
event and that's what makes pinning it down so difficult.
Category Three: Material in orbit around KIC 8462852
If periodicity is confirmed, this becomes the most likely
set of solutions. The problem here is that all of them are really unlikely
given what we've observed and because of that the potential for alien
megastructures being the culprit remains on the table. But as with anything in
astronomy, the last explanation you want to jump to is alien activity. While
it's true that we really don't know how common aliens are, the Fermi paradox
makes it safe to assume that aliens are very rare or we would have seen them by
now.
It's also important to remember that we know absolutely
nothing about alien megastructures because we've never seen one of those either.
Trying to figure out what sorts of structures a civilization more advanced than
our own would build is purely conjectural. We can theorize and speculate, but all
we can really define with any certainty is that the megastructures can't defy
the laws of physics.
Because of all the uncertainty, megastructures end up being
a wide open explanation that can fit almost any strange phenomenon we observe
in the universe. That's why we have to be very cautious when discussing that
possibility. It's possible, but not a very good explanation for KIC 8462852.
The natural explanations in this category advanced so far
range from disintegrating giant comets to smashed planets. I've covered these
in my previous updates in depth, so check those out for the back story, but
needless to say none of the explanations are very good. All of them in this
class have fundamental problems based on what we've observed.
Category Four: KIC 8462852 itself.
But a new paper suggests something more solid. It presents that Tabby's star is undergoing an internal phase shift that's messing with the light that it emits. A group of mathematicians and scientists at the
Think of it as the snaps you hear in a stick as you bend it just before it breaks. The scientists suggest that the small dips in the Kepler light curve are related to the larger dips in such a way that they are linked. This is super-important because it's the first real blow to the megastructure explanation. If the smaller dips are related to the huge dips, then the constraints placed on the alien megastructure theory shrink in a major way.
At that point, it would appear that the star is to blame and that we've caught it in a very rare, but very weird situation where stellar flares and internal conditions of the star are just so that its brightness is being affected in a strange, but entirely natural way. Their model seems to be consistent with what's been observed. Only time will tell if this theory holds up.
But that's not the only paper that's come out recently. German mathematician Eduard Heindl recently proposed that a specific type of alien activity would be consistent with what we see at Boyajian's star. Known as stellar lifting, this conceptual technology would allow a civilization to mine the resources of their star for raw materials.
This may sound like science fiction, but in reality we can think of relatively straightforward theoretical ways to lift material from a star and cool it for use using mirrors, localized heating, and magnetic fields.
Heindl's theory is noteworthy in that it mathematically explains a very strange feature located in the light curve that has so far not been particularly explainable using natural means. The feature is unusually smooth and while not impossible comets and dust clouds would have a hard time creating it. But then again, just about everything we know about KIC 8462852 tells us that whatever we're seeing, it's incredibly rare and unusual.
So there you have it, observations of the star are ongoing
but the mystery of Boyajian's star is not yet solved. My transcript for this
video can be found at my blog the Event Horizon, link in the description below.
You can also find links there to the scientific papers I referenced in this video
for people that want to dig in deep regarding this story as well as regular
posts about technology, interesting articles I find, and just science and
technology stuff in general.
Thanks for listening, I am science fiction author and
futurist John Michael Godier currently with a new book coming out in a matter
of weeks. It's called Supermind and I'm happy to finally unveil the cover art
by noted space artist John Kaufmann, link to his website in the description
below and be sure to check out my other books at your favorite online retailer
and subscribe to my channel for regular, in-depth explorations into the
interesting, weird and unknown aspects of this amazing universe in which we
live.
The papers cited in this video:
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