Planet 9 Update for 10/15/2017


This is an update in my continuing coverage
of Planet Nine, a suspected large planet that could be lurking out in the far reaches of
the outer solar system. Evidence continues to mount for its existence
through its gravitational effects, and if it’s there, visual discovery could come at
any time. There are now five separate reasons to suspect
the existence of Planet Nine. In a 2016 paper by Michael Brown and Konstantin
Batygin, link below, they lay out the first three indicators that something big lies far
out beyond the orbit of Neptune. The first of these is a set of six objects
in the Kuiper belt, basically floating chunks of ice and rock. All six of these objects have elliptical orbits
that point in the same direction. That’s a pretty unlikely arrangement, the
orbits out there should be all over the place. The second indicator also involves these objects,
in addition all six objects are in orbits that also tilt out of the solar system’s plane. These two clues on their own would indicate
that there may be a large gravitational source out there, such as a planet. The third indicator comes from computer simulations
predicting that more objects in the outer solar system should be tilted out of the plane
in a characteristic way. Brown and Batygin then realized that several
such objects were already known. The fourth clue involves the solar system
itself and somewhat of a mystery regarding it. The solar system is arranged on a plane and
barring gravitational disruption in the past, the major planets orbit within it, thought
to originally be the plane of the original protoplanetary disk the solar system formed
from. The plane of our solar system is strangely
tilted by about 6 degrees in respect to the equator of the sun. Until now, no one was certain why this is
since it should be about level with the sun’s equator. In another paper, Elizabeth Bailey, link below,
presented that this could be due to Planet 9. Over time, its effect would make the solar
system’s plane wobble slightly, explaining the discrepancy. The last indicator is a group of inner Kuiper
belt objects that orbit the opposite direction of everything else in the solar system. Planet 9’s gravity would provide a ready explanation
for that as well. These five indicators, as Batygin states in
a NASA press release, actually make the solar system look extremely strange without the
presence of Planet 9. But it would need to be distant, as much as
20 times further out than Neptune and there are competing viewpoints that all of this
could be due to a chance arrangement of objects in the outer solar system, though that idea
seems to be losing steam. But where did this distant outlier planet
come from? There are two possibilities. Another mystery planet nine might solve is
why one of the most common types of exoplanet in the galaxy happens to not be present in
this solar system: a super earth. It may be that the solar system does have
a super earth, but rather than staying in the inner solar system, it may have migrated
outward early in the solar system’s history. Or, alternatively, it may never have been
closer to the sun, instead it might be an exoplanet that the sun captured at some point
from another system. In which case, if we find planet 9, do we
class it as a planet of our solar system or an exoplanet addition? If it did form near the sun, might it be a
preserved frozen remnant of the early solar system, or might it be a geologically active
place like Pluto? Could it have enough radioactive decay in
its core for liquid water, even far out in the Kuiper belt? Or alternatively, if its not from here, might
it some day give us clues on what planets from other solar systems are like? Thanks for listening! I am futurist and science fiction author John
Michael Godier currently hoping they find planet nine soon so I can eye it suspiciously,
it could be an alien freeloader planet from another star system and be sure to check out
my books at your favorite online book 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.

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