
Curious tilt of the sun traced to undiscovered planet - noyesno
http://phys.org/news/2016-10-curious-tilt-sun-undiscovered-planet.html
======
noyesno
I don't know about you but I find it incredible that while we can see galaxies
formed 13 billion years ago[0], we have completely missed the existence of a
large planet in our own solar system.

I can only guess what kind of theories the Nibiru/PlanetX[1] enthusiasts will
cook up based on this announcement.

[0] [http://www.space.com/32150-farthest-galaxy-smashes-cosmic-
di...](http://www.space.com/32150-farthest-galaxy-smashes-cosmic-distance-
record.html)

[1]
[https://en.wikipedia.org/wiki/Nibiru_cataclysm](https://en.wikipedia.org/wiki/Nibiru_cataclysm)

~~~
amelius
Also, since the article says:

> It continues to amaze us; every time we look carefully we continue to find
> that Planet Nine explains something about the solar system that had long
> been a mystery

Why hasn't the existence of an additional planet been hypothesized before?

~~~
kartikkumar
It's not that it hadn't been hypothesized before, it's rather that the numbers
that they attribute to this hypothesis stack up well against a lot of Solar
System observations. In other words, the hypothesis is not merely that there
is another large, undiscovered planet in the far reaches of the Solar System,
but rather the details of its mass and orbit that make this a compelling case.
Part of the reason that this hypothesis wasn't possible before is because the
observational data to support these numbers was lacking. The amount of
knowledge we've gained about the Kuiper Belt over the last decade or so is
phenomenal and drives our understanding of what might have happened in the
early Solar System. It's worth reading the original paper to get a handle on
the rigour with which this hypothesis has been analyzed and the coupling with
observations of the Kuiper Belt [1].

[1] [https://arxiv.org/pdf/1304.5166.pdf](https://arxiv.org/pdf/1304.5166.pdf)

~~~
CoryG89
I think this is the same as the hypothesis for Planet X that has been around
since the 90s. Seems like they've just modified it slightly. They take
observations they can't explain, and then make something up out of thin air
that will explain the observations.

Not saying this is a bad strategy, just that in my view it's not much
different from hypotheses for additional planets which have come before.

------
dzdt
If you are just coming to the Planet Nine story, the best background
information is the scientists' blog at www.findplanetnine.com.

------
Tepix
See also: [http://www.space.com/34448-planet-nine-solar-system-
tilt.htm...](http://www.space.com/34448-planet-nine-solar-system-tilt.html)

------
dhruvasagar
Instead of it being a 9th Planet (formed along with others as our solar system
was created), it's perhaps just an enormous object (black hole?!) whose
gravitation causes the sun to tilt ?

~~~
dhruvasagar
Does the sun's tilt match it's position within the milky way galaxy ?

~~~
tempestn
I'm going to assume both of these options have been considered and ruled out.
Also, the article mentions that this Planet 9 explains the orbits of Kuiper
belt objects as well.

------
hanoz
Is there any reason, apart from not knowing exactly where to look, that we
can't find such a planet by watching for when it passes in front of stars?

~~~
KMag
I'm not an astronomer, but I imagine there are too many small untracked
objects, between Mars and Jupiter for instance, that periodically occlude
stars. I imagine the signal-to-noise ratio is too high to start a search every
time something blocks a star. How many millions of times per day must an
asteroid somewhere block a star as visible from Earth? Gravitational
perturbations are a smaller signal, but the signal-to-noise ratio is better, I
imagine.

~~~
hanoz
Maybe although I make a 10 times the size of earth planet at 20 times the
distance of Neptune equivalent to a 77km wide main belt asteroid, so maybe not
all that noisy. Plus the predicted orbit tilt must help a lot. Sounds like a
doable big data problem to me.

