# Let's see... there are 9? No, 10? uh... 12??? planets in our solar system?



## j d worthington (Mar 1, 2008)

Or so it seems by some criteria, anyway. Recently I came across a listing of the planets in our solar system -- in connection with the creation of a mnemonic key to remembering them -- which listed not only those most of us know, but also Ceres and Eris... which, from my understanding (along with Pluto now) are dwarf planets.... Anyway, there may be another one joining the ranks soon, as well:

Japanese scientists eye new planet - Yahoo! News

Title: "Japanese scientists eye new planet", from AFP, by Kyoko Hasegawa, datelined Thurs., Feb. 28, 2008.

I wonder how many more shifts we'll see in this in my lifetime....?


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## Sephiroth (Mar 1, 2008)

I remember the discovery of Eris, and the subsequent debate concerning what is or is not a planet.  There was a (minor) popular outcry at Pluto's 'demotion', but I like the dwarf planet designation.  Pluto never seemed like a 'proper' planet to me.  

This thing they're talking about in Japan is huge, though!  I'd be quite excited if they found that.


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## Pyan (Mar 1, 2008)

From the link...



> Planet X -- so called by scientists as it is yet unfound -- would have an oblong elliptical solar orbit and circle the sun every thousand years, the team said, estimating its radius was 15 to 26 billion kilometres.



An *oblong* orbit? What does it do at the corners?


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## Tillane (Mar 1, 2008)

pyan said:


> An *oblong* orbit? What does it do at the corners?


A very sharp turn?

Interesting stuff, though.  The sheer size of its orbit was what amazed me: a 15 to 26 _billion _kilometre radius?  Blimey.


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## j d worthington (Mar 1, 2008)

pyan said:


> An *oblong* orbit? What does it do at the corners?


 
There are two responses I can make to this. One is to simply say "What Tillane said". The other, more pedantic, is to point out the following:

http://www.merriam-webster.com/dictionary/oblong

And now I've gone and done both....

In other words:

Pyan! *SMACK!*


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## Delvo (Mar 1, 2008)

There's no reason given why they would think there's another "planet" (which this wouldn't be even if it did exist). That plus the name makes it appear that they're talking about the same thing that's already gone by the name "Planet X" for years: a bit of made-up nonsense that's supposed to come into the inner solar system between the orbits of Earth and Venus once every some number of millennia or such, creating lots of disasters and devastation on Earth which mark the end of one era of the world and the beginning of the next. It's been increasingly popular in recent years as one of the more prominent "end of the world" predictions, especially now that it's merged in some people's minds with the "year 2012" stuff.


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## j d worthington (Mar 1, 2008)

Delvo said:


> There's no reason given why they would think there's another "planet" (which this wouldn't be even if it did exist). That plus the name makes it appear that they're talking about the same thing that's already gone by the name "Planet X" for years: a bit of made-up nonsense that's supposed to come into the inner solar system between the orbits of Earth and Venus once every some number of millennia or such, creating lots of disasters and devastation on Earth which mark the end of one era of the world and the beginning of the next. It's been increasingly popular in recent years as one of the more prominent "end of the world" predictions, especially now that it's merged in some people's minds with the "year 2012" stuff.


 
I have to disagree there, Delvo. From the article, it doesn't sound a bit like what you're describing; more an extension of the sort of thinking that led to the discovery of Pluto in the first place. And I don't see anything in there that indicates it's anything even remotely resembling that "Planet X", which is something that's been bruited about for a very long time.... The description here sounds much more like the possibility (or likelihood) of such a planet being out there, based on the information we have currently, including an extrapolated model of the origin of the system. Hardly the "doomsday scenario" sort of thing the mystics are so fond of.....


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## MG1962 (Mar 1, 2008)

What frustrates me - Pluto is a planet in any other system but ours. Basically they chose language and issues they knew was perculuar to Pluto, then decided to use those to proved it wasn't a planet.

Talk about a circular arguement


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## Pyan (Mar 1, 2008)

j. d. worthington said:


> There are two responses I can make to this. One is to simply say "What Tillane said". The other, more pedantic, is to point out the following:
> 
> oblong - Definition from the Merriam-Webster Online Dictionary
> 
> ...



Ouch!
But I must say, I've never heard of this as a definition of oblong...I thought of it as being the Euclidian model....



> Of quadrilateral figures, a square is that which is both equilateral and right-angled; an oblong that which is right-angled but not equilateral; a rhombus that which is equilateral but not right-angled; and a rhomboid that which has its opposite sides and angles equal to one another but is neither equilateral nor right-angled. And let quadrilaterals other than these be called trapezia.


I would have thought that an orbit this shape would be _ellipsoidal_....However, I stand corrected.


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## matt-browne-sfw (Mar 1, 2008)

Classifications and taxonomies do change over time. To me the introduction of planemos and dwarf planets made a lot of sense.


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## Pyan (Mar 1, 2008)

matt-browne-sfw said:


> Classifications and taxonomies do change over time. To me the introduction of planemos and dwarf planets made a lot of sense.


Especially as Eris   is bigger than Pluto, anyway, so it seems a new definition was needed.


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## j d worthington (Mar 1, 2008)

I definitely prefer the term "dwarf planet". I'm afraid "planemo" strikes me as simply an ugly neologism....


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## Ursa major (Mar 1, 2008)

Presumably a larger, Jovian-size planemo would be called a planemojo.


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## j d worthington (Mar 1, 2008)

Ursa major said:


> Presumably a larger, Jovian-size planemo would be called a planemojo.


 
All right... _that_ one should be a banning offence!!!


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## Urien (Mar 1, 2008)

But if you ban Ursa Major then he'll have lost his mojo.

Yeah baby yeah.


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## The Ace (Mar 1, 2008)

I was never happy with Pluto not being a planet, which would mean that Eris is automatically one, but Ceres ? the thing's tiny.

Planet X would raise the total to 11.


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## j d worthington (Mar 1, 2008)

The Ace said:


> I was never happy with Pluto not being a planet, which would mean that Eris is automatically one, but Ceres ? the thing's tiny.
> 
> Planet X would raise the total to 11.


 
Eh? Hmmm, perhaps I wasn't clear. The mnemonics I've come across include Pluto, Eris, and Ceres... so Planet X would make the total 12... no?


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## Urien (Mar 1, 2008)

I bet there are gazillions out there. How far out can the sun hold a planet?


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## j d worthington (Mar 1, 2008)

andrew.v.spencer said:


> I bet there are gazillions out there. How far out can the sun hold a planet?


 
You're probably quite correct; and that far out (the orbit of Pluto and beyond), we're going to be discovering lots of the things in just the next few years, I would imagine. Had someone suggest that we should memorize all the planets/dwarf planets/etc. in our system, but somehow I don't think that's very likely to happen.....


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## The Ace (Mar 1, 2008)

Anyone counting Ceres as a planet has problems, the thing's an overgrown marble.  What next, Vesta ?


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## j d worthington (Mar 1, 2008)

The Ace said:


> Anyone counting Ceres as a planet has problems, the thing's an overgrown marble. What next, Vesta ?


 
Don't give 'em any ideas, Ace... don't give 'em any ideas.....


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## Urien (Mar 1, 2008)

When I was a kid my dad used to add water to Vesta curry powder to make a delicious after work dinner.


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## The Ace (Mar 1, 2008)

I can accept all of that, except, 'Delicious.'


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## Urien (Mar 1, 2008)

I think it was in the days before food was invented. He also used to like Fray Bentos steak and kidney pies, the ones that came in large flat tins.

I think a planemo should be called Fray Bentos. In fact I think I'll call my secret Oort cloud base Fray Bentos.


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## Dave (Mar 1, 2008)

The Moon should be classed as a planet, the Earth-Moon system being binary.

There are theories that suggest that there should be some large mass beyond Nepture to account for irregularities in the orbits of the other planets, but I thought that was now explained by the Oort Cloud.


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