[extropy-chat] SPACE: How many planets?

[Harvey Newstrom]

On Monday, March 22, 2004, at 02:23 pm, Mike Lorrey wrote:

>
> --- Brent Neal <brentn at freeshell.org> wrote:
>>  (3/22/04 5:12) Robert J. Bradbury <bradbury at aeiveos.com> wrote:
>>
>>> Space Daily has an interesting article this morning on how
>>> to settle the is it or isn't it a planet debate (I'll spoil
>>> the article to some extent by providing a summary -- if it
>>> has enough gravity to round itself but not enough to start
>>> nuclear fusion its a planet).
>>>
>>
>> This is new take on the debate I read. I think he leaves out some
>> interesting physical criteria that could be used in combination with
>> others, but the "roundness" one that he mentions is one I'd not seen
>> before. Of course, when it comes down to it, the final solution will
>> be 'political' in some sense, since the IAU will pick the rules to
>> create the outcome they find desirable. :)
>
> Actually, roundness was the primary criteria I had stated here not so
> long ago...

I think the orbit plays a bigger role, not only in defining planets and 
planetoids, but also moons which are not usually considered planets.

Here is my scheme:

1.  Planets are in unique orbits as the primary object for that orbit.

2.  Planetoids or asteroids are in belts with a lot of objects in 
similar or close orbits.

3.  Irregularly-shaped rocks that are too small to be rounded are just 
"rocks" or "debris".  I like to use the term "planetoid" for large 
rounded ones, and the term "asteroids" for the small irregular ones.

Therefore, we have eight planets.  Earth is an inner planet.  Jupiter 
is an outer planet.  Pluto is a Kuiper belt planetoid.  Ceres is an 
asteroid belt planetoid.  Sedna is an Oort Cloud planetoid.

I would even extend my bias to moons.  Earth has a moon.  Mars has two 
captured asteroids.  Jupiter has four moons and a bunch of captured 
asteroids.

--
Harvey Newstrom, CISSP, CISA, CISM, IAM, IBMCP, GSEC
Certified IS Security Pro, Certified IS Auditor, Certified InfoSec 
Manager,
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