How many planets?

[Agafaster]

I see the backlash has already started !!

my personal take:

Pluto is not a planet. its too small, there are other objects that arent automatically planets that are the same size, or bigger, such as 2003-UB313 'Xena' (what a crap name!)

I reckon on the Earth and Moon being a double planet - ok, it fails the barycentre test, but my opinion is based on the sheer size of our moon, and relative to the earth too. no where else has a moon this big in relation to the primary body.

There is a problem with the definition: 'must have cleared its orbital neighbourhood of other objects' this is done by either swallowing up these objects, or ejecting to another part of the solar system - this falls down when we consider that the earth, mars and indeed Jupiter have objects in their Trojan positions... ie: around the L4 and L5 Lagrange Points. does this now mean these 3 are not planets ?!

the battle rages on!!

[Agafaster]

Tigger wrote:

Agafaster wrote:

I reckon on the Earth and Moon being a double planet - ok, it fails the barycentre test, but my opinion is based on the sheer size of our moon, and relative to the earth too. no where else has a moon this big in relation to the primary body.

Charon (Pluto's moon) is significantly bigger in proportion to Pluto.  
    -Tig

True, but since Pluto isnt a planet, Charon isnt a moon (open floodgates!) - so The Moon is the largest moon in our solar system ;-) and in relation to its primary too!

[Agafaster]

isnit ?

-checks wikipedia-

bloody hell! you're right, I sit corrected !
it is the 5th largest though, and I stand by the ratios thing, and the nitpicky that charon isnt really a moon.

[Agafaster]

Arthur C Clarke predicts that the core of Jupiter could be an enourmous diamond - a piece of this is found on the now melting moon Europa, in his books 2010/2061.