Just when you thought it was safe to come up with a new pneumonic for the new 812 planets, the Astronomers strike again...
No, not content with the deliberations of the ad hoc sub-subcommittee of the subcomittee for Naming Names, people are now abusing the power of the Web and coming up with their own criteria.
Let me just note, everyone agrees that hydrostatic equlibrium is necessary for planethood, question is whether it is sufficient.
Stenve Soter has a 22(!) page preprint on astro-ph explaing why the Rose Planetarium position was right all along, and Pluto Should Be Right Out, and no-one else admitted to the Planet Club. [Short version: dynamical dominance is the criterion - as a dynamcist, I admire this criterion, but my initial reaction is to reject it]
Pecnik and Broeg propose a different criterion: that a planet must have an atmosphere. Hm, another temperature dependent criterion, eh?
This has the advantage of keeping Pluto, but we lose Mercury and gain Titan?! Arguable Triton is then also a Planet.
Sorry guys, not falling for it. Mercury may be hard to see in this modern polluted age, but is one of the Original Five Planets. Thousands of Ancient Greeks can't be wrong. Not that wrong.
If a mnemonic is a memory aid, a pneumonic must be a way of sucking information into your brain. I like it.
Ooops.
Er, why yes, I meant to do that!
#$$%20 non-fonetic langvigis
why don't we just keep calling the old ones 'planets' and all members of the new inclusive category 'schmanets'?
Why not make distance from another object of similar attributes a part of the definition of "planet"?
For example: A planet is a natural, non-luminous object circling a star, that lies at least .1 au from any next similar object. ( .1 au being arbitrary - with actual distance subject to the laws of celestial mechanics.)
Gaia sighs: Oh, yea, thats brilliant. Now it depends on where you start counting. So titan can be a planet, but that rules out saturn. Or vice versa.