[meteorite-list] WHAT IS A PLANET?

[Chris Peterson]

I'm happy enough for now keeping the definition loose. We have nine objects 
that we call planets for historical reasons; I'd be cautious adding more 
until we have a better understanding of their formation. I would lean away 
from calling anything significantly off the ecliptic a planet, unless we 
know that they it formed in the same process that produced the other 
planets.

The reason this whole question comes up is because "planet" has a powerful 
colloquial meaning quite independent of any possible scientific definition. 
Perhaps the best solution is simply to remove "planet" from the table and 
leave it to its traditional use. All we need is a formal definition for 
bodies orbiting stars (possibly on a common plane), with enough mass to form 
near-spherical surfaces (and maybe a few other criteria). Perhaps 
"planetoid" could be used for that.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "Sterling K. Webb" <kelly at bhil.com>
To: "Meteorite List" <meteorite-list at meteoritecentral.com>
Sent: Sunday, July 31, 2005 2:16 AM
Subject: [meteorite-list] WHAT IS A PLANET?


>    These recent discoveries of new "planets" is going to heat up the
> on-going quarrel about what is and isn't a planet, with its increasingly
> long definitions and conditions statements designed to trim reality in
> the mold of the arguer's mind.
>
>...
>
>    So, here goes: if it goes around the Sun and is demonstrably (the
> entire range of error bars above the Ceres diameter) larger than Ceres,
> it's a planet. Welcome to The Club!