It appears that to some scientists, pedigree determines whether an object is a true planet or just an "interloper". Size has absolutely nothing to do with the argument. Dr. Andrew Prentice (Centre for Stellar and Planetary Astrophysics) considers "Xena" a likely outcast from what he terms a "hostile" star system. He believes that technically, to be considered a planet an object must orbit on a relatively flat plane with respect to the ecliptic and have a somewhat circular orbit, and by that means that it must have formed about the same star it orbits. Folks, I'm not an astrophysicist or a planetary scientist, but since when did anything but sheer size enter into the equation? I've never heard that place of origin was an important criterion of planethood. We were all taught that small, rocky worlds were for the most part, inhabitants of the inner solar system, the gas giants, denizens of the outer realms. But Carl Sagan got us thinking that the solar system model is just one possibility in a universe of limitless possibilities, and recent exoplanetary discoveries seem to bear this out remarkably well. On Dr. Prentice's grounds, and he freely admits this, Pluto should be cast out of the planetary ranks too (here we go again). Dr. Charley Lineweaver (Australian National University): "Either we have a 10th planet or we have only eight planets." OK, let's take that line of reasoning and extrapolate: An object starts out life as a planet, gets tugged out of the star system it was formed in, and goes wandering about it's part of the galaxy until it falls under the influence of another star- at which point it is no longer a planet, but now just a mere "interloper" (Dr. Prentice's term). Suppose a star that had no planets formed from it's original accretion disk, but has dozens of Xena-sized objects in similar non-uniform orbits. Do future explorers report back to mission control "system has no planets, it's totally barren of planets". The term "planet", then, does not denote an intrinsic quality of an object at all. An object can be a planet, then not a planet, depending on just where it is. And, by extension, does the same logic apply to planetary satellites? Do moons in retrograde, inclined, or highly eccentric orbits need to be struck off the rolls? Obviously they didn't form with the other natural satellites around the same planet, and the size limits for natural satellites have never been rigidly defined, either, to my recollection. It will be interesting to see what definition of a "planet" is finally decided upon. I'm hoping that origin plays no part in it. Call it the "Solar System Statue of Liberty Theory" or SSSLT (copyright 2005). "Give me your tired, your poor, your huddled planetary masses yearning to breathe free, the wretched refuse of your stellar shore. Send these, the homeless, gravity-tossed to me, I lift up the Sun beside the golden door!" ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs