If you asked me, I’d say that Xena is named after much cooler character than Pluto.
How about Merkin Muffly?
Anyhoo, yeah, what about Sedna? Well, looks like it might make the cut, should this new definition of planet become the official one.
OK. I can live with the idea of additional planets but no one has answered the most important question: What will be the mnemonic we will use to remember the order of the planets? Right now I use, “My Very Excellent Mother Just Served Us Neat Pizza.” What the hell are we going to use now??
It’ll be a paragraph long, probably. I’m hoping kids won’t be expected to memorize all the planets. Maybe the questions will be along the lines of “Can somebody name a gas giant planet? How about a rocky planet? What are two planets in the Kuiper Belt? Can someone tell me where the Oort Cloud is?”
P.S. - The Sedna article reminded me of something: It’s hypothesized a Neptune-sized planet may be out there, way out there, and may be involved at least partly in knocking future comets out of their orbits and into the innner solar system. There very well could be all kinds of crazy stuff out there.
“My Very Excellent Master Chef Just Served Us Neat Pasta Con Pesto.”
(That assumes that 2003 UB313 is renamed Persephone).
Something nobody else has mentioned, but what about the astrologers? They have it hard enough as it is figuring out what planet is in each “house”, and how they all affect each other and us. If you add all these new planets, you’re just making their job that much harder.
Nope, this is a bad idea on so many levels.
Wasn’t “Uranus” a Greek god?
But you’re write, the general populace would murder the pronunciation of Persephone.
I know a lady that, despite having seen all the Harry Potter movies, still insists on pronouncing Hermione as Her-Me-Own.
I deserve a flogging for that one “but you’re right”. More coffee! :smack:
I find the spherical requirement a little odd. So Ceres is big enough to be roughly spherical. Vesta is not. But none of the planets is truly spherical- exactly how do you measure sphericity? By ratio of greatest diameter to least diameter?
And what of Pluto and Charon? Do they count for two just because their center of gravity is outside Pluto? Is the criteria that if the c.g. is within the planet, then you have a satellite but a c.g. outside the primary planet makes for binary planets?
On the bright side, until they discover more “plutons” this means that the number of planets exactly matches the number of constellations in the zodiac.
Won’t somebody think of the Starchildren?
On the subject of “sphericity”: Yeah! I mean, Saturn especially is not a sphere, but rather an oblate spheroid. It’s visibly squashed at the poles, even through relatively modest telescopes, a function of its breakneck rate of rotation. Perhaps some range of ratios of polar and equitorial diameter will be necessary to include in the definition.
Contributed by someone in the lab here:
Mary’s Violet Eyes Make Celibate John Sit Up Nights Playing Counterstrike (Xbox)?
Nothing will ever be worse than Uranus, a.k.a. The Planet Whose Name You Can’t Say Without Laughing.
Well, the IAU doesn’t specify sphericity exactly, but rather they say that:
So basically, anything that has enough of its own mass to be approximately spherical, if we negate things like rotation on its own axis that tend to flatten the poles and make the equator bulge, will be classed as a planet. The IAU give an approximate mass and diameter lower limit for this too – anything that’s more massive than 5 x 10[sup]20[/sup] kg and has a diameter greater than 800 km. They say that anything that’s borderline will be evaluated on a case by case basis.
Yep:
i.e. if you have a mulitple object system, the largest of the objects is classed as a planet if it satisfies the conditions for a planet. If you have two objects in the same system that satisfy the conditions for planets (e.g. Earth-Moon or Pluto-Charon), then if the common centre of mass lies within the larger body, (as is the case of Earth-Moon), then you have a planet (the Earth) and a satellite (the Moon), since the smaller body effectively rotates around the larger one, whilst the larger one simply wobbles a bit on its axis. If however, the common centre of mass lies outside the larger body, as is the case with Pluto-Charon (where the barycentre is ~1000 km above the surface of Pluto), then both objects rotate around that common point, and you have a binary planet.
I’ve already seen astrological forecasts involving Chiron, so Ceres, Sedna, Quaoar, “Xena”, etc, probably wouldn’t be too difficult to add. The main problem would be creating additional symbolism for them.
I notice that very little of this discussion mentions an upper size/mass limit for planets. Has the IAU shelved that discussion, or what?
Many of the gods are used up in moons. It would be necessary to list them all and see whats left. Then what would be majesic or descriptive enough. I am afraid we would wind up with a pretty minor diety. I am not quite ready to go to tv programs though. Planet Hawkins or Einstein would appeal.
I guess anything large enough to sustain or have sustained nuclear fusion of hydrogen in its core through the heat generated by gravitational pressure is a “star”. Anything smaller appears to be either a “brown dwarf” and/or a “planet”. I don’t think there’s a clear delineation between brown dwarfs and planets. I don’t think Jupiter is anywhere near massive enough to be considered a brown dwarf, but many of the exoplanets discovered are bigger, a few considerably so. Are the big ones “planetary brown dwarfs”? I dunno. I think I read somewhare that some brown dwarfs are large enough to briefly sustain fusion of heavy isotopes of hydrogen or maybe even some heavier elements like lithium. Maybe that will be the line of demarcation, I don’t know.
You could have gods (and goddesses) from TV programs, such as Belldandy.
Astrology of minor planets:
At one point in grad school we considered whether there would be extra money involved in casting such horoscopes. We decided radio astrology was much more promising. 
Ceres already has its own symbol from its first period as a planet. See about midway through the page:
http://aa.usno.navy.mil/hilton/AsteroidHistory/minorplanets.html
I think one of the very first volumes of Astronomical Journal has the article wherein the community officially gave up on unique symbols for each asteroid and began the practice of putting the asteroid number in a circle.