So... how many planets, again?

I heard it as a done deal on the radio this morning, but apparently the vote hasn't happened yet-- IAU to decide on new planets. The draft to be voted on defines a new subset of planet-like bodies, plutons, with the immediate inclusion of Pluto (of course); its orbital buddy, Charon; Ceres, the largest body in the asteroid belt, and a third body, 2003 UB313, nicknamed Xena.

to be fair Pluto is rather odd....

smaller than our moon, and many other moons in the solar system. it's moon is far larger (proportionally) than any other.

it takes an odd, skewed elliptical orbit that is also out of the plane of all the other planets (17 degrees out, where as the highest other ris mercury, which sometimes gets as far as 7 deg. out).

all in all it's nothing like a planet.

I belive though that it has a metallic core like other planets. If I'm not mistaken.

They also have made a definition finely for what is a planet???
According to this definition, two conditions must be satisfied for an object to qualify as a planet:

* The object must be in orbit around a star, but must not itself be a star
* It must have enough mass for the body's own gravity to pull it into a nearly spherical shape.

?do not most of our moons meet this?(since they plan to add Pluto's moon)
Love astronomy. hate their rules/definitions, so loose.

Pluto is also very hard to predict, orbit wise.

with both Newton's basic forces & motions laws and Einstein's rather complex laws, it is still hard to predict where Pluto will be exactly. where as with most other celestial bodies we can work out that they will be in X, Y and Z a position at precisely 14 minutes past 3 in the after noon, greenwich mean time, on the 18th of January in the year of our lady 14,387 ad (I use Lady because by this time religion will probably have evolved [yes, religion's DO evolve, just like everything else] to accommodate a female primary deity).

meh.

random fact, did you now that the greater majority of solar systems are binary? ours is rather more unique than we give it credit .

Pluto and Charon are unique in that they are nearly the same size-- it is more of a binary planetary (or plutonary, as it were) system than a planet with orbiting moon.

it is indeed. although they are far smaller than anything else really important in the solar system, they in fact have the lowest ratio in mass (~8.6 : 1 [kg]).

and they're constantly facing the same way to each other.

very odd indeed.

Trans-Neptunian object (TNO) - objects that orbit the sun at an average distance that is
greater than Neptune. Pluto and its moon Charon are Trans-Neptunian objects. Since 1992
more than 1000 TNO objects have been discovered.

Some of the Trans-Neptunian objects:

I honestly think that they should keep the solar system the way it is. 9 planets. they way we learned it in middle school.
"My Very Eccentric Mother Just Served Us Nine Pickles". Great way to learn the planets.(note the first letter of each planet starting every word.) What are we going to do, make a whole story out of that now becuase there are so many more planetary objects being added that for all we know could just be a very large asteroid or a comet? Or even just a stray planet core from when our galaxy was still young. Besides if this vote does go forward and become successful, it would take millions and millions of the taxpayers dollars to update every science book and re-publish books and make new books about these new planetary objects. No. We should keep the solar system the way it is.