Planets and Plutons - IAU Draft Definition

If this goes ahead, and they classify charon as a planet or a pluton, then maybe our moon should become our nearest planet, after all it is bigger that pluto and some people consider the earth moon system a double planet also.
Perhaps a "definition" of double planet is on the cards also

Why can't we just leave it alone? I'm leaning towards the cultural side of this argument rather than the purely scientific. I mean we all know at this stage that there are other objects as large as Pluto.
It's just going to confuse the general public. And it's going to ruin my favourite memory aid:

Many Very Earnest Men Just Stood Under Nelsons Pillar

Sounds a bit naff to me to be honest. The further out these planets or plutonians or whatever they are called, the more difficult it will be to judge their size and orbit. It could take years to confirm whether an object is a new planet or not, especially if it's borderline on this specificed figure. If it then does become a new planet, all the maps etc change again.

Not to mention that the average Joe will have no chance of actually seeing any of these planets.

Hi,
Here's part of the statement from the IAU at Prague:

The part of "IAU Resolution 5 for GA-XXVI" that describes the planet definition, states "A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet." Member of the Planet Definition Committee, Richard Binzel says: "Our goal was to find a scientific basis for a new definition of planet and we chose gravity as the determining factor. Nature decides whether or not an object is a planet."

Good in theory as one criterion, but having dozens of potential "planets" is daft!

Better if they had defined 2000km diameter as the lower limit. The advantages would be:

1. We would not have the anomaly that Ceres is a "planet", but Pallas or Vesta cannot even be called a "minor planet"
but a "minor solar system object".

2. Charon would be left as a moon, not a planet.

3. Pluto would still remain a planet.

4. 2003 UB313 would be a planet, along with some others that presumably will be discovered.

5. Most objects above 2000km diameter are spherical.

6. The 2000km would limit mean people would be able to name the planets. Imagine school children of the future trying to remember 53+ names!

I would urge IAU Members to vote against such a proposal.

John

Think we're too late to create an effective lobby? :lol: