Re: "Pluto Now Called a Plutoid"

Brett Paul Dunbar wrote:

In message <nI2dnQje4vHry_3VnZ2dnUVZ_srinZ2d@xxxxxxxxxxxxx>, Erik Max
Francis <max@xxxxxxxxxxx> writes
Brett Paul Dunbar wrote:
Pluto isn't a planet because it hasn't cleared its orbit Neptune
has. Neptune has cleared that region of space of debris, what's left
either orbits Neptune (e.g. Triton the second largest object in that
region), is in a resonance with Neptune (e.g. Pluto, the third
largest object) or is a transient (e.g. various Comets).
More accurately and succinctly: Pluto is no longer a planet because
the IAU said so. Their "objective" definition was so vague that they
had to include a list of planets to make sure people knew what
modifications that entailed, and Pluto wasn't on it.

No that is actually totally wrong. The definition is entirely
unambiguous, given the sheer size of the gap. On either the
Stern-Levinson parameter or Soter's Planetary discriminant, the gap is
about five orders of magnitude.

Neither of these measures is mentioned, even indirectly, in the IAU's resolution regarding Pluto or any subsequent IAU resolutions. So, so what?

The number of objects classified as planets was small enough that it was
possible to list all the known objects that meet the criteria, listing
examples can be useful and there are only eight known so it was entirely
practical to list all of them. The definition of a Dwarf planet on the
other hand is far less clear for example Vesta appears to have become
spherical, solidified then been distorted by as massive impact, it is
unclear whether that is a dwarf planet or a small solar system body.

You're making my point for me.

Stern's objections are more terminology than content, the IAU definition
matches what he calls an überplanet, clearly he finds the class itself
useful even if he isn't happy about the name.

So the references you're using to back up the IAU disagree with the IAU's resolution and new classification system. Ironic.

--
Erik Max Francis && max@xxxxxxxxxxx && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
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-- Heinrich Heine
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