[meteorite-list] And the winner is-- PLUTOID!

[Sterling K. Webb]

Hi, All,

    First, what does the suffix "-oid" MEAN?

http://dictionary.die.net/-oid
    from Webster's Revised Unabridged Dictionary (1913):
"-oid \-oid\ [Gr. ?, fr. ? form, akin to ? to see, and E. wit:
   cf.F. -o["i]de, L. -o["i]des.]
   A suffix or combining form meaning like, resembling, in the
   form of; as in anthropoid, asteroid, spheroid."

>From http://www.answers.com/topic/oid-1

    "1. Used as in mainstream slang English to indicate
a poor imitation, a counterfeit, or some otherwise slightly
bogus resemblance."

    and

    "-oid is a suffix much used in the sciences and mathematics
to indicate a 'similarity, not necessarily exact, to something else'.
According to the Oxford English Dictionary, -oid is derived
from the Latin suffix -oides taken from Greek and meaning
'having the likeness of'." (This is a re-working of the Oxford
English Dictionary's definition by the Wikipedia.)

    As a result, while "Plutoid" is a possible term of definition,
the planet Pluto itself CANNOT be a "Plutoid"! The headline:
"Pluto Now Called a Plutoid" is a gross mis-understanding
of the meaning of the word. Not even the IAU says that. It
says Pluto is a prototype for a class of objects to be named
"Plutoids." They are named "Plutoids," not Pluto itself.

    The term "Plutoid" defines an inclusive class of objects that
superficially or fraudulently resemble Pluto but it excludes Pluto,
the object a resemblance to which defines the class itself. The
suffix indicates a similarity to something else. Pluto does not
"resemble" Pluto -- it IS Pluto. Stars are not asteroids, for
example, in case you need an example.

    Moreover, it not clear why objects that actually DO resemble
Pluto should be called by an "-oid" suffix. This problem arises
because an "-oid" class is composed of many essentially
dissimilar objects that share only their superficial appearance
to, or a single characteristic with, the out-of-class object for
which they are named.

    Or if that single defining characteristic is the essential
one, what is the defining characteristic of the Plutoids? Well,
there's one ONE characteristic: iot is merely that they are
"Out There"! (And round and sun-orbiting.)

    Resolution 6A (2006): "Pluto is a "dwarf planet" by
the above definition and is recognized as the prototype
of a new category of trans-Neptunian objects," or so
the IAU website says, assuming that all TNO's are "like"
Pluto. I guess they know a lot more about Pluto -- and
the other TNO's! -- than we do, don't they?

    They voted, by the way, to name that common class
"plutons" to the delight of geologists everywhere. That
name is still on the IAU website.
http://www.iau.org/public_press/news/release/iau0601/

    Is "Plutoid" intended as a substitute for "Pluton"? I
guess so. Plutino is already taken; sorry! "Plutonian" has
been around for decades, but neither the geologists nor the
Gods of the Underworld would be happy with that choice.
"Plutan" sounds funny. "Plutoan" sounds Polynesian.

    Somehow, I doubt the IAU was aware of the complexities
of an "-oid" class. I think they wanted to to lump the Outer
Solar System together into a single-class group and dump it,
get it out of planetary astronomy, to make it irrelevant and
unimportant, and to get it out of the way.

    Let's look at the rest of that definition: "Plutoids are
celestial bodies in orbit around the sun at a distance greater
than that of Neptune..." This is what Space.com say is "the
official new definition," putting it in quotes. It is in fact
what IAU says in their own press release, proving that their
press officers are at least as incompetent as all other press
officers in the known Universe.

    OK. It will no doubt come as a great surprise to the Executive
Committee of the IAU (henceforth referred to as "Executoids")
that Pluto is NOT "in orbit around the sun at a distance greater
than that of Neptune" for 8% of its orbital period. This actually
does not matter as Pluto can't be a Plutoid at all as explained
above, but if it WAS a Plutoid, it would only BE one 92% of
the time, like a quantum virtual particle popping in and out.

    However, we can blame THIS mess on the Press, the IAU
included, because the actual qualifications for a "Plutoid" are
NOT those given in the news story! (As usual.) Fiurther
down, in the fine priont, here's what the IAU actually says:

    "..it was decided that, for naming purposes, any Solar System
body having (a) a semimajor axis greater than that of Neptune,
and (b) an absolute magnitude brighter than H = +1 magnitude
will be considered to be a plutoid, and be named by the WGPSN
and the CSBN. Name(s) proposed by the discovery team(s) will
be given deference. If further investigations show that the object
is not massive enough and does not qualify as a plutoid, it will
keep its name but change category."
http://www.iau.org/public_press/news/release/iau0804/

    The Devil is in the details, ALWAYS. Define things as you
want, it's the RULES that decide. With these rules, there will
NEVER be any other dwarf planets, no matter what (maybe).

    Why do I say that? Here's the deal. Mike Brown doesn't
get to be a planet-finder for finding the planet Eris, but he gets
two dwarf planets aznd a bag of marshmallows. Lowell
Observatory (Pluto's "owner") loses old Pluto's planethood,
but there will never be any other rivals called "planets." Christy,
the discoverer of half of a double planet gets nothing -- zip,
zilch, nada.

    It's that detail: a new candidate will have to have an absolute
magnitude (H) greater than +1.0. This purely arbitrary H = +1.0
cutoff eliminates all the other candidates because that value is
set 'way too high.

    And they are all too distant for anyone to determine that they
are round! Of course, most of them are, but you won't be able
to prove it for another generation... or two... or five.

    This means that "Easterbunny" IS a dwarf planet
(H = -0.48) and a "Plutoid". Congratulations, Easterbunny!
http://en.wikipedia.org/wiki/%28136472%29_2005_FY9

But the bigger, more massive and impressive "Santa" is
not (H = +0.17):
http://en.wikipedia.org/wiki/%28136108%29_2003_EL61
and neither is Sedna nor Ouaoar nor Orcus nor Ixion nor
Varuna nor (55565) 2002 AW197 nor (84522) 2002 TC302,
all larger than Ceres and all most likely round as a beach ball..
because none of these eight (dwarf) planets have got the H!

    Heck! Ceres doesn't have the H! Clearly beach-ball-like,
its albedo is the same as the average TNO and its H is +3.36,
less than all the eight PLANETS listed above... It's just damn
lucky it was already discovered because it would never make
it past the IAU today. Why would they not set the "H limit"
at +3.36, as planetary evidence of a ROUND ice-rock world
would suggest? Well...

    You can get rid of a helluva lot of planets that way! (It's a
clever move...) It also reduces the number of dwarf planets
to four (of which only three are officially recognized), so
eventually all this planet furor will die down. They will have
gotten rid of Pluto and nobody is going to remember all that
stuff about laughing-stock "dwarf" planets.

    The committee is essentially gambling that all brightest
objects have been discovered and is getting ready to fold
their cards and let dwarf planets become a footnote, having
dumped Pluto, which was what they wanted to do all along.

    And I've decided to go along with their definition...

    Is this the time and place to point out that under the 2006 IAU
definition of "planet," there are ONLY TWO planets in the Solar
System? They are Mercury and Venus, of course.

    The 2006 IAU definition has three requirements for Planethood,
one of which is that planets have cleared their own orbit and the
neighborhood around their orbit of all other objects, at least
those big enough to notice.

    Earth, Mars, Jupiter, Saturn, Uranus, and Neptune have all
permitted the continuing residence of a variety of rock balls,
ice balls, and other celestial trash very close to, actually
entwining with, their orbits, objects constantly flirting around
their respective barycenters like ants at a picnic, utterly failing
the strict requirements of Uruguayan Absolutism. These bodies
have NOT "cleared" their orbits. Those six bodies -- Earth,
Mars, Jupiter, Saturn, Uranus, and Neptune -- are all, by the
2006 IAU definition, "dwarf planets."

    I know you're all familiar with the Dwarf Planet Jupiter and
the Dwarf Planet Saturn with those cute little dwarf planet rings,
and so forth.

    If you're going to have a written definition of "planet" with
precise physical characteristics enumerated, rather than continue
with the historical usages, then I, for one, will adhere to it AS
WRITTEN.

    There is a sense in which the use of  the "-oid" suffix IS
appropriate. That is in the sense that the resemblance referred
to is inaccurate or inappropriate. Apes at a distance resemble
men ("anthropos"), hence anthropoid. A small solar system
body seen at a distance with the naked eye or small telescope
resembles a star ("aster"), hence asteroid (coined by Sir
William Herschel in 1801 when he looked at Ceres and saw
a point of light like a star). In other words, the "-oid" term
refers to resemblances based on ignorance.

    The IAU would seem to be the authority there.

    Now, I'm going to sit down and drink a toast to each and
every one of the Solar System's 23 Planets.



Sterling K. Webb
---------------------------------------------------------------------------
PS: Oddly, Mike Brown seems to think "Santa" (2003 EL61)
will be counted as a "Plutoid" even it clearly is not bright enough
(at H = +0.17); the IAU specifically says the H = +1.0 limit
applies. I don't why he thinks that. He discusses the magnitude
limit, says he finds it strange. I don't think he's figured it out yet.
http://www.mikebrownsplanets.com/2008/06/plutoid-fever.html
--------------------------------------------------------------------------------
----- Original Message ----- 
From: <lebofsky at lpl.arizona.edu>
To: <cynapse at charter.net>
Cc: <meteorite-list at meteoritecentral.com>
Sent: Wednesday, June 11, 2008 3:10 PM
Subject: Re: [meteorite-list] And the winner is-- Plutoid!


Hi All:

I will probably be going to the August meeting in Maryland, so it will be
interesting to see how this new terminology goes over.

So everything round and icy (maybe) is a Plutoid, which means Pluto-like.
Since we don't know what Pluto is (at least what to define it as), this
really makes a whole lot of sense. NOT!

I predict it will go over like a lead balloon.

Larry L.

The previous statements are the opinion of the author and may not reflect
the opinions of other scientists.



On Wed, June 11, 2008 12:58 pm, Darren Garrison wrote:
> http://www.space.com/scienceastronomy/080611-plutoid-planets.html
>
>
> Pluto Now Called a Plutoid
> By Robert Roy Britt
> Senior Science Writer
> posted: 11 June 2008
> 10:30 am ET
>
>
> Updated 2:00 p.m. ET
>
>
> Pluto's years-long identity crisis just got more complex today.
>
>
> The International Astronomical Union has decided on the term "plutoid" as
> a name for Pluto and other objects that just two years ago were redefined
> as "dwarf planets."
>
> The surprise decision is unlikely to stem ongoing controversy and
> confusion, astronomers say.
>
> Sidestepping concerns of many astronomers worldwide, the IAU's decision,
> at a meeting of its Executive Committee in Oslo, comes almost two years
> after it stripped Pluto of its planethood and introduced the term "dwarf
> planets" for Pluto and other small round objects that often travel highly
> elliptical paths around the sun in the far reaches of the solar system.
>
> "Most of the people in astronomy and planetary science community had no
> idea this was going to come out," said Hal Weaver of the Johns Hopkins
> University
> Applied Physics Laboratory. Weaver called the new definition "sort of
> outdated, outmoded, archaic."
>
> A meeting in August at the Applied Physics Laboratory is slated to debate
> the entire topic of defining planets. Meanwhile, other astronomers said
> the new definition needed more definition or that it might simply not be
> used.
>
> "This seems like an unattractive term and an unnecessary one to me," said
> David
> Morrison, an astronomer at NASA's Ames Research Center who, in 2006, said
> the IAU's actions on Pluto have created major rifts among astronomers.
>
>
> The new definition
>
>
> The name plutoid was proposed by the members of the IAU Committee on
> Small Body
> Nomenclature (CSBN), accepted by the Board of Division III and by the IAU
> Working Group for Planetary System Nomenclature (WGPSN), and approved by
> the IAU Executive Committee at its recent meeting in Oslo, according to a
> statement released today.
>
> Here's the official new definition:
>
>
> "Plutoids are celestial bodies in orbit around the sun at a distance
> greater than that of Neptune that have sufficient mass for their
> self-gravity to overcome rigid body forces so that they assume a
> hydrostatic equilibrium (near-spherical) shape, and that have not cleared
> the neighborhood around their orbit."
>
> In short: small round things beyond Neptune that orbit the sun and have
> lots of rocky neighbors.
>
> The two known and named plutoids are Pluto and Eris, the IAU stated. The
> organization expects more plutoids will be found.
>
> "Rather than resistance to 'plutoid,' I think we'll just be hearing
> groans," said Stephen J. Kortenkamp, senior scientist at the Planetary
> Science Institute
> in Tucson.
>
> Controversy continues
>
>
> One IAU leader recognizes it is adding to an ongoing controversy.
>
>
> The IAU has been responsible for naming planetary bodies and their
> satellites since the early 1900s. Its decision in 2006 to demote Pluto was
> highly controversial, with some astronomers saying simply that they would
> not heed it and questioning the IAU's validity as a governing body.
>
> "The IAU is a democratic organization, thus open to comments and
> criticism of any kind," IAU General Secretary Karel A. van der Hucht told
> SPACE.com by email
> today. "Given the history of the issue, we will probably never reach a
> complete consensus."
>
> Van der Hucht said the new designation is not a further demotion for the
> once-favorite planet of grade-school children: "Pluto is now the prototype
> of a very interesting category of outer solar system bodies."
>
> IAU Division III President Edward L.G. Bowell of the Lowell Observatory
> said the ruling stems from unfinished business from the forging of a
> planet definition in 2006. Bowell said there is no agreed-upon way to
> define "dwarf planet" yet, so "officers of the IAU thought it would be a
> good idea to adopt alternative criteria that would at least allow those
> large bodies to be named as though they were dwarf planets."
>
> It remains to be seen whether astronomers will use the new term.
>
>
> "My guess is that no one is going to much use this term, though perhaps
> I'm
> wrong," said Caltech astronomer Mike Brown, who has led the discovery of
> several objects in the outer solar system, including Eris. "But I don't
> think that this will be because it is controversial, just not particularly
> necessary."
>
> Brown was unaware of the new definition until the IAU announced it today.
>
>
> "Back when the term 'pluton' was nixed they said they would come up with
> another one," Brown said. "So I guess they finally did."
>
> Reactions were not all negative, however.
>
>
> "It seems like a reasonable decision to me, and given the excitement
> generated by New Horizons [a NASA probe headed for Pluto], it's in
> everyone's interest to favor the largest Kuiper belt objects with their
> own categorical designation," said Gregory Laughlin, a University of
> California, Santa Cruz extrasolar planet
> researcher.
>
> "The only fly in the ointment that I can envision is if a plutoid larger,
> than, say, Mars is detected," Laughlin points out. "In that case, I think
> we'd see a big flare-up of the what-is-a-planet debate."
>
> More debate coming
>
>
> The dwarf planet Ceres (which used to be called an asteroid, and before
> that was called a planet!) is not a plutoid as it is located in the
> asteroid belt between Mars and Jupiter, according to the IAU. Current
> scientific knowledge lends credence to the belief that Ceres is the only
> object of its kind, the IAU stated. Therefore, a separate category of
> Ceres-like dwarf planets will not be
> proposed at this time, the reasoning goes.
>
> Weaver, the Johns Hopkins researcher, has helped organized a meeting,
> planned earlier this year for Aug. 14-16 at Johns Hopkins University
> Applied Physics
> Laboratory, that aims to bring astronomers of varying viewpoints together
> to discuss the controversy.
>
> "We're not trying to slam the IAU, it's just that we also don't want to
> lead people to the idea that there's a handful of people who decide where
> science should go," Weaver said today. The meeting is designed to "address
> this question in terms of a scientific conference." He said no votes will
> be taken at the meeting. Rather, it's a time to "sit back and take stock
> of everything we've learned in the past couple of decades."
>
> The term plutoid joins a host of other odd words -- plutinos, centaurs,
> cubewanos and EKOs -- that astronomers have conjured in recent years to
> define objects in the outer solar system, whose appearance seems to grow
> more complex every year.
>
> Kortenkamp wonders if "plutoid" isn't just one more confusing term in the
> cosmic lexicon.
>
> "So Pluto is a Kuiper belt object, a plutino (the unofficial but nearly
> universally accepted name for objects in the 2:3 resonance with Neptune),
> a dwarf planet, and now also a plutoid?" he said. "If the IAU is trying to
> make things more clear, I think it needs to try again. This is just
> another layer of confusion that will feed the "pluto is a planet" camp at
> the [Johns Hopkings] meeting."
>
> Kortenkamp also thinks the new defiinition leaves Ceres up in the air:
> "And this
> "-oid" classification doesn't apply to Ceres?" he asks. "Okay, so does
> that means we continue calling Ceres an ASTERoid?"
>
> Asked if Ceres remains a dwarf planet and is not an asteroid, Bowell, the
> IAU
> official, said: "I think so!"
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