IAU updates scientific definition of planet to match current knowledge

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Date: 25 Aug 2006 12:32:25
From: canopus56
Subject: IAU updates scientific definition of planet to match current knowledge

I posted this because I had to see at least one thread header in this
newsgroup that states what the IAU did in the positive light that it
intended, instead of the negative media spin of the "IAU dumped Pluto."
That postive light was, to quote the preamble of the resolution
(appended): "Contemporary observations are changing our understanding
of planetary systems, and it is important that our nomenclature for
objects reflect our current understanding."

Among the things that science should do is (1) accrue new knowledge and
advance our understanding of the natural world, and (2) husband the
general public's conventional wisdom about the natural world.

The story is not the "IAU made the general public and school children
feel uncomfortable by changing the definition of planet and demoting
Pluto as a planet." The story is: "members of the IAU advanced our
knowledge and understanding of the structure of the solar system. Based
on more observations with new satellites and better telescopes over the
last 70 years, scientific terminology to describe our better
understanding of solar system structure is being improved to match this
improved understanding."

Science should not bow to popular linguistic whims of the general
public. What will be next? Something like: "We need to keep the
definition of 'evolution' within 'safe' boundaries, so we don't upset
the children and inconvenience textbook manufacturers."

The best gift that we can give to subsequent generations is an expanded
view of the natural world with an improved depth of understanding of
how the natural world works. To do otherwise is a disservice to the
next generation, regardless of whatever transient inconvenience it may
cause to them, to textbook manufacturers, to the builders of
planetarium displays, or to our own natural human desire to feel secure
in an familiar and stable view of the world around us.

Clyde Tombaugh is probably spinning in his grave on this, but not
because Pluto was demoted. He would be spinning in his grave because
retaining Pluto as a planet is - based on our improvements in our
understanding the solar system's structure over the last 70 years - bad
science. Tombaugh spent all those hours at the blink comparator in
order to advance our knowledge of the solar system. 70 years later his
efforts bore significant fruit, no doubt in part through the many
future astronomers that he inspired while teaching at New Mexico State
University from the 1950s to the 1970s.

I never met him or heard him lecture, but if alive today, he would
probably be dismayed at an attempt to cling to an outdated model of our
solar system. If alive today, rather than hand-wringing over the loss
of "his planet," Tombaugh would probably be expending his engergies to
get a peak into the eyepiece that Mike Brown (co-discover of 2003UB313)
is looking through.

Science marches on and I, for one, gladly will march with it.

- Canopus56

-----------------------

http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html

RESOLUTIONS

Resolution 5A is the principal definition for the IAU usage of "planet"
and related terms.

Resolution 6A creates for IAU usage a new class of objects, for which
Pluto is the prototype. The IAU will set up a process to name these
objects.

IAU Resolution: Definition of a Planet in the Solar System
Contemporary observations are changing our understanding of planetary
systems, and it is important that our nomenclature for objects reflect
our current understanding. This applies, in particular, to the
designation 'planets'. The word 'planet' originally described
'wanderers' that were known only as moving lights in the sky. Recent
discoveries lead us to create a new definition, which we can make using
currently available scientific information.

RESOLUTION 5A
The IAU therefore resolves that "planets" and other bodies in our Solar
System be defined into three distinct categories in the following way:

(1) A "planet"1 is a celestial body that (a) is in orbit around the
Sun, (b) has sufficient mass for its self-gravity to overcome rigid
body forces so that it assumes a hydrostatic equilibrium (nearly round)
shape, and (c) has cleared the neighbourhood around its orbit.

(2) A "dwarf planet" is a celestial body that (a) is in orbit around
the Sun, (b) has sufficient mass for its self-gravity to overcome rigid
body forces so that it assumes a hydrostatic equilibrium (nearly round)
shape2 , (c) has not cleared the neighbourhood around its orbit, and
(d) is not a satellite.

(3) All other objects3 except satellites orbiting the Sun shall be
referred to collectively as "Small Solar-System Bodies".

---------------------------------------------------------------------------=
=AD-----

1 The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, and Neptune.

2 An IAU process will be established to assign borderline objects into
either dwarf planet and other categories.

3 These currently include most of the Solar System asteroids, most
Trans-Neptunian Objects (TNOs), comets, and other small bodies.

---------------------------------------------------------------------------=
=AD-----

IAU Resolution: Pluto

RESOLUTION 6A
The IAU further resolves:

Pluto is a "dwarf planet" by the above definition and is recognized as
the prototype of a new category of trans-Neptunian objects.1

Date: 25 Aug 2006 15:18:45
From: Ed
Subject: Re: IAU updates scientific definition of planet to match current knowledge

Tyranny of the Minority at the IAU meeting.

Date: 25 Aug 2006 15:14:39
From: Ed
Subject: Re: IAU updates scientific definition of planet to match current knowledge

Oh, I forgot you are always right and never wrong!

Date: 25 Aug 2006 13:57:09
From: Don't Be Evil
Subject: Re: IAU updates scientific definition of planet to match current knowledge

canopus56 wrote:
> I posted this because I had to see at least one thread header in this
> newsgroup that states what the IAU did in the positive light that it
> intended, instead of the negative media spin of the "IAU dumped Pluto."
> That postive light was, to quote the preamble of the resolution
> (appended): "Contemporary observations are changing our understanding
> of planetary systems, and it is important that our nomenclature for
> objects reflect our current understanding."
>
> Among the things that science should do is (1) accrue new knowledge and
> advance our understanding of the natural world, and (2) husband the
> general public's conventional wisdom about the natural world.
>
> The story is not the "IAU made the general public and school children
> feel uncomfortable by changing the definition of planet and demoting
> Pluto as a planet." The story is: "members of the IAU advanced our
> knowledge and understanding of the structure of the solar system. Based
> on more observations with new satellites and better telescopes over the
> last 70 years, scientific terminology to describe our better
> understanding of solar system structure is being improved to match this
> improved understanding."
>
> Science should not bow to popular linguistic whims of the general
> public. What will be next? Something like: "We need to keep the
> definition of 'evolution' within 'safe' boundaries, so we don't upset
> the children and inconvenience textbook manufacturers."
>
> The best gift that we can give to subsequent generations is an expanded
> view of the natural world with an improved depth of understanding of
> how the natural world works. To do otherwise is a disservice to the
> next generation, regardless of whatever transient inconvenience it may
> cause to them, to textbook manufacturers, to the builders of
> planetarium displays, or to our own natural human desire to feel secure
> in an familiar and stable view of the world around us.
>
> Clyde Tombaugh is probably spinning in his grave on this, but not
> because Pluto was demoted. He would be spinning in his grave because
> retaining Pluto as a planet is - based on our improvements in our
> understanding the solar system's structure over the last 70 years - bad
> science. Tombaugh spent all those hours at the blink comparator in
> order to advance our knowledge of the solar system. 70 years later his
> efforts bore significant fruit, no doubt in part through the many
> future astronomers that he inspired while teaching at New Mexico State
> University from the 1950s to the 1970s.
>
> I never met him or heard him lecture, but if alive today, he would
> probably be dismayed at an attempt to cling to an outdated model of our
> solar system. If alive today, rather than hand-wringing over the loss
> of "his planet," Tombaugh would probably be expending his engergies to
> get a peak into the eyepiece that Mike Brown (co-discover of 2003UB313)
> is looking through.
>
> Science marches on and I, for one, gladly will march with it.
>
> - Canopus56
>
> -----------------------
>
> http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html
>
> RESOLUTIONS
>
> Resolution 5A is the principal definition for the IAU usage of "planet"
> and related terms.
>
> Resolution 6A creates for IAU usage a new class of objects, for which
> Pluto is the prototype. The IAU will set up a process to name these
> objects.
>
> IAU Resolution: Definition of a Planet in the Solar System
> Contemporary observations are changing our understanding of planetary
> systems, and it is important that our nomenclature for objects reflect
> our current understanding. This applies, in particular, to the
> designation 'planets'. The word 'planet' originally described
> 'wanderers' that were known only as moving lights in the sky. Recent
> discoveries lead us to create a new definition, which we can make using
> currently available scientific information.
>
> RESOLUTION 5A
> The IAU therefore resolves that "planets" and other bodies in our Solar
> System be defined into three distinct categories in the following way:
>
> (1) A "planet"1 is a celestial body that (a) is in orbit around the
> Sun, (b) has sufficient mass for its self-gravity to overcome rigid
> body forces so that it assumes a hydrostatic equilibrium (nearly round)
> shape, and (c) has cleared the neighbourhood around its orbit.
>
> (2) A "dwarf planet" is a celestial body that (a) is in orbit around
> the Sun, (b) has sufficient mass for its self-gravity to overcome rigid
> body forces so that it assumes a hydrostatic equilibrium (nearly round)
> shape2 , (c) has not cleared the neighbourhood around its orbit, and
> (d) is not a satellite.
>
> (3) All other objects3 except satellites orbiting the Sun shall be
> referred to collectively as "Small Solar-System Bodies".
>
> -------------------------------------------------------------------------=
--=AD-----
>
>
>
> 1 The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn,
> Uranus, and Neptune.
>
> 2 An IAU process will be established to assign borderline objects into
> either dwarf planet and other categories.
>
> 3 These currently include most of the Solar System asteroids, most
> Trans-Neptunian Objects (TNOs), comets, and other small bodies.
>
> -------------------------------------------------------------------------=
--=AD-----
>
>
> IAU Resolution: Pluto
>
> RESOLUTION 6A
> The IAU further resolves:
>
> Pluto is a "dwarf planet" by the above definition and is recognized as
> the prototype of a new category of trans-Neptunian objects.

Very well put. Mike Brown happily gave up 15 potential planets with
the rejection of last week's proposal.

I'd respond to "They took Pluto away!" with "No they didn't, they added
the rest of the Kuiper Belt."

Date: 25 Aug 2006 14:54:03
From: Brian Tung
Subject: Re: IAU updates scientific definition of planet to match current knowledge

Don't Be Evil wrote:
> I'd respond to "They took Pluto away!" with "No they didn't, they added
> the rest of the Kuiper Belt."

Sounds like a wedding blessing. "You're not losing a planet, you're
gaining a plutino (or several dozen)."

--
Brian Tung <brian@isi.edu >
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html

Date: 25 Aug 2006 13:26:24
From: Ed
Subject: Re: IAU updates scientific definition of planet to match current knowledge

Not so fast....

You mean you didn't get the memo?

This isn't finished yet by a long shot.

There are about 10,000 or so professional astronomers
and only 370 voted on the resolution (according to Phil Plait aka "The
Bad Astronomer"
187 for to 183 against.

So you are telling me that 5 people have the right to demote Pluto or
to decide any other thing for the rest of humanity? Egads, girl, please
get a life. How would you like 5 strangers to tell you what to do? I
sure wouldn't.

This is not over according to Dr. Alan Stern, chief scientist of the
New Horizon's Pluto Mission. He is already working on a petition to
overturn the ruling. And as a Co-Coordinator of the JPL/NASA Night Sky
Network for BMAA., Inc. I have already asked if
Night Sky wants to circulate a petition of support for this effort
among other Night Sky members.

Touche!

Date: 26 Aug 2006 00:08:19
From: Terry B
Subject: Re: IAU updates scientific definition of planet to match current knowledge

"Ed" <ed1ward2@verizon.net > wrote in message
news:1156537582.743455.143680@m73g2000cwd.googlegroups.com...
>
> Not so fast....
>
> You mean you didn't get the memo?
>
> This isn't finished yet by a long shot.
>
> There are about 10,000 or so professional astronomers
> and only 370 voted on the resolution (according to Phil Plait aka "The
> Bad Astronomer"
> 187 for to 183 against.
>
Isn't this the democratic system that the US is fighting for?
How many more people voted for your president than against him?

Terry B

Date: 25 Aug 2006 14:42:17
From: Greg Crinklaw
Subject: Re: IAU updates scientific definition of planet to match current

Ed wrote:
> Not so fast....

I thought what he wrote was positive and inspiring. Your continued
diatribes seem rather petty in comparison. Why not let it rest?

Talk about minorities making decisions... it is your point of view that
is the real minority, no matter how loudly you proclaim otherwise.

--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)

SkyTools: http://www.skyhound.com/cs.html
Observing: http://www.skyhound.com/sh/skyhound.html
Comets: http://www.skyhound.com/sh/comets.html

To reply take out your eye

Date: 25 Aug 2006 13:24:11
From: oriel36
Subject: Re: IAU updates scientific definition of planet to match current knowledge

The Earth's deviation from a perfect sphere is due to rotational
dynamics of the molten/flexible interior,it means that it is a
continuing dynamic influencing planetary structure and especially the
motion of the surface fractured crust.

The sudden meaningless fuss over definitions is fine,perhaps they
should define an 'astronomer ' first before they tackle celestial
structures.It is the presence of the rare type of astronomer that is
needed to restore a balance when the discipline is dominated by silly
cosmologists and astrophotographers -

"To set down in books the apparent paths of the planets [viasplanetarum
apparentes] and the record of their motions is especially the task of
the practical and mechanical part of astronomy; to discover their true
and genuine path [vias vero veras et genuinas] is . . .the task of
contemplative astronomy; while to say by what circle and lines correct
images of those true motions may be depicted on paper is the concern of
the inferior tribunal of geometers" Kepler

When Kepler wrote that there were no celestial sphere geometers
justifying the Ra/Dec system so things are presently at a nadir.

canopus56 wrote:

> I posted this because I had to see at least one thread header in this
> newsgroup that states what the IAU did in the positive light that it
> intended, instead of the negative media spin of the "IAU dumped Pluto."
> That postive light was, to quote the preamble of the resolution
> (appended): "Contemporary observations are changing our understanding
> of planetary systems, and it is important that our nomenclature for
> objects reflect our current understanding."
>
> Among the things that science should do is (1) accrue new knowledge and
> advance our understanding of the natural world, and (2) husband the
> general public's conventional wisdom about the natural world.
>
> The story is not the "IAU made the general public and school children
> feel uncomfortable by changing the definition of planet and demoting
> Pluto as a planet." The story is: "members of the IAU advanced our
> knowledge and understanding of the structure of the solar system. Based
> on more observations with new satellites and better telescopes over the
> last 70 years, scientific terminology to describe our better
> understanding of solar system structure is being improved to match this
> improved understanding."
>
> Science should not bow to popular linguistic whims of the general
> public. What will be next? Something like: "We need to keep the
> definition of 'evolution' within 'safe' boundaries, so we don't upset
> the children and inconvenience textbook manufacturers."
>
> The best gift that we can give to subsequent generations is an expanded
> view of the natural world with an improved depth of understanding of
> how the natural world works. To do otherwise is a disservice to the
> next generation, regardless of whatever transient inconvenience it may
> cause to them, to textbook manufacturers, to the builders of
> planetarium displays, or to our own natural human desire to feel secure
> in an familiar and stable view of the world around us.
>
> Clyde Tombaugh is probably spinning in his grave on this, but not
> because Pluto was demoted. He would be spinning in his grave because
> retaining Pluto as a planet is - based on our improvements in our
> understanding the solar system's structure over the last 70 years - bad
> science. Tombaugh spent all those hours at the blink comparator in
> order to advance our knowledge of the solar system. 70 years later his
> efforts bore significant fruit, no doubt in part through the many
> future astronomers that he inspired while teaching at New Mexico State
> University from the 1950s to the 1970s.
>
> I never met him or heard him lecture, but if alive today, he would
> probably be dismayed at an attempt to cling to an outdated model of our
> solar system. If alive today, rather than hand-wringing over the loss
> of "his planet," Tombaugh would probably be expending his engergies to
> get a peak into the eyepiece that Mike Brown (co-discover of 2003UB313)
> is looking through.
>
> Science marches on and I, for one, gladly will march with it.
>
> - Canopus56
>
> -----------------------
>
> http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html
>
> RESOLUTIONS
>
> Resolution 5A is the principal definition for the IAU usage of "planet"
> and related terms.
>
> Resolution 6A creates for IAU usage a new class of objects, for which
> Pluto is the prototype. The IAU will set up a process to name these
> objects.
>
> IAU Resolution: Definition of a Planet in the Solar System
> Contemporary observations are changing our understanding of planetary
> systems, and it is important that our nomenclature for objects reflect
> our current understanding. This applies, in particular, to the
> designation 'planets'. The word 'planet' originally described
> 'wanderers' that were known only as moving lights in the sky. Recent
> discoveries lead us to create a new definition, which we can make using
> currently available scientific information.
>
> RESOLUTION 5A
> The IAU therefore resolves that "planets" and other bodies in our Solar
> System be defined into three distinct categories in the following way:
>
> (1) A "planet"1 is a celestial body that (a) is in orbit around the
> Sun, (b) has sufficient mass for its self-gravity to overcome rigid
> body forces so that it assumes a hydrostatic equilibrium (nearly round)
> shape, and (c) has cleared the neighbourhood around its orbit.
>
> (2) A "dwarf planet" is a celestial body that (a) is in orbit around
> the Sun, (b) has sufficient mass for its self-gravity to overcome rigid
> body forces so that it assumes a hydrostatic equilibrium (nearly round)
> shape2 , (c) has not cleared the neighbourhood around its orbit, and
> (d) is not a satellite.
>
> (3) All other objects3 except satellites orbiting the Sun shall be
> referred to collectively as "Small Solar-System Bodies".
>
> -------------------------------------------------------------------------=
--=AD-----
>
>
>
> 1 The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn,
> Uranus, and Neptune.
>
> 2 An IAU process will be established to assign borderline objects into
> either dwarf planet and other categories.
>
> 3 These currently include most of the Solar System asteroids, most
> Trans-Neptunian Objects (TNOs), comets, and other small bodies.
>
> -------------------------------------------------------------------------=
--=AD-----
>
>
> IAU Resolution: Pluto
>
> RESOLUTION 6A
> The IAU further resolves:
>
> Pluto is a "dwarf planet" by the above definition and is recognized as
> the prototype of a new category of trans-Neptunian objects.1

Date: 25 Aug 2006 12:45:48
From: atasselli@hotmail.com
Subject: Re: IAU updates scientific definition of planet to match current knowledge

Date: 25 Aug 2006 23:38:49
From: canopus56
Subject: Re: IAU updates scientific definition of planet to match current knowledge

Ed wrote:
> There are about 10,000 or so professional astronomers
> and only 370 voted on the resolution . . . 187 for to 183 against.

Your assumption is that the science should be conducted as a democracy
- as distinguished from an atmosphere or process of free inquiry.

In science, unlike the political process, proposals (hypotheses) are
first judged by their inherent strength - their ability to explain
observed facts in nature - independent of their proponent. A small
minority of inherently uncertain matters may need to be given
provisional definitions based on a consenus vote, but this rare.

> I have already asked if Night Sky wants to circulate a petition of support
> for this effort among other Night Sky members.

Before you conclude that the result of the IAU vote is improper and
needs to be revisited, I ask you this:

What definition best explains the our current knowledge of the physical
structure of the solar system: the classical definition or IAU
resolutions 5A and 6A?

Granted the resolution 5A definition does appear to an ambiguity that
you have focused on - the phrase "has cleared the neighbourhood around
its orbit," but this can fixed by further amendment.

Brian Tung, in another thread, I believe refered you to Steven Soter's
"What is a Planet?"
article:

http://arxiv.org/ftp/astro-ph/papers/0608/0608359.pdf

Regardless of whether the IAU actually discussed Soter's paper, his
reasoning for the "clearing" criteria seems sound. As shown in his
Figure 3, there is a clear physical gap for the "clearing" of orbits
for the eight planets not seen for trans-neptunian objects (TNOs) -
that is inherently related to the nature of the eight planets.

"Clearing" in Soter's use of the term does not mean a complete vacuming
of an orbit or all matter. Thousands of small meteorites and some
asteriods remain. For example, in the "clearing" of the Earth's orbit,
10^-6 of Earth's mass (0.000001) remains in rubble and small bodies in
Earth's orbit. In the case of Pluto, a much for massive ratio of
rubble to pluton exists - 10^-1/2 or 0.32 or 32% - is estimated to
remain in Pluto's orbit.

"Clearing" in Soter's sense is compatible with the quote of Alan Stern,
of NASA's Pluto Mission, attributed to him in another thread: "But Dr
Stern pointed out that Earth, Mars, Jupiter and Neptune have also not
fully cleared their orbital zones. Earth orbits with 10,000 near-Earth
asteroids. Jupiter, meanwhile, is accompanied by 100,000 Trojan
asteroids on its orbital path."

Resolution 5A and 6A are an advance in the definition of the term
"planet" over the classical or original IAU resolution because:

a) it better harmonizes our current knowledge of TNOs, the Kupier Belt
and the Oort cloud relative to the "inner" solar system;

b) it is a classification that is based on defensible physical
characteristics of traditional 8 planets vs. other cateogries of
objects.

If you feel that Resolutions 5A and 6A are not an improvement over the
classical definition or the initial IAU resolution, than what facts
support your claim of the superiority of either of those alternative
defintions?

Let set aside for the moment your concern of the fairness of the IAU
process - which is a distinctly different question of the scientific
merit of the definition.

Please, review Soter's paper and his Figure 3, before you respond.

- Canopus56

Date: 27 Aug 2006 02:10:48
From: Wally Wonderful
Subject: Re: IAU updates scientific definition of planet to match current

canopus56 wrote:

> I posted this because I had to see at least one thread header in this
> newsgroup that states what the IAU did in the positive light that it
> intended, instead of the negative media spin of the "IAU dumped Pluto."
> That postive light was, to quote the preamble of the resolution
> (appended): "Contemporary observations are changing our understanding
> of planetary systems, and it is important that our nomenclature for
> objects reflect our current understanding."
>
> Among the things that science should do is (1) accrue new knowledge and
> advance our understanding of the natural world, and (2) husband the
> general public's conventional wisdom about the natural world.
>
> The story is not the "IAU made the general public and school children
> feel uncomfortable by changing the definition of planet and demoting
> Pluto as a planet." The story is: "members of the IAU advanced our
> knowledge and understanding of the structure of the solar system. Based
> on more observations with new satellites and better telescopes over the
> last 70 years, scientific terminology to describe our better
> understanding of solar system structure is being improved to match this
> improved understanding."
>
> Science should not bow to popular linguistic whims of the general
> public. What will be next? Something like: "We need to keep the
> definition of 'evolution' within 'safe' boundaries, so we don't upset
> the children and inconvenience textbook manufacturers."
>
> The best gift that we can give to subsequent generations is an expanded
> view of the natural world with an improved depth of understanding of
> how the natural world works. To do otherwise is a disservice to the
> next generation, regardless of whatever transient inconvenience it may
> cause to them, to textbook manufacturers, to the builders of
> planetarium displays, or to our own natural human desire to feel secure
> in an familiar and stable view of the world around us.
>
> Clyde Tombaugh is probably spinning in his grave on this, but not
> because Pluto was demoted. He would be spinning in his grave because
> retaining Pluto as a planet is - based on our improvements in our
> understanding the solar system's structure over the last 70 years - bad
> science. Tombaugh spent all those hours at the blink comparator in
> order to advance our knowledge of the solar system. 70 years later his
> efforts bore significant fruit, no doubt in part through the many
> future astronomers that he inspired while teaching at New Mexico State
> University from the 1950s to the 1970s.
>
> I never met him or heard him lecture, but if alive today, he would
> probably be dismayed at an attempt to cling to an outdated model of our
> solar system. If alive today, rather than hand-wringing over the loss
> of "his planet," Tombaugh would probably be expending his engergies to
> get a peak into the eyepiece that Mike Brown (co-discover of 2003UB313)
> is looking through.
>
> Science marches on and I, for one, gladly will march with it.

I am resisting what I would like to say. One word would cover it. You did not
know Clyde Tombaugh but yet you know very much about him and what his
feelings would be! Pat your self .............. on the ass!
jw

>
>
> - Canopus56
>
> -----------------------
>
> http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html
>
> RESOLUTIONS
>
> Resolution 5A is the principal definition for the IAU usage of "planet"
> and related terms.
>
> Resolution 6A creates for IAU usage a new class of objects, for which
> Pluto is the prototype. The IAU will set up a process to name these
> objects.
>
> IAU Resolution: Definition of a Planet in the Solar System
> Contemporary observations are changing our understanding of planetary
> systems, and it is important that our nomenclature for objects reflect
> our current understanding. This applies, in particular, to the
> designation 'planets'. The word 'planet' originally described
> 'wanderers' that were known only as moving lights in the sky. Recent
> discoveries lead us to create a new definition, which we can make using
> currently available scientific information.
>
> RESOLUTION 5A
> The IAU therefore resolves that "planets" and other bodies in our Solar
> System be defined into three distinct categories in the following way:
>
> (1) A "planet"1 is a celestial body that (a) is in orbit around the
> Sun, (b) has sufficient mass for its self-gravity to overcome rigid
> body forces so that it assumes a hydrostatic equilibrium (nearly round)
> shape, and (c) has cleared the neighbourhood around its orbit.
>
> (2) A "dwarf planet" is a celestial body that (a) is in orbit around
> the Sun, (b) has sufficient mass for its self-gravity to overcome rigid
> body forces so that it assumes a hydrostatic equilibrium (nearly round)
> shape2 , (c) has not cleared the neighbourhood around its orbit, and
> (d) is not a satellite.
>
> (3) All other objects3 except satellites orbiting the Sun shall be
> referred to collectively as "Small Solar-System Bodies".
>
> ---------------------------------------------------------------------------�-----
>
> 1 The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn,
> Uranus, and Neptune.
>
> 2 An IAU process will be established to assign borderline objects into
> either dwarf planet and other categories.
>
> 3 These currently include most of the Solar System asteroids, most
> Trans-Neptunian Objects (TNOs), comets, and other small bodies.
>
> ---------------------------------------------------------------------------�-----
>
> IAU Resolution: Pluto
>
> RESOLUTION 6A
> The IAU further resolves:
>
> Pluto is a "dwarf planet" by the above definition and is recognized as
> the prototype of a new category of trans-Neptunian objects.1