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Main Date: 16 Aug 2006 08:49:01 From: Subject: The IAU Draft Definition of 'Planet' and 'Plutons' http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_release.html The IAU draft definition of "planet" and "plutons" August 16, 2006 Prague The world's astronomers, under the auspices of the International Astronomical Union (IAU), have concluded two years of work defining the difference between "planets" and the smaller "solar system bodies" such as comets and asteroids. If the definition is approved by the astronomers gathered 14-25 August 2006 at the IAU General Assembly in Prague, our Solar System will include 12 planets, with more to come: eight classical planets that dominate the system, three planets in a new and growing category of "plutons" - Pluto-like objects - and Ceres. Pluto remains a planet and is the prototype for the new category of "plutons." With the advent of powerful new telescopes on the ground and in space, planetary astronomy has gone though an exciting development over the past decade. For thousands of years very little was known about the planets other than they were objects that moved in the sky with respect to the background of fixed stars. In fact the word "planet" comes from the Greek word for "wanderer". But today hosts of newly discovered large objects in the outer regions of our Solar System present a challenge to our historically based definition of a "planet". At first glance one should think that it is easy to define what a planet is - a large and round body. On second thought difficulties arise, as one could ask "where is the lower limit?" - how large, and how round should an asteroid be before it becomes a planet - as well as "where is the upper limit?" - how large can a planet be before it becomes a brown dwarf or a star? IAU President Ron Ekers explains the rational behind a planet definition: "Modern science provides much more knowledge than the simple fact that objects orbiting the Sun appear to move with respect to the background of fixed stars. For example, recent new discoveries have been made of objects in the outer regions of our Solar System that have sizes comparable to and larger than Pluto. These discoveries have rightfully called into question whether or not they should be considered as new 'planets.' " The International Astronomical Union has been the arbiter of planetary and satellite nomenclature since its inception in 1919. The world's astronomers, under the auspices of the IAU, have had official deliberations on a new definition for the word "planet" for nearly two years. IAU's top, the so-called Executive Committee, led by Ekers, formed a Planet Definition Committee (PDC) comprised by seven persons who were astronomers, writers, and historians with broad international representation. This group of seven convened in Paris in late June and 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." According to the new draft definition, two conditions must be satisfied for an object to be called a "planet." First, the object must be in orbit around a star, while not being itself a star. Second, the object must be large enough (or more technically correct, massive enough) for its own gravity to pull it into a nearly spherical shape. The shape of objects with mass above 5 x 1020 kg and diameter greater than 800 km would normally be determined by self-gravity, but all borderline cases would have to be established by observation. If the proposed Resolution is passed, the 12 planets in our Solar System will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313. The name 2003 UB313 is provisional, as a "real" name has not yet been assigned to this object. A decision and announcement of a new name are likely not to be made during the IAU General Assembly in Prague, but at a later time. The naming procedures depend on the outcome of the Resolution vote. There will most likely be more planets announced by the IAU in the future. Currently a dozen "candidate planets" are listed on IAU's "watchlist" which keeps changing as new objects are found and the physics of the existing candidates becomes better known. The IAU draft Resolution also defines a new category of planet for official use: "pluton". Plutons are distinguished from classical planets in that they reside in orbits around the Sun that take longer than 200 years to complete (i.e. they orbit beyond Neptune). Plutons typically have orbits that are highly tilted with respect to the classical planets (technically referred to as a large orbital inclination). Plutons also typically have orbits that are far from being perfectly circular (technically referred to as having a large orbital eccentricity). All of these distinguishing characteristics for plutons are scientifically interesting in that they suggest a different origin from the classical planets. The draft "Planet Definition" Resolution will be discussed and refined during the General Assembly and then it (plus four other Resolutions) will be presented for voting at the 2nd session of the GA 24 August between 14:00 and 17:30 CEST. Notes for editors The IAU is the international astronomical organisation that brings together distinguished astronomers from all nations of the world. IAU's mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Founded in 1919, the IAU is the world's largest professional body for astronomers. The IAU General Assembly is held every three years and is one of the largest and most diverse meetings in the astronomical community's calendar. Science contacts (the persons below can all be reached via the IAU GA Press Office, see bottom) Owen Gingerich IAU Planet Definition Committee Chair Tel: via the Press Room +420-261-177-075 Iwan Williams President, IAU Division III Planetary Systems Sciences Tel: via the Press Room +420-261-177-075 Ron Ekers IAU President Tel: via the Press Room +420-261-177-075 Catherine Cesarsky IAU President-Elect and member of the Planet Definition Committee Tel: via the Press Room +420-261-177-075 Richard Binzel Member of the Planet Definition Committee Tel: via the Press Room +420-261-177-075 Dava Sobel Author and historian, member of the Planet Definition Committee via the IAU Press Office Tel: +420-261-177-075 Mike Brown Discoverer of 2003 UB313 and a host of other planet candidates Via Caltech Media Relations Tel: +1-626-395-3226 E-mail: mbrown@caltech.edu PIO contact Lars Lindberg Christensen IAU Press Officer IAU GA 2006 Press office, Meeting Room 3.2 Prague Congress Center Tel: +420-261-177-075 Cellular: +49-173-3872-621 E-mail: lars@eso.org Links Additional material in this release package may be found in: http://www.iau2006.org/ * Draft Resolution * Question and Answer sheet * General Assembly Newspaper articles * Committee composition early July 2006. They culminated the two year process by reaching a unanimous consensus for a proposed new definition of the word "planet." Owen Gingerich, the Chair of the Planet Definition Committee says: "In July we had vigorous discussions of both the scientific and the cultural/historical issues, and on the second morning several members admitted that they had not slept well, worrying that we would not be able to reach a consensus. But by the end of a long day, the miracle had happened: we had reached a unanimous agreement."   Date: 17 Aug 2006 03:04:42 From: robert casey Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' > > According to the new draft definition, two conditions must be satisfied > for an object to be called a "planet." First, the object must be in > orbit around a star, while not being itself a star. Second, the object > must be large enough (or more technically correct, massive enough) for > its own gravity to pull it into a nearly spherical shape. The shape of > objects with mass above 5 x 1020 kg and diameter greater than 800 km > would normally be determined by self-gravity, but all borderline cases > would have to be established by observation. > > If the proposed Resolution is passed, the 12 planets in our Solar > System > will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, > Neptune, Pluto, Charon and 2003 UB313. Sedna is around 1000 km diameter, slightly smaller than Pluto. It should qualify as a planet. Quaoar looks to be on the hairy edge.     Date: 18 Aug 2006 15:45:25 From: Ken Arromdee Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' In article <e1REg.6941$Qf.2660@newsread2.news.pas.earthlink.net >, robert casey <wa2ise@ix.netcom.com > wrote: >Sedna is around 1000 km diameter, slightly smaller than Pluto. It >should qualify as a planet. Quaoar looks to be on the hairy edge. People always seem to forget that half the diameter means 1/8 the mass. A lot of the KBOs aren't so close to Pluto's "size" when you think in these terms. -- Ken Arromdee / arromdee_AT_rahul.net / http://www.rahul.net/arromdee "You know, you blow up one sun and suddenly everyone expects you to walk on water." --Samantha Carter, Stargate SG-1   Date: 17 Aug 2006 01:35:27 From: Zip Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' A slight rewording proposal. The draft states that Charon is a planet rather than a mere satellite of Pluto because both orbit around a barycenter which resides outside Pluto. Fine. But that "outside barycenter" criterion could backfire against the draft definition of "planet" (a planet "is in orbit around a star"). One could argue that Jupiter, for instance, is not a mere planet of the Sun, because both orbit around a barycenter (the barycenter of the solar system), which resides outside the Sun. In order to prevent this argument, and for accuracy's sake, IAU's formal definition of "planet" should be slightly generalized. Instead of stating: "(b) is in orbit around a star and is neither a star nor a satellite of a planet." It should state: "(b) is in orbit around the barycenter of a stellar system and is neither a star nor a satellite of a planet." Of course, "around a star" would stay an OK definition for common usage. What do you think? Zip     Date: 17 Aug 2006 11:44:53 From: Carsten A. Arnholm Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Zip wrote: > A slight rewording proposal. > > The draft states that Charon is a planet rather than a mere satellite > of Pluto because both orbit around a barycenter which resides outside > Pluto. Fine. > > But that "outside barycenter" criterion could backfire against the > draft definition of "planet" (a planet "is in orbit around a star"). > One could argue that Jupiter, for instance, is not a mere planet of > the Sun, because both orbit around a barycenter (the barycenter of > the solar system), which resides outside the Sun. > > In order to prevent this argument, and for accuracy's sake, IAU's > formal definition of "planet" should be slightly generalized. > > Instead of stating: > > "(b) is in orbit around a star and is neither a star nor a satellite > of a planet." > > It should state: > > "(b) is in orbit around the barycenter of a stellar system and is > neither a star nor a satellite of a planet." > > Of course, "around a star" would stay an OK definition for common > usage. > What do you think? Interesting, sounds like a good idea. The argument that Charon is "not a moon", due to the location of the barycenter of Pluto/Charon, seems to imply that it is by default promoted to be a planet (why?). The natural follow-up of such thinking is that Jupiter for the very same reason is not a planet and should be promoted to become a star. ehh.. but it conflicts with the definition of a star (unless Jupiter in the past has experienced nuclear fusion, in which case Jupiter is a star by definition). So Jupiter is currently by implication of the IAU proposal "not a moon, not a planet and not a star". :-) -- Carsten A. Arnholm http://arnholm.org/ N59.776 E10.457       Date: 17 Aug 2006 10:21:45 From: Greg Neill Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' "Carsten A. Arnholm" <arnholm@offline.no > wrote in message news:gpWdnfcNLckLp3nZ4p2dnA@telenor.com... > Zip wrote: > > A slight rewording proposal. > > > > The draft states that Charon is a planet rather than a mere satellite > > of Pluto because both orbit around a barycenter which resides outside > > Pluto. Fine. > > > > But that "outside barycenter" criterion could backfire against the > > draft definition of "planet" (a planet "is in orbit around a star"). > > One could argue that Jupiter, for instance, is not a mere planet of > > the Sun, because both orbit around a barycenter (the barycenter of > > the solar system), which resides outside the Sun. In the case of our solar system, the barycenter is only occasionally outside the surface of the Sun. > > > > In order to prevent this argument, and for accuracy's sake, IAU's > > formal definition of "planet" should be slightly generalized. > > > > Instead of stating: > > > > "(b) is in orbit around a star and is neither a star nor a satellite > > of a planet." > > > > It should state: > > > > "(b) is in orbit around the barycenter of a stellar system and is > > neither a star nor a satellite of a planet." > > > > Of course, "around a star" would stay an OK definition for common > > usage. > > What do you think? This might run into trouble in a multiple star system where the body orbits only one of the stars and the system's barycenter is entirely outside even the orbit.         Date: 18 Aug 2006 17:20:50 From: Carsten A. Arnholm Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Greg Neill wrote: >> Zip wrote: >>> A slight rewording proposal. >>> >>> The draft states that Charon is a planet rather than a mere >>> satellite of Pluto because both orbit around a barycenter which >>> resides outside Pluto. Fine. >>> >>> But that "outside barycenter" criterion could backfire against the >>> draft definition of "planet" (a planet "is in orbit around a star"). >>> One could argue that Jupiter, for instance, is not a mere planet of >>> the Sun, because both orbit around a barycenter (the barycenter of >>> the solar system), which resides outside the Sun. > > In the case of our solar system, the barycenter is only > occasionally outside the surface of the Sun. Which seems to imply that Jupiter is occasionally not a planet.... ? -- Carsten A. Arnholm http://arnholm.org/ N59.776 E10.457           Date: 18 Aug 2006 12:07:34 From: Greg Neill Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' "Carsten A. Arnholm" <arnholm@offline.no > wrote in message news:tsednavxjOBOR3jZ4p2dnA@telenor.com... > Greg Neill wrote: > >> Zip wrote: > >>> A slight rewording proposal. > >>> > >>> The draft states that Charon is a planet rather than a mere > >>> satellite of Pluto because both orbit around a barycenter which > >>> resides outside Pluto. Fine. > >>> > >>> But that "outside barycenter" criterion could backfire against the > >>> draft definition of "planet" (a planet "is in orbit around a star"). > >>> One could argue that Jupiter, for instance, is not a mere planet of > >>> the Sun, because both orbit around a barycenter (the barycenter of > >>> the solar system), which resides outside the Sun. > > > > In the case of our solar system, the barycenter is only > > occasionally outside the surface of the Sun. > > Which seems to imply that Jupiter is occasionally not a planet.... ? Not at all. The barycenter distinction is employed to distinguish planets from satellites when they are mutually bound objects.             Date: 19 Aug 2006 01:06:36 From: Carsten A. Arnholm Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Greg Neill wrote: > "Carsten A. Arnholm" <arnholm@offline.no> wrote in message > news:tsednavxjOBOR3jZ4p2dnA@telenor.com... >> Greg Neill wrote: >>>> Zip wrote: >>>>> A slight rewording proposal. >>>>> >>>>> The draft states that Charon is a planet rather than a mere >>>>> satellite of Pluto because both orbit around a barycenter which >>>>> resides outside Pluto. Fine. >>>>> >>>>> But that "outside barycenter" criterion could backfire against the >>>>> draft definition of "planet" (a planet "is in orbit around a >>>>> star"). One could argue that Jupiter, for instance, is not a mere >>>>> planet of the Sun, because both orbit around a barycenter (the >>>>> barycenter of the solar system), which resides outside the Sun. >>> >>> In the case of our solar system, the barycenter is only >>> occasionally outside the surface of the Sun. >> >> Which seems to imply that Jupiter is occasionally not a planet.... ? > > Not at all. The barycenter distinction is employed > to distinguish planets from satellites when they > are mutually bound objects. Ok. But planets are supposed to orbit stars, according the draft, not barycenters.....               Date: 18 Aug 2006 23:18:41 From: Greg Neill Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' "Carsten A. Arnholm" <arnholm@offline.no > wrote in message news:Y42dnSJDTcZh2nvZ4p2dnA@telenor.com... > Greg Neill wrote: > > "Carsten A. Arnholm" <arnholm@offline.no> wrote in message > > news:tsednavxjOBOR3jZ4p2dnA@telenor.com... > >> Greg Neill wrote: > >>>> Zip wrote: > >>>>> A slight rewording proposal. > >>>>> > >>>>> The draft states that Charon is a planet rather than a mere > >>>>> satellite of Pluto because both orbit around a barycenter which > >>>>> resides outside Pluto. Fine. > >>>>> > >>>>> But that "outside barycenter" criterion could backfire against the > >>>>> draft definition of "planet" (a planet "is in orbit around a > >>>>> star"). One could argue that Jupiter, for instance, is not a mere > >>>>> planet of the Sun, because both orbit around a barycenter (the > >>>>> barycenter of the solar system), which resides outside the Sun. > >>> > >>> In the case of our solar system, the barycenter is only > >>> occasionally outside the surface of the Sun. > >> > >> Which seems to imply that Jupiter is occasionally not a planet.... ? > > > > Not at all. The barycenter distinction is employed > > to distinguish planets from satellites when they > > are mutually bound objects. > > Ok. But planets are supposed to orbit stars, according the draft, not > barycenters..... > Right. Which means that the poster's contention that the barycenter criterion would sometimes imply that Jupiter is not a planet is specious from the outset.               Date: 18 Aug 2006 19:20:53 From: Davoud Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Carsten A. Arnholm wrote: > Ok. But planets are supposed to orbit stars, according the draft, not > barycenters... I think that the drafters thought that, since everyone ( /almost/ everyone, it turns out) knows that saying that one or more celestial bodies orbit another celestial body is only a convenient approximation -- /everything/ that can be said to be in orbit is in orbit around a barycenter, there was no need for redundant pedantry in the draft definition. Davoud -- usenet *at* davidillig dawt com                 Date: 19 Aug 2006 08:08:05 From: Zip Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' >>Ok. But planets are supposed to orbit stars, according the draft, not >>barycenters... > > > I think that the drafters thought that, since everyone ( /almost/ > everyone, it turns out) knows that saying that one or more celestial > bodies orbit another celestial body is only a convenient approximation > -- /everything/ that can be said to be in orbit is in orbit around a > barycenter, there was no need for redundant pedantry in the draft > definition. > > Davoud If it's a "convenient approximation" to say that Jupiter is a planet "in orbit around a star" and not a co-star in orbit around an autside barycenter, why isn't it a convenient approximation to say that Charon is a satellite "in orbit around a planet" and not a co-planet in orbit around an outside barycenter? That criterion is explicitly taken into acount to discriminate between satellites and planets (the Moon is a satellite of the Earth, but Charon is a co-planet of Pluto because of the outside barycenter) but is not explicitly taken into account to discriminate between planets and stars (the Earth is a planet of the Sun, should Jupiter be a co-star of the Sun?). That's what I find slighlty inconsistent. The outside barycenter criterion should be applied in both cases or shouldn't be applied at all. Zip   Date: 16 Aug 2006 21:18:20 From: Yama Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' This is some weird shit, yo. Why the heck they had to propose something so complex and unworkable? Since any definition is going to be more or less arbitrary, just put a simple, arbitrary limit somewhere and be done with it and don't bother about barycenters and double planets and whatnot.   Date: 16 Aug 2006 21:01:37 From: Painius Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Ron <baalke@earthlink.net > wrote in message... news:1155743341.245948.32920@m73g2000cwd.googlegroups.com... > > http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_release.html > > The IAU draft definition of "planet" and "plutons" > August 16, 2006 > Prague > > The world's astronomers, under the auspices of the International > Astronomical Union (IAU), have concluded two years of work defining the > difference between "planets" and the smaller "solar system bodies" such > as comets and asteroids. If the definition is approved by the > astronomers gathered 14-25 August 2006 at the IAU General Assembly in > Prague, our Solar System will include 12 planets, . . . Ohh... woe is me (and Asimov)... for now there are two *more* reasons for not considering our Moon, Selene, to be a major planet in its own right. 1) Nobody's gonna wanna see Selene as an "unlucky"... THIRTEENTH (13th) planet, and <g > 2) I read where the barycenter is arbitrarily supposed to be "outside" the arbitrarily dubbed "primary" object. Guess this makes unimportant and benign the fact that the Earth/Moon barycenter is fully 3/4 of the way from Earth's center to her surface. Personally, i think Isaac Asimov did a FAR better job defining a major planet than these clearly overworked, overtired, "by the end of the day we'll give in to anything" astronomers. There's a bit more to it than just gravity and barycenters. happy days and... starry starry nights! -- Indelibly yours, Paine http://www.painellsworth.net http://www.savethechildren.org     Date: From: Subject:   Date: 16 Aug 2006 13:52:29 From: Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Carsten A. Arnholm wrote: > Davoud wrote: > > baalke@earthlink.net > >>> If the proposed Resolution is passed, the 12 planets in our Solar > >>> System will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, > >>> Uranus, Neptune, Pluto, Charon and 2003 UB313. > > George Dishman: > >> If a planet "must be in orbit around a star", how can > >> both Pluto and Charon qualify? > > Footnote 2 reads: "For two or more objects comprising a multiple > > object system, the primary object is designated a planet if it > > independently satisfies the conditions above. A secondary object > > satisfying these conditions is also designated a planet if the system > > barycentre resides outside the primary. Secondary objects not > > satisfying these criteria > > are "satellites". Under this definition, Pluto's companion Charon is a > > planet, making Pluto-Charon a double planet. > So when The Moon recedes enough from the Earth to lift the barycentre > outside the Earth, then The Moon is no longer "The Moon" but "The Planet"? > Probably a very wrong calculation but as The Moon (as we know it) recedes > =A8~4 cm per year and the barycentre is 1750 km below the Earth's surface, > then "The Moon" will become "The Planet" in approximately 1750 * 1000*10= 0 / > 4 years=3D ~43 million years ?? > Not a long time really, but will the IUA definition last this long. My bet > is "no". Tweak the definition and make the Moon a planet! If Pluto/Charon can be a double planet then so can Earth/Moon! I suggest the same barycenter out of the primary but figure it at a distance equal to the radius of gravitational influence of the primary. Tom Clarke     Date: 18 Aug 2006 01:48:20 From: osdfey Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' On Wed, 16 Aug 2006 13:52:29 -0700, polymath.tlc wrote: > Carsten A. Arnholm wrote: >> Davoud wrote: >> > baalke@earthlink.net > >> >>> If the proposed Resolution is passed, the 12 planets in our Solar >> >>> System will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, >> >>> Uranus, Neptune, Pluto, Charon and 2003 UB313. > >> > George Dishman: >> >> If a planet "must be in orbit around a star", how can >> >> both Pluto and Charon qualify? > >> > Footnote 2 reads: "For two or more objects comprising a multiple >> > object system, the primary object is designated a planet if it >> > independently satisfies the conditions above. A secondary object >> > satisfying these conditions is also designated a planet if the system >> > barycentre resides outside the primary. Secondary objects not >> > satisfying these criteria >> > are "satellites". Under this definition, Pluto's companion Charon is a >> > planet, making Pluto-Charon a double planet. > >> So when The Moon recedes enough from the Earth to lift the barycentre >> outside the Earth, then The Moon is no longer "The Moon" but "The Planet"? > >> Probably a very wrong calculation but as The Moon (as we know it) recedes >> ¨~4 cm per year and the barycentre is 1750 km below the Earth's surface, >> then "The Moon" will become "The Planet" in approximately 1750 * 1000*100 / >> 4 years= ~43 million years ?? > >> Not a long time really, but will the IUA definition last this long. My bet >> is "no". > > Tweak the definition and make the Moon a planet! > why not > If Pluto/Charon can be a double planet then so can Earth/Moon! > > I suggest the same barycenter out of the primary but figure it at a > distance equal to the radius of gravitational influence of the primary. > > Tom Clarke   Date: 16 Aug 2006 13:39:10 From: Greg Crinklaw Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' There are many interests to serve in this question; scientific, historical, and practical. The problem is that they are often mutually exclusive. Historically we want to preserve the definitive we've been using as much as possible. Scientifically we want something that won't be an albatross around the necks of future generations who would have to deal with yet another meaningless taxonomy created before things were well enough understood or surveyed. Practicality, we don't want to have to teach young kids the names of potentially dozens of planets (that keeps changing) and we want to avoid the arguing and grandstanding every time a new discovery is made. Let us stand back for a minute and examine what the actual problem is with the current system. The root of the problem is that we are trying to stuff a continuum into arbitrary boxes. So let's tackle the problem at its root. This is something we should simply let go of. Forget about trying to sort planets by size or mass or shape. Anything along these lines will always be arbitrary because bodies come in a continuum of sizes, shapes and masses. That's just the way it is. Even the idea of a spherical body is arbitrary. The thing is, how spherical? There are bound to be bodies discovered that lie near the boundary we choose and they will be arbitrarily included or excluded. So here's what I'd do (to have our cake and eat it too). (1) Call everything a planet. Seriously. Define "planet" as any non-stellar natural body orbiting a star (either directly or not). (2) Create three scientific sub groupings of planets based on their primary composition: rocky planets, icy planets, and gaseous planets. (3) Create a popular subgroup called "traditional planets" in which there will always be nine planets (Pluto has been around long enough). We can still have asteroids and comets, but they will no longer be considered rigorous scientific definitions (they never really were anyhow). Lose "minor planet" entirely. Technically an asteroid would be a rocky planet. Technically a comet would be an icy planet. I know the size distinction seems important and obvious, but it's a trap! So instead of kludging a fix, let's avoid the trap entirely. Scientific papers might be written about the icy planet Hale-Bopp, but we'd still call it a comet in every day use (where a precise definition isn't required.) Scientists can build on the composition taxonomy as more data comes in. Traditionalists can keep their nine planets. School teachers can keep teaching what they have been and kids everywhere can breathe a sigh of relief. Everybody's happy. So there 'ya go. ;-) -- 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: 18 Aug 2006 03:49:52 From: POA Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Greg Crinklaw wrote: > There are many interests to serve in this question; scientific, > historical, and practical. The problem is that they are often mutually > exclusive. Historically we want to preserve the definitive we've been > using as much as possible. Scientifically we want something that won't > be an albatross around the necks of future generations who would have to > deal with yet another meaningless taxonomy created before things were > well enough understood or surveyed. Practicality, we don't want to have > to teach young kids the names of potentially dozens of planets (that > keeps changing) and we want to avoid the arguing and grandstanding every > time a new discovery is made. > > Let us stand back for a minute and examine what the actual problem is > with the current system. The root of the problem is that we are trying > to stuff a continuum into arbitrary boxes. So let's tackle the problem > at its root. This is something we should simply let go of. > > Forget about trying to sort planets by size or mass or shape. Anything > along these lines will always be arbitrary because bodies come in a > continuum of sizes, shapes and masses. That's just the way it is. Even > the idea of a spherical body is arbitrary. The thing is, how spherical? > There are bound to be bodies discovered that lie near the boundary we > choose and they will be arbitrarily included or excluded. > > So here's what I'd do (to have our cake and eat it too). > > (1) Call everything a planet. Seriously. Define "planet" as any > non-stellar natural body orbiting a star (either directly or not). > > (2) Create three scientific sub groupings of planets based on their > primary composition: rocky planets, icy planets, and gaseous planets. > > (3) Create a popular subgroup called "traditional planets" in which > there will always be nine planets (Pluto has been around long enough). > > We can still have asteroids and comets, but they will no longer be > considered rigorous scientific definitions (they never really were > anyhow). Lose "minor planet" entirely. Technically an asteroid would > be a rocky planet. Technically a comet would be an icy planet. > > I know the size distinction seems important and obvious, but it's a > trap! So instead of kludging a fix, let's avoid the trap entirely. > Scientific papers might be written about the icy planet Hale-Bopp, but > we'd still call it a comet in every day use (where a precise definition > isn't required.) > > Scientists can build on the composition taxonomy as more data comes in. > > Traditionalists can keep their nine planets. > > School teachers can keep teaching what they have been and kids > everywhere can breathe a sigh of relief. > > Everybody's happy. > > So there 'ya go. ;-) > > -- > 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 I agree with your conceptual analysis however, this is a beaurocratically charged issue and politics will dedide it, for the beaurocratic worst. I doubt that Pluto cares!     Date: 18 Aug 2006 11:47:33 From: Greg Crinklaw Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Hi Mark, mark.foskey@gmail.com wrote: > Greg Crinklaw wrote: >> Scientifically we want something that won't >> be an albatross around the necks of future generations who would have to >> deal with yet another meaningless taxonomy created before things were >> well enough understood or surveyed. > > That is precisely what the proposed definition does, which is I think > part of your point. A friend of mine made the point that they won't > have enough data to come up with a really good taxonomy until they've > got detailed data on dozen more solar systems or so. I see your point, I really do, and I agree, but only partly. If we take the position that no scientific definition can be made at this time, then fine. But why dress up a non-science-based definition and pretend it's scientific? As a scientist that troubles me. >> Forget about trying to sort planets by size or mass or shape. Anything >> along these lines will always be arbitrary because bodies come in a >> continuum of sizes, shapes and masses. > > By itself, that doesn't mean we shouldn't do it. The English language > would be poorer if it didn't have both the words 'hill' and 'mountain'. Another good point. But again, what I am troubled by is a political compromise that has resulted in an arbitrary definition that sounds scientific but in truth has no scientific basis. Throw in all the practical problems this "solution" causes and I think the whole idea stinks. The *only* thing this solution really has going for it is that it offers a compromise that might break the deadlock between those who want Pluto to be a planet and those who do not. What an awful criterion! Greg -- 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: 16 Aug 2006 19:26:41 From: George Dishman Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' <baalke@earthlink.net > wrote in message news:1155743341.245948.32920@m73g2000cwd.googlegroups.com... > http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_release.html > > The IAU draft definition of "planet" and "plutons" > August 16, 2006 > 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." > > According to the new draft definition, two conditions must be satisfied > for an object to be called a "planet." First, the object must be in > orbit around a star, while not being itself a star. ... > > If the proposed Resolution is passed, the 12 planets in our Solar System > will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, > Neptune, Pluto, Charon and 2003 UB313. If a planet "must be in orbit around a star", how can both Pluto and Charon qualify? If the goal was to find a "scientific basis for a new definition of 'planet'" then surely it needs to include a criterion to segregate planet/moon systems from double planet systems, for example based on the mass ratio. > ... Second, the object > must be large enough (or more technically correct, massive enough) for > its own gravity to pull it into a nearly spherical shape. The shape of > objects with mass above 5*10^20 kg and diameter greater than 800 km > would normally be determined by self-gravity, but all borderline cases > would have to be established by observation. If they aren't adopting 5*10^20 kg as the criterion but "by observation", then to be scientific it needs some definition of roundness, for example would Mars no longer be a planet if Olympus Mons was too big a pimple? Maximum rms deviation from oblate spheroid sounds like the sort of thing that is needed. George     Date: 16 Aug 2006 15:17:22 From: Davoud Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' baalke@earthlink.net > > If the proposed Resolution is passed, the 12 planets in our Solar System > > will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, > > Neptune, Pluto, Charon and 2003 UB313. George Dishman: > If a planet "must be in orbit around a star", how can > both Pluto and Charon qualify? Footnote 2 reads: "For two or more objects comprising a multiple object system, the primary object is designated a planet if it independently satisfies the conditions above. A secondary object satisfying these conditions is also designated a planet if the system barycentre resides outside the primary. Secondary objects not satisfying these criteria are "satellites". Under this definition, Pluto's companion Charon is a planet, making Pluto-Charon a double planet. Davoud -- usenet *at* davidillig dawt com       Date: 16 Aug 2006 22:47:55 From: Carsten A. Arnholm Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Davoud wrote: > baalke@earthlink.net > >>> If the proposed Resolution is passed, the 12 planets in our Solar >>> System will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, >>> Uranus, Neptune, Pluto, Charon and 2003 UB313. > > George Dishman: >> If a planet "must be in orbit around a star", how can >> both Pluto and Charon qualify? > > Footnote 2 reads: "For two or more objects comprising a multiple > object system, the primary object is designated a planet if it > independently satisfies the conditions above. A secondary object > satisfying these conditions is also designated a planet if the system > barycentre resides outside the primary. Secondary objects not > satisfying these criteria > are "satellites". Under this definition, Pluto's companion Charon is a > planet, making Pluto-Charon a double planet. > > Davoud So when The Moon recedes enough from the Earth to lift the barycentre outside the Earth, then The Moon is no longer "The Moon" but "The Planet"? Probably a very wrong calculation but as The Moon (as we know it) recedes ¨~4 cm per year and the barycentre is 1750 km below the Earth's surface, then "The Moon" will become "The Planet" in approximately 1750 * 1000*100 / 4 years= ~43 million years ?? Not a long time really, but will the IUA definition last this long. My bet is "no". -- Carsten A. Arnholm http://arnholm.org/ N59.776 E10.457       Date: 16 Aug 2006 20:50:56 From: George Dishman Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' "Davoud" <star@sky.net > wrote in message news:160820061517225545%star@sky.net... > baalke@earthlink.net > >> > If the proposed Resolution is passed, the 12 planets in our Solar >> > System >> > will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, >> > Neptune, Pluto, Charon and 2003 UB313. > > George Dishman: >> If a planet "must be in orbit around a star", how can >> both Pluto and Charon qualify? > > Footnote 2 reads: "For two or more objects comprising a multiple object > system, the primary object is designated a planet if it independently > satisfies the conditions above. A secondary object satisfying these > conditions is also designated a planet if the system barycentre resides > outside the primary. Secondary objects not satisfying these criteria > are "satellites". Under this definition, Pluto's companion Charon is a > planet, making Pluto-Charon a double planet. Apologies, I had missed the link to the formal definition. Thanks for the hint. George     Date: 18 Aug 2006 03:46:32 From: POA Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' George Dishman wrote: > <baalke@earthlink.net> wrote in message > news:1155743341.245948.32920@m73g2000cwd.googlegroups.com... > > http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_release.html > > > > The IAU draft definition of "planet" and "plutons" > > August 16, 2006 > > 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." > > > > According to the new draft definition, two conditions must be satisfied > > for an object to be called a "planet." First, the object must be in > > orbit around a star, while not being itself a star. ... > > > > If the proposed Resolution is passed, the 12 planets in our Solar System > > will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, > > Neptune, Pluto, Charon and 2003 UB313. > > If a planet "must be in orbit around a star", how can > both Pluto and Charon qualify? > > If the goal was to find a "scientific basis for a new > definition of 'planet'" then surely it needs to include > a criterion to segregate planet/moon systems from double > planet systems, for example based on the mass ratio. > > > ... Second, the object > > must be large enough (or more technically correct, massive enough) for > > its own gravity to pull it into a nearly spherical shape. The shape of > > objects with mass above 5*10^20 kg and diameter greater than 800 km > > would normally be determined by self-gravity, but all borderline cases > > would have to be established by observation. > > If they aren't adopting 5*10^20 kg as the criterion > but "by observation", then to be scientific it needs > some definition of roundness, for example would Mars > no longer be a planet if Olympus Mons was too big a > pimple? Maximum rms deviation from oblate spheroid > sounds like the sort of thing that is needed. > > George What has roundness got to do with anything!   Date: 16 Aug 2006 10:19:13 From: Double-A Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' > According to the new draft definition, two conditions must be satisfied > for an object to be called a "planet." First, the object must be in > orbit around a star, while not being itself a star. Second, the object > must be large enough (or more technically correct, massive enough) for > its own gravity to pull it into a nearly spherical shape. The shape of > objects with mass above 5 x 1020 kg and diameter greater than 800 km > would normally be determined by self-gravity, but all borderline cases > would have to be established by observation. I wish they would have said "ellipsoidal" as rapidly spinning bodies can be quit oblate. http://www.gps.caltech.edu/~mbrown/2003EL61/index.html Double-A     Date: 17 Aug 2006 07:43:14 From: Paul Schlyter Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' In article <1155748753.552783.53320@74g2000cwt.googlegroups.com >, Double-A <double-aa@hush.ai > wrote: >> According to the new draft definition, two conditions must be satisfied >> for an object to be called a "planet." First, the object must be in >> orbit around a star, while not being itself a star. Second, the object >> must be large enough (or more technically correct, massive enough) for >> its own gravity to pull it into a nearly spherical shape. The shape of >> objects with mass above 5 x 1020 kg and diameter greater than 800 km >> would normally be determined by self-gravity, but all borderline cases >> would have to be established by observation. > > I wish they would have said "ellipsoidal" as rapidly spinning bodies > can be quit oblate. I think they included this in "nearly spherical". They're not suggesting that Jupiter or Saturn should be considered non-planets, even though their shapes quite visibly deviates from spherical. > http://www.gps.caltech.edu/~mbrown/2003EL61/index.html However a rotational ellipsoid wouldn't look like THAT! If the ellipcity was due to rotation, the apparent cross section shape would remain constant as the body rotated. It wouldn't vary as it does for 2003 EL61 ! -- ------ Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN e-mail: pausch at stockholm dot bostream dot se WWW: http://stjarnhimlen.se/     Date: 17 Aug 2006 16:34:04 From: Steve Willner Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' In article <1155748753.552783.53320@74g2000cwt.googlegroups.com >, "Double-A" <double-aa@hush.ai > writes: > I wish they would have said "ellipsoidal" as rapidly spinning bodies > can be quit oblate. The draft definition is at http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_resolution.html It says "hydrostatic equilibrium shape," which covers both rapid rotation and tidal distortion. Nobody wants to drop Jupiter as a planet. :-) I think the definition covers the other points that have been raised, though I personally am not sure why we need double planets. If we are going to have them, though, putting Earth/Moon close to the boundary makes sense. There's no problem with "big mountains" on otherwise round planets. Gravitation and rock strength set a limit on how big such mountains can be. By the way, I quite like the picture on the main IAU page (www.iau.org). :-) I didn't know it was there until a colleague mentioned it to me a few days ago. -- Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.)       Date: 17 Aug 2006 13:44:31 From: Brian Tung Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Steve Willner wrote: > By the way, I quite like the picture on the main IAU page > (www.iau.org). :-) I didn't know it was there until a colleague > mentioned it to me a few days ago. That web site now redirects to a mirror. For those of us who didn't catch the picture you're talking about, what was it? -- 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: 18 Aug 2006 12:50:36 From: Steve Willner Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' In article <ec2kff$pu0$1@praesepe.isi.edu >, brian@isi.edu (Brian Tung) writes: > That web site now redirects to a mirror. For those of us who didn't > catch the picture you're talking about, what was it? Bad timing there! Sorry. The original page is mirrored at http://www.iau2006.org/mirror/www.iau.org/HOME.2.0.html and there's a better version of the image at http://sscws1.ipac.caltech.edu/Imagegallery/image.php?image_name=ssc2003-06c The beautiful color image was made by Robert Hurt at the Spitzer Science Center. It's old, but I was amused to find it on the IAU home page. If you like that one, take a look at the zoomable image of M31 ("Andromeda Galaxy") at http://www.spitzer.caltech.edu/Media/mediaimages/zooms/index.shtml -- Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.)   Date: 17 Aug 2006 14:26:20 From: beav Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' On 16 Aug 2006 08:49:01 -0700, baalke@earthlink.net wrote: >http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_release.html > >The IAU draft definition of "planet" and "plutons" >August 16, 2006 >Prague > >The world's astronomers, under the auspices of the International >Astronomical Union (IAU), have concluded two years of work defining the >difference between "planets" and the smaller "solar system bodies" such >as comets and asteroids. If the definition is approved by the >astronomers gathered 14-25 August 2006 at the IAU General Assembly in >Prague, our Solar System will include 12 planets, with more to come: >eight classical planets that dominate the system, three planets in a >new >and growing category of "plutons" - Pluto-like objects - and Ceres. >Pluto remains a planet and is the prototype for the new category of >"plutons." > >With the advent of powerful new telescopes on the ground and in space, >planetary astronomy has gone though an exciting development over the >past decade. For thousands of years very little was known about the >planets other than they were objects that moved in the sky with respect >to the background of fixed stars. In fact the word "planet" comes from >the Greek word for "wanderer". But today hosts of newly discovered >large >objects in the outer regions of our Solar System present a challenge to >our historically based definition of a "planet". > >At first glance one should think that it is easy to define what a >planet >is - a large and round body. On second thought difficulties arise, as >one could ask "where is the lower limit?" - how large, and how round >should an asteroid be before it becomes a planet - as well as "where is >the upper limit?" - how large can a planet be before it becomes a brown >dwarf or a star? > >IAU President Ron Ekers explains the rational behind a planet >definition: "Modern science provides much more knowledge than the >simple >fact that objects orbiting the Sun appear to move with respect to the >background of fixed stars. For example, recent new discoveries have >been >made of objects in the outer regions of our Solar System that have >sizes >comparable to and larger than Pluto. These discoveries have rightfully >called into question whether or not they should be considered as new >'planets.' " > >The International Astronomical Union has been the arbiter of planetary >and satellite nomenclature since its inception in 1919. The world's >astronomers, under the auspices of the IAU, have had official >deliberations on a new definition for the word "planet" for nearly two >years. IAU's top, the so-called Executive Committee, led by Ekers, >formed a Planet Definition Committee (PDC) comprised by seven persons >who were astronomers, writers, and historians with broad international >representation. This group of seven convened in Paris in late June and >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." > >According to the new draft definition, two conditions must be satisfied >for an object to be called a "planet." First, the object must be in >orbit around a star, while not being itself a star. Second, the object >must be large enough (or more technically correct, massive enough) for >its own gravity to pull it into a nearly spherical shape. The shape of >objects with mass above 5 x 1020 kg and diameter greater than 800 km >would normally be determined by self-gravity, but all borderline cases >would have to be established by observation. > >If the proposed Resolution is passed, the 12 planets in our Solar >System >will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, >Neptune, Pluto, Charon and 2003 UB313. The name 2003 UB313 is >provisional, as a "real" name has not yet been assigned to this object. >A decision and announcement of a new name are likely not to be made >during the IAU General Assembly in Prague, but at a later time. The >naming procedures depend on the outcome of the Resolution vote. There >will most likely be more planets announced by the IAU in the future. >Currently a dozen "candidate planets" are listed on IAU's "watchlist" >which keeps changing as new objects are found and the physics of the >existing candidates becomes better known. > >The IAU draft Resolution also defines a new category of planet for >official use: "pluton". Plutons are distinguished from classical >planets >in that they reside in orbits around the Sun that take longer than 200 >years to complete (i.e. they orbit beyond Neptune). Plutons typically >have orbits that are highly tilted with respect to the classical >planets >(technically referred to as a large orbital inclination). Plutons also >typically have orbits that are far from being perfectly circular >(technically referred to as having a large orbital eccentricity). All >of >these distinguishing characteristics for plutons are scientifically >interesting in that they suggest a different origin from the classical >planets. > >The draft "Planet Definition" Resolution will be discussed and refined >during the General Assembly and then it (plus four other Resolutions) >will be presented for voting at the 2nd session of the GA 24 August >between 14:00 and 17:30 CEST. > >Notes for editors > >The IAU is the international astronomical organisation that brings >together distinguished astronomers from all nations of the world. IAU's >mission is to promote and safeguard the science of astronomy in all its >aspects through international cooperation. Founded in 1919, the IAU is >the world's largest professional body for astronomers. The IAU General >Assembly is held every three years and is one of the largest and most >diverse meetings in the astronomical community's calendar. > >Science contacts (the persons below can all be reached via the IAU GA >Press Office, see bottom) > >Owen Gingerich >IAU Planet Definition Committee Chair >Tel: via the Press Room +420-261-177-075 > >Iwan Williams >President, IAU Division III Planetary Systems Sciences >Tel: via the Press Room +420-261-177-075 > >Ron Ekers >IAU President >Tel: via the Press Room +420-261-177-075 > >Catherine Cesarsky >IAU President-Elect and member of the Planet Definition Committee >Tel: via the Press Room +420-261-177-075 > >Richard Binzel >Member of the Planet Definition Committee >Tel: via the Press Room +420-261-177-075 > >Dava Sobel >Author and historian, member of the Planet Definition Committee >via the IAU Press Office >Tel: +420-261-177-075 > >Mike Brown >Discoverer of 2003 UB313 and a host of other planet candidates >Via Caltech Media Relations >Tel: +1-626-395-3226 >E-mail: mbrown@caltech.edu > >PIO contact >Lars Lindberg Christensen >IAU Press Officer >IAU GA 2006 Press office, Meeting Room 3.2 >Prague Congress Center >Tel: +420-261-177-075 >Cellular: +49-173-3872-621 >E-mail: lars@eso.org > >Links > >Additional material in this release package may be found in: >http://www.iau2006.org/ > > * Draft Resolution > * Question and Answer sheet > * General Assembly Newspaper articles > * Committee composition > > >early July 2006. They culminated the two year process by reaching a >unanimous consensus for a proposed new definition of the word "planet." > >Owen Gingerich, the Chair of the Planet Definition Committee says: "In >July we had vigorous discussions of both the scientific and the >cultural/historical issues, and on the second morning several members >admitted that they had not slept well, worrying that we would not be >able to reach a consensus. But by the end of a long day, the miracle >had >happened: we had reached a unanimous agreement." jeez Owen. worry less about an agreement, and worry more about getting a good agreement. A whole lot of discussion about a bad definition. If Ceres is a planet, what about the rest of the mass of the asteroid belt? Is it possible that Ceres is round from getting chipped round by impacts? or how about it being round because of its fast rotation and the sun subliming ice that gets cold trapped back on the surface? once DAWN gets there, we'll know, but calling Ceres a planet is weird. if a region is so devoid of controlling mass (an existing planet), its simply a debris field. what if a "planet" ("hydrostatically round object") was parked at one of the lagrangian points ahead or behind a planet? ditto for the Kuiper belt. just because pluto was the first discovered, and least eccentric member of a disorganized highly eccentric swarm of ice balls, doesn't make it a planet, especially when other members of its class are finally found. numbering the asteroids is a very workable system. No one is ever going to confuse ceres as a "planet". numbering the KBOs AS KBOs or "plutons" is just as workable. the answer is simple: demote pluto. consider another star system that has multiple asteroid belts and a diffuse KB region. you could have red/brown dwarfs with thousands of "planets," if you use this currently proposed loosening of the current understanding. imagine a blue giant with millions of "planets." this idea is silly and absolutely arbitrary. I disagree with this proposal. not that it matters what I think..     Date: 17 Aug 2006 11:40:52 From: Davoud Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' beav wrote: > A whole lot of discussion about a bad definition. If Ceres is a > planet, what about the rest of the mass of the asteroid belt? Is it > possible that Ceres is round from getting chipped round by impacts? Is it /possible/ over the age of the Solar System? I don't know, but it doesn't matter because that's not how Ceres got to be a spheroid. It's not as if the mass of Ceres is unknown. (9.5X10E20 kg, or (4.39+-.04)X10E-10 Solar Masses according to some estimates, sufficient to make it spherical.) > or how about it being round because of its fast rotation and the sun > subliming ice that gets cold trapped back on the surface? once DAWN > gets there, we'll know, but calling Ceres a planet is weird. If the IAU adopts a definition of "planet" that happens to include Ceres, calling Ceres a planet is /ipso/ /facto/ not weird. > if a region is so devoid of controlling mass (an existing planet), its > simply a debris field. There is no region in the Universe that is devoid of "controlling mass." > what if a "planet" ("hydrostatically round > object") was parked at one of the lagrangian points ahead or behind a > planet? The definition is suitable to handle that situation. > just because pluto was the first > discovered, and least eccentric member of a disorganized highly > eccentric swarm of ice balls, doesn't make it a planet, especially > when other members of its class are finally found. Let's get something clear. The IAO definition does not say that /you/ have to call Pluto a planet. You can call it Billy Bob if you want to. Other members of its class have already been found, and one of them, UB313 ("Xena") will been called a planet under the proposed definition. > numbering the asteroids is a very workable system. No one is ever > going to confuse ceres as a "planet"... No more confusion. Ceres will be a planet under the proposed definition. > consider another star system that has multiple asteroid belts and a > diffuse KB region. you could have red/brown dwarfs with thousands of > "planets," if you use this currently proposed loosening of the current > understanding. imagine a blue giant with millions of "planets." A little too speculative at the moment. Sounds like something the proposed definition could deal with if it should arise, however. And if it can't deal with the situation, the definition can be changed. > this idea is silly and absolutely arbitrary. Huh? Life is arbitrary. Get used to it. > I disagree with this proposal. not that it matters what I think.. Now you got it. As I said above, the proposal doesn't apply to you. Call these objects whatever you want without reference to what the official designation is and you'll be fine. Take a nap, settle down a bit. Davoud -- usenet *at* davidillig dawt com       Date: 17 Aug 2006 18:23:54 From: robert casey Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' > >>numbering the asteroids is a very workable system. No one is ever >>going to confuse ceres as a "planet"... > > > No more confusion. Ceres will be a planet under the proposed definition. > Ceres would be a planet with an asteroid number (#1). I suppose we could assign the big nine planets numbers too. Whatever sequentially comes up. Earth might get #90214, Venus #90213, Mars #90215, and so on.... :-). What about the Sun? Maybe it should be HD1? Milky Way galaxy should get NCG1? :-)         Date: 17 Aug 2006 23:21:33 From: Davoud Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' robert casey wrote: > Ceres would be a planet with an asteroid number (#1). OK. > I suppose we could assign the big nine planets numbers too. Sure, Why not? What do you mean by the "big nine?" UB313 "Xena" is larger than Pluto. <http://news.bbc.co.uk/1/hi/sci/tech/4667100.stm > > Whatever sequentially comes up. Earth might get #90214, Venus #90213, > Mars #90215, and so on.... :-). Absolutely. > What about the Sun? Maybe it should be HD1? Milky Way galaxy > should get NCG1? :-) Yes, definitely. In other words, it is what: You are free to call these objects anything you wish. The IAU is going to decide what /it/ wants to call them, but you need not abide by that, so long as you don't mind being misunderstood by other astronomers. Davoud -- usenet *at* davidillig dawt com           Date: 22 Aug 2006 18:22:12 From: robert casey Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' > In other words, it is what: You are free to call these objects anything > you wish. The IAU is going to decide what /it/ wants to call them, but > you need not abide by that, so long as you don't mind being > misunderstood by other astronomers. > And I could spend $50 or whatever it is now for some company to "name a star" after myself. Of course it's a waste of money....       Date: 18 Aug 2006 16:02:17 From: beav Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' On Thu, 17 Aug 2006 11:40:52 -0400, Davoud <star@sky.net > wrote: >beav wrote: >> A whole lot of discussion about a bad definition. If Ceres is a >> planet, what about the rest of the mass of the asteroid belt? Is it >> possible that Ceres is round from getting chipped round by impacts? > >Is it /possible/ over the age of the Solar System? I don't know, but it >doesn't matter because that's not how Ceres got to be a spheroid. It's >not as if the mass of Ceres is unknown. (9.5X10E20 kg, or >(4.39+-.04)X10E-10 Solar Masses according to some estimates, sufficient >to make it spherical.) sufficient. but necessary? this is an arbitrary definition. <shrug > > >> or how about it being round because of its fast rotation and the sun >> subliming ice that gets cold trapped back on the surface? once DAWN >> gets there, we'll know, but calling Ceres a planet is weird. > >If the IAU adopts a definition of "planet" that happens to include >Ceres, calling Ceres a planet is /ipso/ /facto/ not weird. > >> if a region is so devoid of controlling mass (an existing planet), its >> simply a debris field. > >There is no region in the Universe that is devoid of "controlling mass." right. so a smattering of mass smeared throughout a region is meaningless if one object exceeds the arbitrary mass limit? > >> what if a "planet" ("hydrostatically round >> object") was parked at one of the lagrangian points ahead or behind a >> planet? > >The definition is suitable to handle that situation. > >> just because pluto was the first >> discovered, and least eccentric member of a disorganized highly >> eccentric swarm of ice balls, doesn't make it a planet, especially >> when other members of its class are finally found. > >Let's get something clear. The IAO definition does not say that /you/ >have to call Pluto a planet. You can call it Billy Bob if you want to. >Other members of its class have already been found, and one of them, >UB313 ("Xena") will been called a planet under the proposed definition. definitions are supposed to be internally consistent. i agree. anyone can call anything whatever they'd like. that's not the point. this isn't consistent. its as arbitrary as if i did want to call it billy bob. the IAU "democratically" arrives at this "standard." its kind of like the old definition of the - the distance from the kings knuckle to the end of his finger. maybe it worked in the 13th century, but it shouldn't be applied now. > >> numbering the asteroids is a very workable system. No one is ever >> going to confuse ceres as a "planet"... > >No more confusion. Ceres will be a planet under the proposed definition. > >> consider another star system that has multiple asteroid belts and a >> diffuse KB region. you could have red/brown dwarfs with thousands of >> "planets," if you use this currently proposed loosening of the current >> understanding. imagine a blue giant with millions of "planets." > >A little too speculative at the moment. Sounds like something the >proposed definition could deal with if it should arise, however. And if >it can't deal with the situation, the definition can be changed. > >> this idea is silly and absolutely arbitrary. > >Huh? Life is arbitrary. Get used to it. science isn't arbitrary. we're not talking about "life" here. > >> I disagree with this proposal. not that it matters what I think.. > >Now you got it. As I said above, the proposal doesn't apply to you. >Call these objects whatever you want without reference to what the >official designation is and you'll be fine. Take a nap, settle down a >bit. > >Davoud are you a voting member of the IAU panel that's been insulted by my not being excited about this goofy proposal? if so, too bad. if not, buzz off.         Date: 18 Aug 2006 12:47:37 From: Davoud Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' beav: > >> A whole lot of discussion about a bad definition. If Ceres is a > >> planet, what about the rest of the mass of the asteroid belt? Is it > >> possible that Ceres is round from getting chipped round by impacts? Davoud: > > ...it doesn't matter because that's not how Ceres got to be a spheroid. > > It's not as if the mass of Ceres is unknown. (9.5X10E20 kg, or > > (4.39+-.04)X10E-10 Solar Masses according to some estimates, sufficient > > to make it spherical.) > sufficient. but necessary? Yes, a certain minimum mass is required if a celestial body is to be spherical. > this is an arbitrary definition. That's right. So what? > >There is no region in the Universe that is devoid of "controlling mass." > right. so a smattering of mass smeared throughout a region is > meaningless if one object exceeds the arbitrary mass limit? You're making stuff up as you go along. I don't see that anywhere in the IAU proposal. To assert that the other side is claiming something that it is not doesn't speak well for your skill as a disputant. > definitions are supposed to be internally consistent. i agree. anyone > can call anything whatever they'd like. that's not the point. > this isn't consistent. its as arbitrary as if i did want to call it > billy bob. the IAU "democratically" arrives at this "standard." its > kind of like the old definition of the - the distance from the kings > knuckle to the end of his finger. maybe it worked in the 13th > century, but it shouldn't be applied now. You don't seem to understand that the IAU definition, if adopted, does not have the force of law. These objects are like all other things that exist in that you may call them whatever you wish. I don't care what /you/ call them or whether you like the IAU definition. Why can't you reciprocate? > >Huh? Life is arbitrary. Get used to it. > science isn't arbitrary. we're not talking about "life" here. This isn't science. There is nothing discoverable about these bodies that would classify them unequivocally so that no human judgement is needed, so any definition must be arbitrary. The decision on whether to call something a tree or a cow is also arbitrary. You do not need to abide by any of these conventions. You may, if you wish, milk your tree under the shade of a cow. > >> I disagree with this proposal. not that it matters what I think.. > > > >Now you got it. As I said above, the proposal doesn't apply to you. > >Call these objects whatever you want without reference to what the > >official designation is and you'll be fine. Take a nap, settle down a > >bit. > are you a voting member of the IAU panel that's been insulted by my > not being excited about this goofy proposal? if so, too bad. if not, > buzz off. Are you some egotistical maniac who thinks that anyone cares whether you are "excited" by this most sensible proposal? If so, too bad. Wake up and sniff your irrelevance. Davoud -- usenet *at* davidillig dawt com           Date: 18 Aug 2006 21:19:06 From: beav Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' On Fri, 18 Aug 2006 12:47:37 -0400, Davoud <star@sky.net > wrote: >beav: >> >> A whole lot of discussion about a bad definition. If Ceres is a >> >> planet, what about the rest of the mass of the asteroid belt? Is it >> >> possible that Ceres is round from getting chipped round by impacts? > >Davoud: >> > ...it doesn't matter because that's not how Ceres got to be a spheroid. >> > It's not as if the mass of Ceres is unknown. (9.5X10E20 kg, or >> > (4.39+-.04)X10E-10 Solar Masses according to some estimates, sufficient >> > to make it spherical.) > >> sufficient. but necessary? > >Yes, a certain minimum mass is required if a celestial body is to be >spherical. the logical condition of "necessary and sufficient" makes for a definition. while the mass to make an object spherical is hardly debateable, that doesn't "necessarily" make it aplanet. > >> this is an arbitrary definition. > >That's right. So what? let's define "cars" as "planets." and let's do it by the body that the world accepts as the "standard bearer." > >> >There is no region in the Universe that is devoid of "controlling mass." > >> right. so a smattering of mass smeared throughout a region is >> meaningless if one object exceeds the arbitrary mass limit? > >You're making stuff up as you go along. I don't see that anywhere in >the IAU proposal. To assert that the other side is claiming something >that it is not doesn't speak well for your skill as a disputant. of course you don't see it. the IAU has disregarded it too. sooo, there is no asteroid belt? just planet ceres and a whole bunch of rocks that share the same orbit? > >> definitions are supposed to be internally consistent. i agree. anyone >> can call anything whatever they'd like. that's not the point. > >> this isn't consistent. its as arbitrary as if i did want to call it >> billy bob. the IAU "democratically" arrives at this "standard." its >> kind of like the old definition of the inch- the distance from the kings >> knuckle to the end of his finger. maybe it worked in the 13th >> century, but it shouldn't be applied now. > >You don't seem to understand that the IAU definition, if adopted, does >not have the force of law. These objects are like all other things that >exist in that you may call them whatever you wish. I don't care what >/you/ call them or whether you like the IAU definition. Why can't you >reciprocate? nobody ever called it a law. if the people that do this stuff come up with a nebulous "definition," is it supposed to mean anything? science speaks with one language, not inconsequential feelings. > >> >Huh? Life is arbitrary. Get used to it. > >> science isn't arbitrary. we're not talking about "life" here. > >This isn't science. There is nothing discoverable about these bodies >that would classify them unequivocally so that no human judgement is >needed, so any definition must be arbitrary. The decision on whether to >call something a tree or a cow is also arbitrary. You do not need to >abide by any of these conventions. You may, if you wish, milk your tree >under the shade of a cow. is that science? > >> >> I disagree with this proposal. not that it matters what I think.. >> > >> >Now you got it. As I said above, the proposal doesn't apply to you. >> >Call these objects whatever you want without reference to what the >> >official designation is and you'll be fine. Take a nap, settle down a >> >bit. it doesn't apply to me. it applies to everyone that wants/needs to speak in the language of particular subject of study. > >> are you a voting member of the IAU panel that's been insulted by my >> not being excited about this goofy proposal? if so, too bad. if not, >> buzz off. > >Are you some egotistical maniac who thinks that anyone cares whether >you are "excited" by this most sensible proposal? If so, too bad. Wake >up and sniff your irrelevance. > >Davoud yo davoud: you're just as irrelevant as everyone else. just cause you like this idea makes you somehow more relevant?             Date: 18 Aug 2006 19:09:18 From: Davoud Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Davoud: > >Yes, a certain minimum mass is required if a celestial body is to be > >spherical. beav: > the logical condition of "necessary and sufficient" makes for a > definition. while the mass to make an object spherical is hardly > debateable, that doesn't "necessarily" make it aplanet. Did you even /read/ the IAU proposal!? If so, read it again, this time for comprehension. Where does it say that all spherical astronomical bodies are "necessarily" planets. To assert that the other side is claiming something that it is not still doesn't speak well for your skill as a disputant. beav: > >> right. so a smattering of mass smeared throughout a region is > >> meaningless if one object exceeds the arbitrary mass limit? Davoud: > >You're making stuff up as you go along. I don't see that anywhere in > >the IAU proposal. To assert that the other side is claiming something > >that it is not doesn't speak well for your skill as a disputant. beav: > sooo, there is no asteroid belt? just planet ceres and a whole > bunch of rocks that share the same orbit? To assert that the other side is claiming something that it is not /still/ doesn't speak well for your skill as a disputant. > >You don't seem to understand that the IAU definition, if adopted, does > >not have the force of law. These objects are like all other things that > >exist in that you may call them whatever you wish. I don't care what > >/you/ call them or whether you like the IAU definition. Why can't you > >reciprocate? > nobody ever called it a law. if the people that do this stuff come up > with a nebulous "definition," is it supposed to mean anything? > science speaks with one language, not inconsequential feelings. Hmmm. Any pun intended with the "nebulous" bit? There is wide agreement in the astronomy community -- I didn't say universal agreement -- that this proposal is quite elegant -- brief, specific, and, like all good science, subject to amendment in the face of new discoveries. > >Are you some egotistical maniac who thinks that anyone cares whether > >you are "excited" by this most sensible proposal? If so, too bad. Wake > >up and sniff your irrelevance. > yo davoud: you're just as irrelevant as everyone else. just cause > you like this idea makes you somehow more relevant? That's right. The difference is that I know it and you seem not to. That's why I'm not arguing for the IAU proposal; I'm arguing for not arguing against it, because the IAU will or will not adopt the proposal without regard to any one else's opposition. I'm more likely to save my energy for a cause where I can influence the outcome, i.e., where I /can/ be relevant. I also assert that if the IAU adopts this proposal you can get used to Ceres, Charon, and UB313 being planets /unless/ you are determined not to accept the idea and are determined to waste your energy railing against the idea. Davoud -- usenet *at* davidillig dawt com               Date: 24 Aug 2006 14:21:54 From: beav Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' if you haven't been keeping up with current events.... this is what is called the "last laugh." HA!         Date: 18 Aug 2006 16:03:48 From: beav Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' On Fri, 18 Aug 2006 16:02:17 GMT, beav <BEAVITH1@NETSCAPE.NET > wrote: >On Thu, 17 Aug 2006 11:40:52 -0400, Davoud <star@sky.net> wrote: > >>beav wrote: >>> A whole lot of discussion about a bad definition. If Ceres is a >>> planet, what about the rest of the mass of the asteroid belt? Is it >>> possible that Ceres is round from getting chipped round by impacts? >> >>Is it /possible/ over the age of the Solar System? I don't know, but it >>doesn't matter because that's not how Ceres got to be a spheroid. It's >>not as if the mass of Ceres is unknown. (9.5X10E20 kg, or >>(4.39+-.04)X10E-10 Solar Masses according to some estimates, sufficient >>to make it spherical.) > > >sufficient. but necessary? > >this is an arbitrary definition. > ><shrug> > > >> >>> or how about it being round because of its fast rotation and the sun >>> subliming ice that gets cold trapped back on the surface? once DAWN >>> gets there, we'll know, but calling Ceres a planet is weird. >> >>If the IAU adopts a definition of "planet" that happens to include >>Ceres, calling Ceres a planet is /ipso/ /facto/ not weird. >> >>> if a region is so devoid of controlling mass (an existing planet), its >>> simply a debris field. >> >>There is no region in the Universe that is devoid of "controlling mass." > > >right. so a smattering of mass smeared throughout a region is >meaningless if one object exceeds the arbitrary mass limit? > >> >>> what if a "planet" ("hydrostatically round >>> object") was parked at one of the lagrangian points ahead or behind a >>> planet? >> >>The definition is suitable to handle that situation. >> >>> just because pluto was the first >>> discovered, and least eccentric member of a disorganized highly >>> eccentric swarm of ice balls, doesn't make it a planet, especially >>> when other members of its class are finally found. >> >>Let's get something clear. The IAO definition does not say that /you/ >>have to call Pluto a planet. You can call it Billy Bob if you want to. >>Other members of its class have already been found, and one of them, >>UB313 ("Xena") will been called a planet under the proposed definition. > > >definitions are supposed to be internally consistent. i agree. anyone >can call anything whatever they'd like. that's not the point. > >this isn't consistent. its as arbitrary as if i did want to call it >billy bob. the IAU "democratically" arrives at this "standard." its >kind of like the old definition of the inch >- the distance from the kings >knuckle to the end of his finger. maybe it worked in the 13th >century, but it shouldn't be applied now. > >> >>> numbering the asteroids is a very workable system. No one is ever >>> going to confuse ceres as a "planet"... >> >>No more confusion. Ceres will be a planet under the proposed definition. >> >>> consider another star system that has multiple asteroid belts and a >>> diffuse KB region. you could have red/brown dwarfs with thousands of >>> "planets," if you use this currently proposed loosening of the current >>> understanding. imagine a blue giant with millions of "planets." >> >>A little too speculative at the moment. Sounds like something the >>proposed definition could deal with if it should arise, however. And if >>it can't deal with the situation, the definition can be changed. >> >>> this idea is silly and absolutely arbitrary. >> >>Huh? Life is arbitrary. Get used to it. > > >science isn't arbitrary. we're not talking about "life" here. > >> >>> I disagree with this proposal. not that it matters what I think.. >> >>Now you got it. As I said above, the proposal doesn't apply to you. >>Call these objects whatever you want without reference to what the >>official designation is and you'll be fine. Take a nap, settle down a >>bit. >> >>Davoud > > >are you a voting member of the IAU panel that's been insulted by my >not being excited about this goofy proposal? if so, too bad. if not, >buzz off.       Date: 18 Aug 2006 03:57:32 From: POA Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Davoud wrote: > beav wrote: > > A whole lot of discussion about a bad definition. If Ceres is a > > planet, what about the rest of the mass of the asteroid belt? Is it > > possible that Ceres is round from getting chipped round by impacts? > > Is it /possible/ over the age of the Solar System? I don't know, but it > doesn't matter because that's not how Ceres got to be a spheroid. It's > not as if the mass of Ceres is unknown. (9.5X10E20 kg, or > (4.39+-.04)X10E-10 Solar Masses according to some estimates, sufficient > to make it spherical.) > > > or how about it being round because of its fast rotation and the sun > > subliming ice that gets cold trapped back on the surface? once DAWN > > gets there, we'll know, but calling Ceres a planet is weird. > > If the IAU adopts a definition of "planet" that happens to include > Ceres, calling Ceres a planet is /ipso/ /facto/ not weird. > /ipso//facto///wrong-o/ > > > if a region is so devoid of controlling mass (an existing planet), its > > simply a debris field. > > There is no region in the Universe that is devoid of "controlling mass." > > > what if a "planet" ("hydrostatically round > > object") was parked at one of the lagrangian points ahead or behind a > > planet? > > The definition is suitable to handle that situation. > > > just because pluto was the first > > discovered, and least eccentric member of a disorganized highly > > eccentric swarm of ice balls, doesn't make it a planet, especially > > when other members of its class are finally found. > > Let's get something clear. The IAO definition does not say that /you/ > have to call Pluto a planet. You can call it Billy Bob if you want to. > Other members of its class have already been found, and one of them, > UB313 ("Xena") will been called a planet under the proposed definition. > > > numbering the asteroids is a very workable system. No one is ever > > going to confuse ceres as a "planet"... > > No more confusion. Ceres will be a planet under the proposed definition. > > > consider another star system that has multiple asteroid belts and a > > diffuse KB region. you could have red/brown dwarfs with thousands of > > "planets," if you use this currently proposed loosening of the current > > understanding. imagine a blue giant with millions of "planets." > > A little too speculative at the moment. Sounds like something the > proposed definition could deal with if it should arise, however. And if > it can't deal with the situation, the definition can be changed. > > > this idea is silly and absolutely arbitrary. > > Huh? Life is arbitrary. Get used to it. > > > I disagree with this proposal. not that it matters what I think.. > > Now you got it. As I said above, the proposal doesn't apply to you. > Call these objects whatever you want without reference to what the > official designation is and you'll be fine. Take a nap, settle down a > bit. > > Davoud > > -- > usenet *at* davidillig dawt com         Date: 18 Aug 2006 10:08:03 From: Davoud Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Davoud wrote: > > If the IAU adopts a definition of "planet" that happens to include > > Ceres, calling Ceres a planet is /ipso/ /facto/ not weird. POA wrote: > /ipso//facto///wrong-o/ What I wrote was another way of saying that /ipso/ /facto/ it cannot be /wrong/ -- for IAU members and others who adhere to IAU naming conventions -- if adopted. So what's your problem!? If Ceres as a planet is wrong /for/ /you/ , call it whatever you want, and no one will care. /You/ aren't required to adhere to the definitions of the IAU. But don't presume to tell anyone else what is right or wrong /for/ /them/ . Davoud -- usenet *at* davidillig dawt com   Date: 17 Aug 2006 11:02:06 From: oriel36 Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' This group of seven convened in Paris in late June and > 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." Is there some prize among these people for stating the complete opposite of what should be stated. In trying to define something they have little know of,terrestially and astronomically,they shut off the ability to consider the rotational dynamics of a rotating molten and flexible interior.The Earth's deviation from a perfect sphere is a continuing dynamic of the molten\flexible interior specifically latitude dependent differential rotation. Nothing is in equilibrium,the mechanism for the planet's shape is also the same mechanism which causes the plates of the fractured crust to move and collide.Of course the hydrostatic equilibrium is needed to support the infantile stationary Earth\convection cells mechanism for crustal motion and shunting the Earth's shape into the realm of an evoilutionary artifact. What did humanity do to deserve this,after all the works of brilliant men from generation after generation to see these pathetic creatures try to 'define' a planet for the rest of humanity.Of course with empiricists running astronomy,it could not be any other way. Anyone feel disgusted enough yet !. > Owen Gingerich, the Chair of the Planet Definition Committee says: "In > July we had vigorous discussions of both the scientific and the > cultural/historical issues, and on the second morning several members > admitted that they had not slept well, worrying that we would not be > able to reach a consensus. But by the end of a long day, the miracle > had > happened: we had reached a unanimous agreement."     Date: From: Subject:   Date: 18 Aug 2006 01:48:26 From: Dan Tilque Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' baalke@earthlink.net wrote: > > The world's astronomers, under the auspices of the > International Astronomical Union (IAU), have concluded two > years of work defining the difference between "planets" and > the smaller "solar system bodies" such as comets and > asteroids. Just think: if Clyde Tombaugh (or anyone else, for that matter) had discovered even one more KBO during the 30s or 40s, this whole exercise probably would have been unnecessary. If they'd discovered two more KBOs, it definitely would have been unnecessary. -- Dan Tilque     Date: 18 Aug 2006 15:53:46 From: beav Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' On Fri, 18 Aug 2006 01:48:26 -0700, "Dan Tilque" <dtilque@nwlink.com > wrote: >baalke@earthlink.net wrote: > >> >> The world's astronomers, under the auspices of the >> International Astronomical Union (IAU), have concluded two >> years of work defining the difference between "planets" and >> the smaller "solar system bodies" such as comets and >> asteroids. > >Just think: if Clyde Tombaugh (or anyone else, for that matter) >had discovered even one more KBO during the 30s or 40s, this >whole exercise probably would have been unnecessary. If they'd >discovered two more KBOs, it definitely would have been >unnecessary. exactly. the technology of the era (or lack thereof) shouldn't be the reason for having this discussion.   Date: 18 Aug 2006 21:40:24 From: Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' Greg Crinklaw wrote: > Hi Mark, > > I agree. I think your comments are very insightful and your reasoning > sound. There can be no reasonable scientific definition of "planet." You know, on further consideration, I think their definition is a brilliant bait-and-switch. Right now, everybody thinks that Pluto is retaining planetary status. But notice they have casually introduced the term "classical planet" for the biggest eight. As the number of planets multiplies, people will start to shorten "classical planet" to "planet", and group Pluto with the other clutter, and eventually Pluto will have lost its status without the IAU ever having said so. So maybe this definition isn't so bad. . . .     Date: From: Subject:     Date: 18 Aug 2006 23:40:45 From: Thomas Lee Elifritz Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' mark.foskey@gmail.com wrote: > Greg Crinklaw wrote: >> Hi Mark, >> >> I agree. I think your comments are very insightful and your reasoning >> sound. There can be no reasonable scientific definition of "planet." > > You know, on further consideration, I think their definition is a > brilliant bait-and-switch. Right now, everybody thinks that Pluto is > retaining planetary status. But notice they have casually introduced > the term "classical planet" for the biggest eight. As the number of > planets multiplies, people will start to shorten "classical planet" to > "planet", and group Pluto with the other clutter, and eventually Pluto > will have lost its status without the IAU ever having said so. > > So maybe this definition isn't so bad. . . . Except for Ceres, the inconvenient planet. But that makes nine. http://cosmic.lifeform.org   Date: 18 Aug 2006 15:11:02 From: Double-A Subject: Re: The IAU Draft Definition of 'Planet' and 'Plutons' osdfey wrote: > On Fri, 18 Aug 2006 13:21:24 -0600, Greg Crinklaw wrote: > > > Hi Mark, > > > > I agree. I think your comments are very insightful and your reasoning > > sound. There can be no reasonable scientific definition of "planet." > > > > There are so many practical problems the proposed solution would cause. > > Off the top of my head it would: > > > > * complicate teaching kids about the solar system > > oh well > > > > > * add minor objects to what is supposed to be, by definition, a list of > > major bodies > > not by the new definition, oh well > > > > * make it difficult to organize astronomy texts and lectures > > > > oh well > > > * create embarrassing ongoing debates about new bod