new planet definition proposal

[cp28]

Saw this over on cnn and the main page here. Guess this is right spot?? :/<br /><br />What do people think of this?<br /><br />Basically any round object of a certain size that orbits the sun would be classified as a planet is the best I can state.<br /><br />http://space.com/scienceastronomy/060816_planet_definition.html<br /><br />The initial new planets- <br /><br /> * The asteroid Ceres, which is round, would be recast as a dwarf planet in the new scheme.<br /><br /> * Pluto would remain a planet and its moon Charon would be reclassified as a planet. Both would be called "plutons," however, to distinguish them from the eight "classical" planets.<br /><br /> * A far-out Pluto-sized object known as 2003 UB313 would also be called a pluton.<br />-----------------------------------<br /><br />Draft resolution here<br />http://www.space.com/scienceastronomy/060816_planet_resolution.html<br /><br />

 

[robnissen]

It is RIDICULOUS that Charon is a planet. The rest of the definition I can live with, although it strikes me that we might end up with 100s of planets, just to come up with a definition that keeps Pluto a planet. But a moon should not be a planet.

 

[bdewoody]

I agree, if Charon is a planet then why not all of the larger moons of Jupiter and Saturn? <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[harmonicaman]

...and Ceres???<br /><br />That's an ASTEROID!

 

[jmilsom]

It makes sense though, compared to its parent, Charon is much larger than an ordinary moon. Pluto and Charon could almost be described as Binary Planets. <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

The explanation they give is that since both Pluto and Charon revolve around a point that is between them (not below the surface of Pluto) it is a double planet.<br />I still have to ponder that a bit, but it kind of makes sense.<br />All the other satellites (including the earth's moon) revolve around a point inside the planet.<br />Since Pluto and Charon are so close in mass, that point (the barycenter) is in space.<br /><br />MW <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[cuddlyrocket]

Ceres is no longer an asteroid. (Historically, it was classified as a planet when it was first discovered, and then subsequently downgraded after the asteroids were discovered.) It is different from the asteroids in that it is in hydrostatic equilibrium (its shape is dominated by gravitational forces so it assumes a spherical shape).<br /><br />The large moons of Jupiter, Saturn etc are not planets as they are satellites of Jupiter, Saturn etc. Charon is not a satellite of Pluto - the two objects are in mutual orbit <i>around each other</i>.<br /><br />That's the rationale. You're welcome to disagree with it, of course.<br /><br />'Dwarf planet' is not a term recognised by the IAU as a formal definition (nor are 'gas giants' or 'terrestrial planets' for that matter). It is simply a convenient term suggested for planets smaller than Mercury. Similarly, the term 'classical planet' is suggested for the planets Mercury sized and bigger within the Solar System.<br /><br />The IAU press release is here.

 

[eosophobiac]

<i>Since Pluto and Charon are so close in mass, that point (the barycenter) is in space.</i><br /><br />You've cleared up one of my misgivings WRT this whole 'planet definition' thing. I was a bit lost about why they would've classified Pluto and Charon as such, but now that I've read this, I can sort of see why they'd do it that way.<br /><br />*<b>un</b>certainly decided* (or is it: certainly <b>un</b>decided..?) <img src="/images/icons/crazy.gif" /><br /> <br /><br /> <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[ittiz]

I like the new definition it's just about what I thought it should be. Charon is a planet because the barycenter of Pluto and Charon is outside both of them. So they are now known as a double planet. That is why things like Titan and the moon won't be.

 

[auraboyx]

I feel the need to throw in my two cents on this whole topic. I would say I have more than just a passing interest in science and technology. I am by no means a pseudo-scientist or even a hard-core astronomer. I read my Discover magazine and Popular Science, keep up to date with all things science related on-line as well as catching any good science documentaries that may pop up on PBS from time to time. I am confident in classifying myself as an ordinary person with a love for science.<br /><br />With that said I think the new planet classification system is great. The rules seem simple enough to me (as a layman) and it astounds me when people say it may be confusing for the general public. I think some people are making this new system more confusing than it is. The rules are straightforward and anyone with a passing love for space/science will be able to understand them easily. The public who doesn’t ‘get it’ really has no interest to begin with and shouldn’t be factored into the equation.<br /><br />Even though there is no formal definition of a planet I feel that if you were to take a random sampling of people off the street, sit them down in a room and show them illustrations of the following (non-labeled) celestial objects on flashcards, then ask them to state yes or no if what was on the flashcard was a planet or not, it would probably (9 out of 10 times) go like this:<br /><br />Vesta – “No”<br />Sedna – “Yes”<br />Jupiter – “Yes”<br />The Sun – “No”<br />Eros – “No”<br />Halley’s Comet – “No”<br />Europa (with Jupiter in background) – “No”<br />Earth – “Yes”<br />Ida – “No”<br />The Voyager Spacecraft – “No”<br />Pluto – “Yes”<br />The Moon (so long as it was a familiar photograph) – “No”<br />Europa (with NO Jupiter in background) – “Yes”<br />A perfectly round cantaloupe floating in space – “Yes”<br /><br />The point to all this is the definition of a planet is imbedded into our psyche. A giant sphere floating in space (unless it is in flames or understood as a moon) is a p

 

[alokmohan]

Book publishers are impressed,they can earn a lot.

 

[qso1]

Considering the astronomical knowledge I've seen on the streets...I'd say the list would look more like this, LOL:<br /><br />Vesta – “Huh” <br />Sedna – “Huh” <br />Jupiter – “Yes” <br />The Sun – “No” <br />Eros – “Thats something in an "X" rated book store isn't it” <br />Halley’s Comet – “No” <br />Europa (with Jupiter in background) – “Which ones the planet” <br />Earth – “A planet but its flat” <br />Ida – “Ida what” <br />The Voyager Spacecraft – “Vger” <br />Pluto – “The dog or the planet” <br />The Moon (so long as it was a familiar photograph) – “No” <br />Europa (with NO Jupiter in background) – “This was faked” <br />A perfectly round cantaloupe floating in space – “Now thats a planet but I can't quite put my finger on which one it is”<br /><br />BTW, welcome to SDC, good posting. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[auraboyx]

Very funny! LOL... But I said NON-Labeled pictures... <img src="/images/icons/blush.gif" />

 

[qso1]

Don't take offense, I was joking, sorry.<br /><br />I should have said your posting was seriously a good one because I did understand what you were getting at. I just wanted to make social commentary because in fact. Most people on the street I know don't know squat about astronomy or space travel. They know more about what Britney Spears feeds her baby than they do which planets are planets and so on. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[cuddlyrocket]

A few astronomers have come up with an alternative proposal (which you can find in full in this space.com article).<br /><br />This comes from the 'Pluto <i>is not</i> a planet crowd'. (Astronomers seem to be divided into three groups. The afore-mentioned crowd, the 'Pluto <i>is</i> a planet crowd', and the much bigger 'We don't care either way, but we want the argument over crowd'!)<br /><br />The main differences with the IAU one is that it adds the criterion 'is by far the largest object in its local population' (by local population they mean 'the collection of objects that cross or close approach the orbit of the body in consideration'). However, they remove the 'orbit a star' and the 'not a satellite of a planet' criteria.<br /><br />(They also deal with the upper limit by a 'no nuclear fusion' criterion.)<br /><br />They then define 'dwarf planets' as objects that satisfy the round by gravity and no nuclear fusion criterion definition.<br /><br />This seems a much worse definition to me. For one thing it increases the vagueness a lot. What do they mean by 'by far', by 'collection' and by 'close approach'. For instance they say that by their definition Ceres is not a planet, presumably because they think the difference in size between it and the next (although clear and significant) is not 'by far'. If we discovered a solar system that had two bodies the size of Earth and Venus orbiting each other whilst going round their star, neither of these would be a planet by this definition and interpretation of 'by far'.<br /><br />Then, according to this definition, Pluto and Ceres are not planets, but <i>are</i> dwarf planets. Generally descriptors such as 'dwarf' (and 'terrrestrial' and 'rocky') are used to sub-divide a category, not to differentiate categories entirely.<br /><br />Generally, this seems to bring in more problems than it removes (all in trying to make a definition that excludes P

 

[alokmohan]

Britnety spears--planet,moon or KBO?

 

[harmonicaman]

Finally! Logical heads seem to be prevailing on the IAU and it looks like this dumb proposal won't be approved in its original form.<br /><br />Who want's to see our Moon become designated as a planet? It will eventually meet all the criterea...<img src="/images/icons/rolleyes.gif" /><br /><br />Planets should be a special designation; every ice ball shouldn't get that title and we should have to revise the number every few years.<br /><br />Neither the original proposal nor the revision would likely be applicable to all Extrasolar planetary systems; there are certainly going to be systems that are just too alien to fit into a simple classification system -- this is "Bodes Law" kind of thinking. <br /><br />I really like that the new proposal keeps the planet designation only for the largest and most significant members of Solar Systems; the original plan was just too revisionist -- not everything under the Sun needs to be called a planet.

 

[Philotas]

If the moon turn out to be a planet in several billion years, so what? There is nothing wrong in viewing the Earth and the Moon as a double planet when the barycenter moves above the Earths surface; how else do you want to define double planets?<br /><br /><br /><font color="yellow">Planets should be a special designation; every ice ball shouldn't get that title and we should have to revise the number every few years.</font><br /><br /><br />We shouldn't make definitoins after desire! Let's just make an easy definiton that allows quick catergorizing of new found objects, instead of having to strive with bureacracy years after the discovery of the actual object(does it reside in a "belt" of similar sized objects, or does it not?). <div class="Discussion_UserSignature"> </div>

 

[Philotas]

I completely agree. Couldn't agree more. <img src="/images/icons/laugh.gif" /> Those are the words I've been preahing since I got engaged in this debate. (put simple) A planet is just a circular shaped space rock! <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

KBOs are hanging plenty and we may keep on discovering.The painful system of nomenclture by assigning a number cryptic code should be dispensed with.Same for asteroids.To get name you are to wait for years.Why cant they make it simple .Burearocracy should go.

 

[harmonicaman]

<b>Alokmohan --</b><br /><br /><i>"The painful system of nomenclature by assigning a number cryptic code should be dispensed with. Same for asteroids. To get name you are to wait for years. Why cant they make it simple .Bureaucracy should go."</i><br /><br />I agree that the numbering system is cumbersome, but newly discovered objects need some kind of internationally accepted identity so they can be carefully examined to determine exactly what they are. <br /><br />The wait for an official name to become official is due to many reasons, including:<br /><br />1. To avoid repetition.<br /><br />2. To make sure the name fits into the pattern of previously accepted naming parameters for similar objects.<br /><br />3. To make sure the name is internationally acceptable. <br /><br />I agree that the bureaucracy is a pain...

 

[MeteorWayne]

KBO; Kid Brewing Organism <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[rhm3]

<blockquote><font class="small">In reply to:</font><hr /><p>Neither the original proposal nor the revision would likely be applicable to all Extrasolar planetary systems; there are certainly going to be systems that are just too alien to fit into a simple classification system -- this is "Bodes Law" kind of thinking. <br /><br />I really like that the new proposal keeps the planet designation only for the largest and most significant members of Solar Systems; the original plan was just too revisionist -- not everything under the Sun needs to be called a planet. <p><hr /></p></p></blockquote><br /><br />Aside from the "pluton" junk, I think the first definition is the most applicable one can get for other stellar systems. Large enough to gravitationally become round, too small to fuse, orbits a star. Simple. Once it's determined an object orbits a star, all that has to be confirmed is size (and shape if its between 400-1000km or so).<br /><br />Adding in orbital dominance as a criteria opens the door for many more arbitrary limits and cutoffs. What constitutes orbital dominance? 70% orbital mass? 80%? How spread out can a belt get while still remaining a belt? Realize the Kuiper Belt is wider than the distance between Mercury and Neptune...<br /><br />While I'm on the subject, is Sedna a planet? Right now it's not known to share its orbit with other bodies, so technically it qualifies as a planet. Sure, there may be other objects near it but we don't know that for sure now. So what do we do? <br /><br />Orbital dominance criteria also means more demotions. Let's say we find an object by itself and it's classified a planet. Then some time later, other objects are found and it's considered to be in a "belt" and not a planet. Pluto redux...and I rather not go through this kind of debate again. <br /><br />Yet another issue...with very small systems now being discovered, it is not a stretch to believe there could be an "orbitally dominant" Ceres-sized object out there. If that's the case, then

 

[rhm3]

Auraboy, you've illustrated a point I've been trying to say all along. Well done. <br /><br />BTW you brought up your nephews getting excited about more planets. I saw my 4-year old cousin today who happens to love planets...for example she knows the "9" planets in order and what they look like. I asked her if she knew about the new planets and she said with excitement "YEAH I wonder what they'll be named!!" She also said "and some of them are even COLDER than Pluto!!" I told her the total could pass 20 and her eyes widened a bit LOL. <br /><br />The point is, kids will be excited by new planets. I doubt the same could be said if Pluto was demoted. I, too, view this to be a huge plus. Not to mention it has huge scientific and simplicity advantages as has already been outlined in this thread.

 

[earthseed]

Are you in touch with your Inner Planet?<br /><br />The kids may get excited about a few new planets, but attention may drift off when the new planets start numbering in the dozens and hundreds, and more get discovered every other week. I suggest we refer to the eight planets as "inner planets", and we can call the Kuiper Belt Objects "outer planets" to improve their status. And rather than demoting Pluto, we can promote it to the head of the outer planets, on the basis of seniority (and closeness to the sun) if not by size. This way everyone wins, and we can all feel good about all our planetary neighbors.<br /><br />Except for Ceres. Ceres a planet? Get Sirius!