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Press coverage

The IAU meeting is underway, and press coverage is beginning. Here is an article I've encountered (Associated Press, at the website for the Boston Globe): http://www.boston.com/news/science/articles/2006/08/14/astronomers_meet_to_define_planet/. GRBerry 21:19, 14 August 2006 (UTC)[reply]

Twelve Planets

The number of planets may need to be expanded to twelve following the news that the International Astronomical Union has recommended to its members that Charon, Xena and Ceres be ratified as new planets. [1] The new definition states that a planet is any star-orbiting object so large that its own gravity pulls in its rough edges, producing a near-perfect sphere. Terjepetersen 06:30, 16 August 2006 (UTC)[reply]

What the heck? How does this work? OK. Any round object over 800 km is a planet. Fine. But according to that definition there should be at least 30 planets; not 12. Why are Pluto and ub313 added, but not Quaoar or Sedna? Why is Charon addded, but not the Moon? Both co-orbit the Sun. Why is Ceres added, but not Vesta? Serendipodous 06:25, 16 August 2006 (UTC)[reply]
Perhaps there is some variability on how strictly they want to define "round". Even Earth has mountains. As for Charon, it might not qualify as a moon because it is too large relative to the planet it orbits. Algr
I just heard Mike Brown on the radio. He says that it is likely that the current count of 12 will be increased as we determine the precise dimensions of recently discovered objects. 12 could become a hundred before too long. By the end of the 21st century it could become a million. Serendipodous 07:40, 16 August 2006 (UTC)[reply]
Yeah, we don't know as much about Quaoar and Sedna. We suspect they probably fit under the roundness definition, but we don't have enough data yet. Charon was added because the barycenter of the pluto-charon system is outside the surface of either planet. Therefore, neither is a satelite of the other, but it would be considered a dual-planet system. The moon is clearly a satelite of the earth. Ceres is added because ceres is large enough to make it's shape stable due to its own gravity. Vesta has an irregular shape, therefore its gravity isn't enough to give it a stable shape. Any other questions? McKay 13:44, 16 August 2006 (UTC)[reply]
Actually, Vesta is technically spheroidal. We have enough data on most of the "Plutons" to make a fairly definitive statement on how round they are. Sedna may be far away, but it's not as far away as Xena (not at the moment, anyway), so if we know Xena's round, I'm pretty sure we can figure out if Sedna is. Serendipodous 14:36, 16 August 2006 (UTC)[reply]
No, 4 Vesta is not spherical spheroidal. Yes, I think they will quickly add Sedna to the list. McKay 15:18, 16 August 2006 (UTC)[reply]

Vesta

I didn't say it was spherical. I said it was spheroidal. Read the subsection on sphericity. Your picture is right there. Serendipodous 15:47, 16 August 2006 (UTC)[reply]
The picture shows that vesta isn't spheroidal. Note the knob in the bottom center. This "cross section" clearly is not an ellipse, therefore, not spheroidal. This also shows that it isn't even an ellipsoid. McKay 15:51, 16 August 2006 (UTC)[reply]
Also note the shading on the front center that hints to the fact that there is another knob on the "front". McKay 15:53, 16 August 2006 (UTC)[reply]
Believe me, Mckay, I've had this argument before, and argued your side. Just look at the second archive; it's nothing but. It's perfectly possible for someone to claim that Vesta is a spheroid; if it wasn't then I would have changed that table long ago. Serendipodous 15:56, 16 August 2006 (UTC)[reply]
okay, I've been through that page, and I don't see anything (maybe I missed it) that shows that Vesta is a spheroid. I can see how it's gravity almost makes it a spheroid, but I don't think that that's enough for the IUA's distinctions. So, I can see how someone could say that it is a spheroid, because it's kinda close, but the same case could be made arguing that it isn't spheroidical, which is the claim that I'm making that I think is valid. McKay 16:04, 16 August 2006 (UTC)[reply]
They managed to boot Pluto out (hurray!) by allowing so many dumb rocks to be included, in a while nobody will care anymore. We'll go to a sensible list of 8 (major) planets, and a large number of dwarf planets. Bet you pretty soon planet will come to mean major planet, and therefore: 8 planets in the solar system. -- Jordi·✆ 13:53, 16 August 2006 (UTC)[reply]
"Dwarf planet" is to be an unofficial definition. Officially, all classical and dwarf planets and plutons would be planets.--JyriL talk 13:56, 16 August 2006 (UTC)[reply]
Of course. But I severely doubt the majority of these will be considered real planets by the majority. There may be twelve planets thursday, 24 before long (3 asteroids and at least 8 KOBs are large and round enough to be included), and once we discover more rocks out in the Kuiper Belt, dozens or even hundreds in a few years. With the handy unofficial (but defined by an official body) term "dwarf planet" they've given us a great cutoff point which just happens to only include the classical planets, and excludes the subject Pluto and its kin. -- Jordi·✆ 14:07, 16 August 2006 (UTC)[reply]
  • that's your imagination at work, i'm happy with these twelve:
Ceres: "the little rocky planet", with a lot of debris around.
Pluto and Charon: a pair of planets orbiting each other.
UB313: the new outer planet.

the problem are those KBO's around, they need some more criteria such as minimum mass.

Plus, asteroids lost status.

See this simulation with the 3 new planets: http://www.newscientist.com/data/images/ns/av/dn9761V1.mpeg

Mass of UB313: ?! (planet)
Mass of Pluto: 1.305×10^22 (planet)
Mass of Charon: 1.52 ×10^21 (planet)
Mass of Ceres: 9.5×10^20 (planet)
Mass of Orcus: 6.2 - 7.0×10^20 (not a planet)

So anything that is round and has more mass than Ceres?--Pedro 14:36, 16 August 2006 (UTC)[reply]

That definition seems pretty arbitrary. If they're going to randomly cut off the mass limit at Ceres, why not Pluto? Or Mercury? Serendipodous 14:58, 16 August 2006 (UTC)[reply]
Yes, it it like the "Dwarf planet". Why Ceres is a Dwarf and not the Earth? --Pedro 15:02, 16 August 2006 (UTC)[reply]
Likely because the current definition of dwarf planet neatly includes all 8 classical planets, and excludes the problematic Pluto. Any other definition will be harder to sell to the public en large. -- Jordi·✆ 15:10, 16 August 2006 (UTC)[reply]
  • I doubt it, people just dont know how these objects look like. If they see a picture of it, they will consider it a planet. How can you say Jupiter (a huge ball of gas) is a planet and Pluto (with a surface) is not. I don't understand your criteria. We are in the 21st centuy, probles explored these objects. --Pedro 15:21, 16 August 2006 (UTC)[reply]
    They're not "my" criteria ;)
    I can understand the rationale behind them, though. The line must be drawn somewhere: the new definitions allow for just about every roughly round rock not a moon to be a planet. We have 12 now, and hundreds before long. Arbitrarily giving Mercury's mass as a minimum not only neatly avoids all the small ones, but also is identical to the list of planets before Pluto was mistakenly added. (I call it a mistake, just as adding Ceres and the other asteroids was seen as a mistake in the 1850s: Ceres used to be a planet.) -- Jordi·✆ 15:26, 16 August 2006 (UTC)[reply]
I'm pretty sure that it has nothing to do with Ceres, it's just that Ceres has enough mass to be a spheroid on it's own right. McKay 15:39, 16 August 2006 (UTC)[reply]
  • Chinese and Indians are still humans despite you can count billions of them, they have the same human rights has you. One just needs to accept the solar system is not as ordered we used to think, we have pictures and we know they are very different, we have better telescopes, etc. There's no reason to exclud Pluto and others from Planethood. People will like to know there's a tiny planet within the asteroid belt, Ceres, it will make them wonder.--Pedro 15:41, 16 August 2006 (UTC)[reply]
Exactly -- it's far more exciting to discover new planets. Very few people care nearly as much (if at all) about extra Trans-Neptunian Objects. The most significant outcome of this debate, IMHO, is that it raises public awareness and excitement about astronomy. --TiroAethra 16:00, 16 August 2006 (UTC)[reply]
Pedro, are you accusing us Earthlings of being planetist? Serendipodous 15:52, 16 August 2006 (UTC)[reply]
I believe the correct term is "Jovians." Most inhabitants of Jupiter would consider your word for them a racial slur. Serendipodous 16:04, 16 August 2006 (UTC)[reply]
Silly Americites :D McKay 16:06, 16 August 2006 (UTC)[reply]

Orbital period of the moon and the planet

The current article contains a paragraph that describes how any moon-planet system may be considered a double-planet. The paragraph goes on to say that "The required distance from the planet to the moon depends on the mass of the planet, and the distance from the planet to the Sun, but not the mass of the moon. If the distance from the Sun to the planet increases, or the planet's mass decreases, then the required distance between the planet and moon increases."

I disagree with the statement that the mass of the moon does not change the required distance. I also disagree with the statement that as the planet's mass decreases, the required distance to the moon increases.

The period of orbit of one body about another depends upon the mass of both bodies, as this is what determines the gravitational force between the two bodies. However, as a first approximation, the mass of the smaller body is usually considered to be small when compared to the mass of the larger, and hence the orbital period calculation, in this instance, can be said to depend only on the mass of the larger body. This is usually the case in Earth's solar system, although since the article is attempting to be general and apply to any system of orbiting bodies, the approximation may not hold true in all circumstances.

On the second point, even if we assume that the mass of the moon is small, then as the mass of the planet decreases, the gravitational force between it and the moon will also decrease. Hence, the period of the moon at that orbital distance will lengthen. Therefore, the moon could orbit at a closer orbital distance and still have an orbital speed slower than the planet's speed around the star. Therefore, the required distance between the moon and planet decreases (the article as it is written says "increases").

There is no reference for the statement in the article but the article has apparently been peer reviewed so I assume someone has checked this out, and I am interested is reading what that person(s) has to write, as I am open to a complete discussion of the dyanamics of orbiting bodies and may learn something on my part. I did not make any changes to the main article for the same reason.

D. Clippinger

I'd be interested to see this issue resolved. I've been meaning to source that paragraph for a long time (for the record: I didn't write it) but lack the knowledge of Newtonian dynamics to do so. Serendipodous 19:08, 16 August 2006 (UTC)[reply]
Drat, this means that I have to break out my physics book and figure it out. Could someone get me a reference of who added that particular change while I'm doing the math? McKay 20:31, 16 August 2006 (UTC)[reply]
His name was Tompw. Serendipodous 08:38, 17 August 2006 (UTC)[reply]

Merge of 2006 redefinition of planet

Since we already have a (featured) article on the Definition of planet, I do not see why the 2006 redefinition needs its own article. As soon as the media frenzy is over, I suggest that the latter be merged into the existing article. Nick Mks 10:25, 17 August 2006 (UTC)[reply]

  • Good idea. I've already had to revert a tag removal though, after someone found himself important enough to decide by himself that this needs a seperate article. Nick Mks 14:38, 17 August 2006 (UTC)[reply]
  • Wow, we don't have an article on the discovery of Pluto? That's a travesty. It should be created as a sub-article of Pluto and fully fleshed out. There's more than enough verifiable information on the discovery of Pluto to create a featured article. --Cyde Weys 17:08, 17 August 2006 (UTC)[reply]
  • What about Herschel's discovery of Uranus? That was a far more revelatory moment; no one even suspected that there could be a new planet in our system when he found it. And what about the kerfuffle over Neptune? 17:23, 17 August 2006 (UTC) — Preceding unsigned comment added by Serendipodous (talk • contribs)
  • Exactly the point. No one suspected new planets, so the discovery events don't have as much information / hype. They were searching for Pluto for years, and there's lots of people who tried (including PL). There's a bunch of content available on the discovery of pluto. McKay 18:37, 17 August 2006 (UTC)[reply]
  • I am familiar with WP:Point I really do think that pluto has enough information to have an article on it's discovery. The pluto article is currently too large, and look at these stats -- Google hits:
  • "discovery of pluto" OR "discovering pluto" OR "discovered pluto" 70,100
  • neptune 38,200
  • uranus 34,400
the discovery of pluto is more notable if you ask me. McKay 20:40, 17 August 2006 (UTC)[reply]
  • Of course we're serious. You don't think the discovery of a fucking planet is notable enough for its own article? Christ! That AFD would be closed in record time. And please don't go throwing around WP:POINT accusations; that doesn't even make any sense in this instance. --Cyde Weys 21:02, 17 August 2006 (UTC)[reply]
Hey hey hey hey. Don't do that.  -- Run!  07:20, 18 August 2006 (UTC)[reply]
  • Merge now. This is the page for tracking the goings-on with the IAU. The new article will be hard to find unless it is prominently link to through this page. --EMS | Talk 16:16, 17 August 2006 (UTC)[reply]
  • Merge now. The two different pages are saying the same thing in different ways - it's annoying. The Singing Badger 17:35, 17 August 2006 (UTC)[reply]
  • Merge after. It isn't August 24, so I don't see how we know if the proposed defintion actually will be the ultimate one. If the decision is different from the current article, and it's merged now, then the information will not have just been incorrent then, but for almost 2 whole weeks. Radagast83 18:48, 17 August 2006 (UTC)[reply]

Image:Newplanets.jpg

At Talk:2006 redefinition of planet#Image removal rationale, concerns have been brought up regarding the use of Image:Newplanets.jpg. I'd like to know what the general opinion here is. I personally would remove the image for the reasons given on the above page. Nick Mks 19:19, 17 August 2006 (UTC)[reply]

It's inaccurate. The new ruling by the IAU wouldn't establish nearly the number of planets as that image is claiming. Plus, it's too busy, and frankly, it's ugly. Accuracy issues aside, there has to be a much better and prettier way to show those orbits. --Cyde Weys 19:21, 17 August 2006 (UTC)[reply]

Well, as the person who imported that image I should justify my action at least. There has been a great deal of supposition and fudging released by the IAU in the last few days that has been picked up by the media as established fact; the most notable being, of course, that there are now 12 planets. This is wrong. There could be (and indeed should be, if the definition were to be scientific rather than cultural) dozens of planets in our solar system. That image demonstrates a fixed, scientific limit for the total number of planets in our system. Anything below it would have to be justified in some way other than, "But that's just too many!" Serendipodous 19:49, 17 August 2006 (UTC)[reply]
I think the image is great. Sure, it's a little rough, but I think it's cool. The rationale for the 12 planets is that those are the ones we have relative certainty of their Hydrostatic equilibrium. The other 53-12=41 Mike Brown thinks are probably round enough, but we don't have enough information. More information will most likely bring the number to around 53 quickly, and several hundred (thousand) in the future. McKay 20:40, 17 August 2006 (UTC)[reply]

Periodicity

Hello anon user. While I admire your dedication to truth, there are several rules involved, particularly WP:NOT. I would imagine that 1 Ceres.com is your page. I'm not sure how I feel about your opinions from a mathematical sense, it doesn't seem right, but it might be true. There does appear to be some credence to your claims. Alas, Wikipedia isn't as interested in Truth, as it is in Verifiability. I'm not here to say that the claim is false, but I'm saying that it isn't verifiable. When 1ceres.com gets reviewed by a major journal or website, it will go in, even if unproven, because Verifiabiliy is more important to Wikipedia than truth.

On a seperate note, reverting a revert, especially without reasoning, is considered bad form. McKay 04:10, 18 August 2006 (UTC)[reply]


Should the following information be included within the definition? See the discussion about the Titius-Bode for the actual equation.

The Periodicity of Planets Recently, a new periodicity of planets was developed by Tyler Granger from the Titius-Bode Law that demonstrates a recognizable accuracy[1]. Because of this periodicity, planets are defined by a natural phenomena rather than an institution. This new equation was discovered in the late 1990's prior to the discovery of 2003_UB313 (Xena). The discovery of this periodicity has yet to be accepted by the IAU. Yet, the redefinition of 1Ceres and 2003_UB313 would bring the planets of the Solar System into compliance with the periodicity[2].

Yes or no? Fact or rule breaker? — Preceding unsigned comment added by PlanetCeres (talk • contribs)

Nothing was deleted from Talk:Titius-Bode law in the last 24 hours. Nick Mks 09:41, 18 August 2006 (UTC)[reply]
Quite simply, this is a rule breaker because it is original research. If it ever gets accepted in a peer-reviewed science journal like Nature or Science, then yes, it would be worthy of inclusion. Until then, no. Serendipodous 14:13, 18 August 2006 (UTC)[reply]

Definition of moon aka "satellite"

from IAU:

Q: What is a “satellite” of a planet?
A: For a body that is large enough (massive enough) to satisfy the definition of “planet”, an object in orbit around the planet is called a “satellite” of the planet if the point that represents their common centre of gravity (called the “barycentre”) is located inside the surface of the planet.
As I read it, all satellites are still satellites even if they are large enough to be planets. But I agree, that is a bit ambiguous. Serendipodous 14:13, 18 August 2006 (UTC)[reply]

Maybe the solution is more simple: they could define just two types of objects: stars (objects that sustain or have sustained some form of fusion) and planets (I would discard the term "satellite"). Then we could speak only about systems: a system is a "stellar system" if the more "representative" (normally, the more massive) object in it is a star; and a system is a "planetary system" if the more representative object in it is a planet. So, Ganimedes is a planet in the planetary system of Jupiter, which in turn is in the Sun solar system. Is there a fundamental flaw in this? I see the other definitions too arbitrary.Damien,18-08-2006.

PSR B1257+12D

You know, with the proposed redefinition of planet, PSR B1257+12 D is bigger than Ceres, so would be a planet, so this proposal is already having an impact on extrasolar planets. 132.205.45.148 04:26, 19 August 2006 (UTC)[reply]

The mass value for PSR B1257+12 "D" is an upper limit based on the non-detection of gravitational effects... it could easily be much smaller. I'd hold off on claiming planethood. If the object exists, it has been detected via cometary activity (the object's coma affects the transmission of the pulsar's emissions). Chaos syndrome 10:12, 19 August 2006 (UTC)[reply]
  1. ^ Tyler Granger (2002). "Discovery of Planetary Periodicity". 1Ceres. Retrieved 2006-08-17.
  2. ^ Tyler Granger (2003). "Further Exploration of a New Bode Periodicity". 1Ceres. Retrieved 2006-08-17.
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