Official Declaration of Planetary Status

Spacemad · #1 (**permalink**) 02-October-2005, 10:29 PM

Here is the OFFICIAL declaration of what makes a planet a planet or some other kind of object:

Space panel decides on the definition of planet

http://www.arcamax.com/cgi-bin/news/...7/33131/916030

Manchurian Taikonaut · #2 (**permalink**) 02-October-2005, 10:36 PM

the recent ones & pluto can be called KBOs then ?

Spacemad · #3 (**permalink**) 02-October-2005, 10:55 PM

Quote:

Originally Posted by Manchurian Taikonaut

the recent ones & pluto can be called KBOs then ?

I should think so! lol!

naelphin · #4 (**permalink**) 03-October-2005, 02:18 AM

...Pluto as a Trans-Neptunian planet.

So a rename, TNP.

The Bad Astronomer · #5 (**permalink**) 03-October-2005, 03:16 AM

Wow. My blog entry today is about this, and I mention the IAU rumors! Now I have to rewrite it before I post it. Figures.

ZaphodBeeblebrox · #6 (**permalink**) 03-October-2005, 03:20 AM

WOW ....

WOW ....

WOW ....

So, Does This, Make Xena, a TNP, as Well?

01101001 · #7 (**permalink**) 03-October-2005, 05:07 AM

Quote:

Originally Posted by Spacemad

Here is the OFFICIAL declaration[...]

Does the 19-member division working group submitting it to the IAU make it official? Or does the WG first submit it to the Division for approval? Does the IAU have to approve the recommendation before it's really official? How does that work? Is it automatic?

Why did ArcaMax label the news as received (relatively) way back on September 26? And, no other news sources have echoed it since? Did they jump the gun on a pending announcement, or were they extrapolating, or misreporting, from the rumors last week? All other Google news items currently seem to be about the rumors, published September 21 and 22 (and a few late-comers).

Why isn't there an announcement within the IAU site, or IAU Division III? Or did I miss it?

Sorry. I'm skeptical. I'll believe it when it looks much more official.

Amphoteric · #8 (**permalink**) 03-October-2005, 06:29 AM

I don't buy it. What is being reported by ArcaMax isn't a definition and solves nothing. People were classifying the planets in groups of terrestrial, gas giants, and ..., before there was this controversy.

I'm gonna wait till the official announcement, but it seems to me if this really is the definition, then it seems like the IAU hasn't been doing anything all this time.

Spacemad · #9 (**permalink**) 03-October-2005, 07:43 AM

Quote:

Originally Posted by The Bad Astronomer

Wow. My blog entry today is about this, and I mention the IAU rumours! Now I have to rewrite it before I post it. Figures.

Sorry!!!

After I posted that I checked out the IAU website - there they have no mention of this "announcement" (except a half line entry that looks as if it's there to become a link in the moment they decide to made a public declaration), so it might well be rumour, as 01101001 implies!

01101001 · #10 (**permalink**) 03-October-2005, 08:48 AM

Quote:

Originally Posted by Spacemad

After I posted that I checked out the IAU website - there they have no mention of this "announcement" (except a half line entry that looks as if it's there to become a link in the moment they decide to made a public declaration), so it might well be rumour, as 01101001 implies!

Mind you, I wouldn't be surprised if this is the recommendation that the working group will make. It has a certain committee-sense to it, perhaps offending almost everyone a little, but outrageously offending few.

Best I can tell from sloppy browsing, if the Definition-of-Planet working group functions like the Working Group for Planetary System Nomenclature, their approved recommendation would become a provisional definition and would be voted upon (by all? by some? national members? individual members?) at an IAU General Assembly, next of which is in 2006.

I don't know what kind of problems it might encounter there. Maybe recommendations (almost) always pass. Maybe this issue is more contentious than most and might face a fight. Anyone know?

Edit: I got some more time to look around. This Early August Space.com article about UB313 discusses some possible recommendations, and concludes with:

Quote:

Yet no matter what the group comes up with, you can bank on at least one more year of debate. For a definition to be made official, it must be voted on at an IAU General Assembly meeting. The next one is in Prague in August, 2006.

So, I take it that the official-official, final-word, definition of "planet" is not upon us. It will be fun to hear what the working group recommends, though.

Kullat Nunu · #11 (**permalink**) 03-October-2005, 02:05 PM

New Scientist article about the subject from September 22nd:

Quote:

Originally Posted by New Scientist

Astronomers are arguing bitterly over how to define a planet, with some proposing that the term be abandoned completely in favour of more specific labels based on where objects are located. Two competing proposals are expected to be put forward to a formal task group on Friday, but astronomers say the debate could drag on indefinitely.

(emphasis mine)

The ArcaMax article is from September 26th. Either the working group has found an agreement, or the article is based only on rumors.

parallaxicality · #12 (**permalink**) 03-October-2005, 02:30 PM

Chokes down fury. Breathes deeply.

OK. Can I just ask that learned panel one quibbling question?

Erm... what is a planet?

It's impossible to come to any conclusion as to the nature of planets from that article. Which TNOs are to be considered planets? All of them? Is Ceres to be considered a planet? Are all asteroids? What about comets? This is a fudge, as far as I'm concerned, and resolves nothing.

pumpkinpie · #13 (**permalink**) 03-October-2005, 02:44 PM

I'm skeptical too. The article only states what Earth, Veunus, Saturn, Jupiter, and Pluto would be called. What about Mars and Mercury? We'd all assume they would be terrestrial planets too. But Neptune and and Uranus--they aren't "gas giants" so what are they called? And it also doesn't definitively mention what UB313 would be categorized as.

On Brown's page, he puts new information as links at the top of the page. The one under the release about the moon says "Rumors of a decision on the planetary status?" but isn't linked. Wonder what they will have to say about it!

I also haven't found the story on any of the reliable astronomy sites I regularly check, so I'm awaiting further announcements.....

Disinfo Agent · #14 (**permalink**) 03-October-2005, 02:52 PM

So, can we start calling asteroids "planetary objects", too? And what about comets?

Kullat Nunu · #15 (**permalink**) 03-October-2005, 03:01 PM

If they decided to call Pluto a "trans-Neptunian planet", it would be weird if that definition don't include other bodies of Pluto's size.

the_shaggy_one · #16 (**permalink**) 03-October-2005, 03:13 PM

Asteroids have long been planetary objects. Look at what the IAU calls them - Minor Planets. Comets are slightly different in that they are transient - After so many orbits, all the volatiles are blown off, and we get a boring old minor planet. A comet still qualifies as a planetary object, though.

The point of the proposed* plan is to have specific names that actually describe the different sorts of objects in the solar system. Mercury, Venus, Earth and Mars all have many properties in common, and so can be generally classified as terrestrial planets. Pluto, Quaoar, Sedna, and the three new large TNOs all have similar properties, and so can be classified as "Trans-Neptunian Planets" or "cold icy snowball planets" or any other name that specifically describes only that group of planetary bodies. I imagine that the word "planet" would eventually get dropped, and we'd be left with a system full of terrestrials, asteroids, comets, gas giants, and snowballs.

I'd like to point out that such an abandonment of outdated nomenclature is part of the natural progression of science. We're not taking away the classification, we're simply expanding it and adapting it to the facts, which makes it more sensible and scientifically useful.

* As far as I know, the working group has only proposed this solution to the department at large. I found the text of the linked article to be vauge, and possibly misleading. Since there has been no press release, or a major announcement from any of the scientific sources I've been paying attention to, I'm going to ignore this small blurb and wait for a proper announcement.

ToSeek · #17 (**permalink**) 03-October-2005, 03:58 PM

Quote:

Originally Posted by the_shaggy_one

I'd like to point out that such an abandonment of outdated nomenclature is part of the natural progression of science. We're not taking away the classification, we're simply expanding it and adapting it to the facts, which makes it more sensible and scientifically useful.

It's worth pointing out that the term "planet" has already been altered almost beyond recognition, since the original definition was, "Objects that move against the background of the fixed stars."

parallaxicality · #18 (**permalink**) 03-October-2005, 04:05 PM

Changing the definition of "planet" doesn't bother me. What bothers me is that that "definition" is no definition at all. It doesn't answer any questions, and if anything makes the scenario muddier than it was before. What's the point of calling something a "planetary object" if you're going to abandon the word "planet"? Which objects are planets, and which aren't?

Sigh. Why couldn't they have just bit the bullet and done the simple thing, saying that a planet should have a unique orbit? That would have meant only eight planets in the solar system, but it would have avoided the pointless morass the IAU seems determined to drag planetary science into for the sake of a few placemats.

HenrikOlsen · #19 (**permalink**) 03-October-2005, 04:31 PM

The thing to remember is that whatever definition they come up with will have no meaning, in the sense that the sience of the objects will change.

At most it'll influence the name, which unless you're into astrology is a meaningless label anyway, and possibly whether Michael Brown gets a few or a lot of research grants.