Is Pluto a Planet? 55
Pete Bevin writes "Apparently, astronomers are taking a vote on Pluto is a planet! It turns out that it's just another ice-ball at the edge of the solar system, and that doesn't qualify it (or the 60-plus bodies like it) for planet status. "
Silly (Score:1)
We don't even have any clear photographic evidence of WHAT Pluto is yet, and they are VOTING on it? That's stupid. Until Pluto Express is commissioned and we get some real flyby closeups of Pluto, it's all theory.
Personally, I think Pluto IS a planet. We know it is round and not irregular like a comet and it is big enough to have it's own satellite (Charon). But these debates are useless until we get a close up picture. The best we have is massively pixellated albedo pictures that only prove that Pluto is round, at best, and has lots of dark and light areas on it's surface. Voting on a 'definitive' answer at this point is stupid.
Come on .. (Score:1)
The real question here is "What is a planet?" There is no hard-and-fast, accepted definition of what constitutes a planet and what does not. Sure, you can look it up in a dictionary and get some definition for it, but as far as a scientific set of guidelines that a celestial body must meet before it can be considered a planet is concerned, there is no such definition to be found.
"Something which orbits the sun" is a fairly silly guideline; as others have pointed out, this would make asteroids, comets, and man-made space probes planets. "Something which orbits the sun and has enough mass to have been shaped into a spheroid by its own gravity" is a slightly better one. We may or may not want to include such things as a requirement for an atmosphere. (Pluto has an atmosphere right now, but as it gets further and further away from perihelion, it will freeze back onto the surface of the planet.)
In the end, an object is a planet if people think it is.
People think that Pluto is a planet, so it is, and it always will be.
Tink of the loonie, I meen poor astrologers (Score:1)
If Pluto is no longer a planet they will have to do it again. What about all the charlatans, I meen distributers who have sold astrology software, and will have to recall it.
Why do astronomers newer think about stupid, i meen alternatively gifted people feelings.
C'mon! Make this a Slashdot Poll! (Score:1)
No Subject Given (Score:1)
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mjt
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Not A Planet? (Score:1)
Not revoking planet status (Score:1)
For starters, the plan is NOT to revoke Pluto's status as a planet, but it is instead a vote on whether to confer dual status (planet/Kuiper-belt object) on Pluto.
Regarding BBC's credibility, that's up for debate, but this has been discussed in sci.astro for the last few weeks -- it's a real story.
No, having a moon (or "companion") does not guarantee planet designation, at least one asteroid has been found to have a companion, and probably many more will.
let's hear it for astronomy stories on slashdot! go rob!
Keep the Astronomy discussions coming! (Score:1)
That was a well stated group of reasons for Pluto's planetary status. Previous comments addressed Pluto's moon Charon's size. It was inferred that it was not large
enough. That is absurd. Charon is the largest natural satellite in our solar system relative to the size of its planet. Only Earth's moon is even close to this comparative size.
It is a known fact that they have been considered a double planet for some time. The object that orbits the Sun is actually the center of gravity between the two. Charon
is definitely a moon. Pluto has an atmosphere. And, it orbits our Sun on a very regular cycle that is closer to circular than any comet I have ever heard of. It is a planet
and for all that we know at this point, it could have some form of life. Luckily, they are NOT debating the possibility of it being demoted.
STOP THINKING AT ME!!!! (Score:1)
Hmm, bandersnach burgers!
Poll (Score:1)
Actually.. (Score:1)
Just mad cause your property value went to crap (Score:1)
I think it's actually rather interesting (Score:1)
If you don't want to read this sort of thing, don't read it, and for God's sake, DON'T COMMENT ON IT.
The problem... (Score:1)
(I forget the exact value, but it was picked specifically to allow Pluto, but none of the major asteroids, to qualify.)
The problems are caused by:
It's orbit, which is closer to that of a comet than a planet
It's size, which is considerably smaller than any of the other planets
It's (believed) composition, which would qualify it as a captured comet
To add to the fun, though, Pluto has what is regarded as a moon. This fits with the definition of a planet, but comets and asteroids usually don't have moons.
(You can't count any old lump of rock as a moon, otherwise Saturn has several quadrillion moons, which make up the rings, and any speck of dust that happens to fall into a stable orbit around the Earth would need to be counted.)
If the lump of rock orbiting Pluto qualifies as a moon, it MUST follow that Pluto qualifies as a planet, not an asteroid or comet. Likewise, if Pluto is relegated to either an asteroid or comet, it's moon must likewise be downgraded, and the definition of a moon altered if necessary to exclude it.
vote on if BBC is a news source. (Score:1)
But, why is it that I am more concerned that it's referanced to a BBC artical? Uh, teen age encription experts discover it's not a planet or what? BBC credibility seems more like tabloid that news level lately.... Or is it just me?
Silly (Score:1)
Seriously though, here's the list of why Pluto is considered a planet:
- Discovered in a search for a ninth planet, based on apparent perturbations in Neptune's orbit (which have since been explained otherwise)
- Discovered when we didn't really know about the Kuiper belt.
That's about all. Why Pluto isn't a planet:- Looks like a Kuiper belt object, smells like a Kuiper belt object, walks like a Kuiper belt object.....Pluto has similar composition, size, and orbital characteristics as the Kuiper belt objects (yes, similar size. It's a particularly big one, but it's not horribly out of the class)
- Orbit is highly inclined from the equatorial plane, in addition to being quite highly elliptical (the whole "closer-than-Neptune" thing)
- Pluto and Charon are quite close to being the same size; they really function more as a double-body system. I believe the barycentre (centre of their mutual orbits) of the system is above the surface of Pluto; correct me if I'm wrong.
Oh, and we have very good data about Pluto. Just because we haven't sent a probe doesn't mean we don't know anything. HST data is especially good, but you can learn a lot just from looking at little point sources. Resolving the surface doesn't really give you any more information.Like this: (Score:1)
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Not a Demotion, A Transfer (Score:1)
This has happened before. Ceres was discovered in 1801 and was called a planet for a while. It even got an element named after it, like Pluto. But eventually, when they found a bunch of other small bodies in similar orbits it became the biggest asteroid instead of the smallest planet.
I'd say Mercury is safe in it's planethood unless they find a horde of little Mercuroids orbiting near the Sun that have somehow escaped our notice until now. Unlikely.
Won't they look silly if... (Score:1)
Isn't this sort of a cut and dry issue? (Score:1)
Loren Osborn
Pluto is a Dog (Score:1)
-Eric
Science by democracy (Score:1)
Come on now, for centuries science has challenged popular beliefs in ordre to prove conventional wisdom wrong; now we're going to make science dependant on popular beliefs and who has the fastest internet connection? Blech.
The only sure thing here is that Pluto is most definately not Greek...
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Aaron Gaudio
"The fool finds ignorance all around him.
swap(Neptune, Pluto) (Score:1)
"My very energetic mother just sent us practically nothing" ?
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Aaron Gaudio
"The fool finds ignorance all around him.
Planetary discrimintation? (Score:1)
Maybe its just a case of the big planets trying to close out the game, now that they've won.
:( (Score:1)
It is (Score:1)
A couple of years ago I worked on a project when JPL had a call for proposals for sending a probe out there. Really interesting stuff and a lot of design challenges.
One of the mission drivers was to get the probe out there before 2018 or so. At that point Pluto is going to swing out far enough that it's atmosphere of ammonia (or some other nasty gas) is going to collapse back into a solid. Right now we're relatively lucky in that Pluto is at it's closest point in it's orbit - a measly 30 AU's or so. Basically at the end of the report we wrote up we said that a probe has to launch by 2005 or it gets REALLY hard to get it out there in time.
Anyway, two facts compell me to think it has to be a planet (note: either of these by themselves is not enough since they occur in other places in the solar system) 1) it has an atmosphere, 2) it has a moon (or are there two now?) None of the other objects out there or in the Kuiper Belt are known to exhibit those qualities.
There must be nothing better to do..... (Score:1)
So Jupiter is a giant ball of gas as well. I vote we eliminate THAT as a planet, too!!!
Fungi from Yoggoth will wreak havoc (Score:1)
:-)
Tink of the loonie, I meen poor astrologers (Score:1)
Ooops..... you Mean Uranus, Neptune and Pluto
Mercury is one of the classical 5 planets (other than earth)
But what about... (Score:1)
Oh, and if anybody happens to have a decent copy of the fourth episode of _The Tenth^h^h^h^h^h Ninth Planet_, I'd be glad to come over and help you relabel it
Earth is just a waterball! (Score:1)
70% of Earth's mass is water, so it is mostly not either a gas giant or Mars-style solid rock planet.
Gas Giants do not count random rocks as planets anyway.
To define a planet (Score:1)
In this definition moons will not work out unless they have sub-moons. The sun will not be a planet unless you compare it to the rest of the galaxy (perhaps add a kludge stating "can have no continuous thermonuclear reactions over a large volume"). So a planet is a relative definition here.
Mercury, Venus, Earth, and Mars have a definite period of geological history so they are all planets.
At first it would appear that Jupiter is not a planet because it doesn't have exterior rocks, but ask any geophysicist if solids are all that there are to geology. The answer then is that Jupiter, Uranus, and Neptune are then planets.
It is now clear than Pluto is not a planet because it does not have any definite geological history. Sure it has geology but it has no history past the point in which it coalesced into a dirty snowball. It does satisfy the other half of my definition but a history must be found for the first part.
They're just picking on Pluto... (Score:1)
One astronomer made the good point that although Pluto is erratic, it still meets the planetary criteria. "Just because a duck is small, you don't call it a chicken". The astronomer against Pluto didn't even bother to give any coherent argument, just kept saying that Pluto was a "weeny little thing" and that it was nowhere near being one of the "proper planets". I mean, what kind of garbage is this?
And since when has a poll been the correct method for determining scientific "truth"? We don't have people voting on whether we should keep Einstein's theories, or whether gravity exists. I think the whole concept behind this is ridiculous. I agree that Pluto has some irregularities, but it doesn't seem to meet the criteria for other astronomical objects - and there's no just cause to throw out the entire scientific process.
Anyway, my $.02.
Leilah
Actually, "Earth's" "Moon" is a planet (Score:1)
If you work out the math, you'll see that the force of the sun on the "moon" is always "winning" against the force of Earth on the "moon"--the orbit of the "moon" is always bent toward the sun (unlike, say, the moons of Jupiter, whose orbits are always concave toward Jupiter). So what we think of as Earth's moon is more logically considered a companion planet to the earth. It's quite a bit smaller, and its orbit is significantly perturbed by Earth, but you really can't make a case for saying it orbits Earth.
At least, that's what I remember learning in some class somewhere.
mikey
clinton is president; pluto is a planet; bbc is .. (Score:1)
Silly (Score:1)
I'm quite curious .... (Score:1)
would you specify exactly what the "more pressing problems" are that the International Astronomical Union should be addressing?
Immigrant rights for Martians? Mining regulations for Ganymede? Food for hungry Titanites?
The IAU are the people who regulate the definition of planet
IAU official's statement! (Score:1)
Thank you very much for "immortalizing" me in your humorous but thoughtful song "Planet X". I am very flattered! I was aware of your poem but did not know that you had made a song of it and recorded it in your album "Shining My Flashlight on the Moon".
Yes, your song reflects my opinion with regard to the planet Pluto. I still think that it would be a grave mistake to degrade Pluto to a minor planet. Although Pluto is small compared with the other major planets, it is still more than twice as big as the largest known minor planet, Ceres. Furthermore, it is not only Pluto's size that counts, but the entire fascinating story associated with that planet which has been known as such for 67years. Now that Pluto's discoverer, Clyde Tombaugh, is dead, Pluto's status has become even more a closed chapter in the annals of astronomy. WGPSN has started to think about how to commemorate him, preferably by naming some large feature on Pluto or on its moon, Charon, after him.
Kaare Aksnes
President -- IAU Working Group for Planetary System Nomenclature
Mnemonics (Score:1)
Meaningless. (Score:1)
Tink of the loonie, I meen poor astrologers (Score:1)
IMHO, its if doesn't classify as a planet then the damn thing is just a wannabe. Just like NT.
The fact that it will annoying the astrologers are just a big old bonus if ya ask me.
Lets ditch pluto! =)