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http://www.usatoday.com/tech/science...troversy_x.htm
Was there always one between Mars and Jupiter, Cers? And Pluto's sister planet, Charon? And a planet is now: all round objects that orbit the Sun and do not orbit another planet. That not count asteroids? etc I also like the way they use what they're defining in the definition of a planet, ie, a planet
Planets have an atmosphere. :rolleyes: I realise that when most of the planets in our solar system were discovered that there was no way to know if they had atmospheres or not - that's not the point. "Scientists should show that they can admit mistakes and rectify them." I can also understand why scientists want to make categorizing easier for future discoveries but we can make those decisions when it happens. There is no reason to confuse ourselves further by making baseless nondefinitions.
UB313? If it is really a planet in our solar system it should have the name of a god. In the interest of being neat, astronomers catalogue everything, but this doesn't mean we have to get lazy with common names.
>That not count asteroids?
Ceres is an asteroid. It is not currently considered a planet, but would be under the new definition.
> Planets have an atmosphere.
Once known as a lowly moon, Luna will enjoy its new status as a planet.
Similar names are good enough for the stargate programQuote:
Originally Posted by citizen
Pluto doesn't have an atmosphere. When it's close enough to the sun some of the ices melt, but it quickly escapes away. Mercury also has nearly no atmosphere.Quote:
Originally Posted by citizen
There are, however, some moons in the solar system that have a tenuous atmosphere.
> Pluto doesn't have an atmosphere.
And currently Pluto is not a planet. At least it's better than "anything round and within the Sun's orbit." I meant to add to that statement, not rewrite it. Sorry.
>And currently Pluto is not a planet.
Which planet are you living on? hahaha
Currently Pluto's status is being debated within astronomical circles, but is still generally accepted as a planet.
Going back to the original post, it still under debate. Clearly it will not be approved. It's just too generalistic and a bit silly, IMO.
It would be preferable to create a new official name for round objects that orbit the sun on which planets and asteroid-like objects could be fit. But arguably this is all the fault of astronomers who didn't really ever came to an agreement as to a concrete definition of what a planet is. This is not the first time some astronomers have came with ludicrous options.
Probably this (hopefully) false start will stir that debate and soon we will have once and for all a complete definition. Some astronomers defend that the solution is to look back at how the various objects were formed and if they are evolving objects. This also brings the need to create a definition for proto objects and dead objects that is distinguished from that of a planet which resides in the middle of these two.
Well when I was in grade school I learned about nine planets and that was fine with me. They were at least a few thousand km in diameter, had atmospheres, and sped around the Sun. That's a very comprehensive logical definition. Mercury and Pluto can also not be a planet if the whole argument is going to revolve around that, but no one seems to be able to tell me if either Pluto or Mercury definitely do not have atmospheres.
I also want to make it clear that I am not an astronomer, so arguing with me is a big waste of your time. *sighs*
It has been since its discovery.Quote:
Originally Posted by citizen
http://www.exeter.ac.uk/Mirrors/nineplanets/
It may not be considered a planet when all this debating is said and done, but it is currently a planet.
I wouldn't say generally. In fact a very representative number of scientists argues against Pluto definition as a planet for many years. Many are the reasons. It's size and mass being smaller than even the moon, the fact that it has asteroids in the Kuiper Belt bigger than it is (and equally round), the fact that it behaves exactly like a comet (it even has a layer of ice that is being slowly evaporated into space), and the fact that even its discovery was based under false premises and a lot of romanticism.Quote:
Originally Posted by Decrypt
Some astronomers go to the point of refusing to adop Pluto as a planet on their debates and conversations.
The two stupid rocks at the opposite ends are going to be the bane of me as I write. Currently I am torn between explaining again (when I've defended myself well) or letting others voice there opinion. Or just pick on me and my innocent, logical, unambiguous definitions of planethood.
I'm resting for now. I've run out of tea. If necessary I will come back with a minimal circumference for planets, but then a comet will come along which is smaller, has an atmosphere. and didn't escape the Sun's gravitational pull. :D Meanwhile I am waiting for a more square-shaped planet to appear, to prove my real belief: man knows nothing, he just gets better at guessing every time.
This is so true, it's painful. Until more knowledge is attained the whole debate does look like a clear sign we simply don't know enough yet. Defiitions do evolve with time.Quote:
Originally Posted by citizen
Pluto does have an atmosphere. But then and again, so do some asteroids :)
>> UB313? If it is really a planet in our solar system it should have the name of a god.
They're naming it some time this week.
>> It would be preferable to create a new official name for round objects that orbit the sun on which planets and asteroid-like objects could be fit.
Well, if you read the link, :p, they're called plutonians or something.
>> It has been since its discovery.
They're questioning whether it really is a planet though at the moment. Isn't it mostly ice or something? It's generally defined as a planet (Pluto), amongst the non-scientists. Personally, I don't know enough to say whether or not I think it is a planet, but if that new definition holds, it's a planet!
Isn't this a better definition - any celestial body (other than comets or satellites) that revolves around a star. Or - Planet is a literary magazine based in Wales. Sometimes, bless it, google doesn't really know what we want.
Doesn't anything with any kind of gravity have an atmosphere? It's logical, so even asteroids and shooting stars must have an 'atmosphere' of some description. Just because it's not a large one, doesn't mean there's not one there. After all, an atmosphere is a 'the envelope of gases surrounding any celestial body', which can be anything!
> Well, if you read the link, , they're called plutonians or something.
Plutons. But that's a different thing. It's to name only objects that are near-like planets. It's part of this whole silly proposal.
> Doesn't anything with any kind of gravity have an atmosphere?
It depends on several factors. Definitely mass is the major one. But temperature plays a big role. Too much cold and the atmosphere freezes to the ground. Too much heat and it evaporates into space. "Too much" here being obviously a relative term depending on the type of atmosphere. Other factors that can take atmosphere away from a body are distance to the star and the type of star (a red giant will definitely consume the atmosphere of many of its planets).
So every asteroid whizzing around the sun is a planet? ;) If not, please distinguish between a planet and an asteroid.Quote:
Originally Posted by twomers
A planet need to be diverse. Most plutons are just balls of rock
>> Most plutons are just balls of rock
And ice I think. But aren't planets, ie Earth, mostly balls of rock too (albeit molten rock)
I have two planets that.... ahhh forget it
To get technical about it, I think that the criteria should be volume (note - not
mass, due to the fact that other stellar phenomenon may prove quite dense),
"atmosphere", and primarily, eccentricity of orbit - perhaps a range of values in
which the orbit must be to be considered. Depending on the definition of
atmosphere, a nice, well defined standard could be established which acounts
for non planetary objects. Assuming that a large object with suitable volume
and orbit but no atmosphere occurs, that could be considered a planetoid.
The volume spec would rule out most asteroids, and the eccentricity
would rule out comets.
Those criteria could help standardise the naming of other bodies such as comets
and asteroids, but at the end of the day, does having a standard name for
objects that fall into specific categories really matter? When scientists talk about
a comet, it'll be refered to by the name of the discoverer or some code, same for
all objects really. When studying such objects, the type is less important than
the values of the properties mentioned.
Lastly, I think Charon is a proposed moon of Pluto? There's some ambiguity on
that matter too I think.
And then you would be removing from the definition of planet an object that, being a planet, would for instance have an eccentric orbit around the sun.
No, the definition of an object must not be based solely on it's physical properties.
Just like with the animal kingdom in which we so cleverly divided everything into ever so tighter compartments until we arrived onto the species, objects in space must probably be categorized a similar way. There won't be just one type of planet, but different "species" of planets. The same with asteroids and comets. In fact, this is what has been done with stars already.
This is probably a saner and safer way to do it. There is also a big difference between how a planet (as we know it today) was formed and a comet or asteroid. This signature, just like with the animal kingdom, should be in the basis of what belongs or not to the planet "family".
There is also the property of the planet being "alive" or not. Is there geological activity? Is there climate? Is there seasons? Is the planet evolving? Is there life? These and some other questions, individually analized or put together into groups may also help establish what is a planet, what is not, and what type of planet it is.
Aaah the human urge to categorize everything.
A rock stays a rock, I can call it a balloon, it will remain the same object with the same characteristics.
It's easy to have conventions/rules etc etc... Just like its easy to pick describing names for variables in code.
But when conventions are being rearranged that there can be discussions about then the use of these conventions get lost.
I agree partially. But I think that reasoning comes from those situation where naming conventions don't fit the objects being categorized.
The debate among the definition of a planet is old. Very old. Arguably the reason why a consensus has never been reached is because we don't know enough yet. We only know the planets of our solar system. We can theorize of how other planets may look like that are different from those in the solar system because we already kow something on how they are created and evolve until they either die "from natural causes" or are destroyed. But we certainly don't know enough yet to determine with a certain degree of precision what a planet is.
We cannot deny the need to have a clearly categorized "fauna" of solar and extra-solar objects. The advantages go well beyond astronomy. The passing of knowledge, a better understanding of what surrounds us and simply the need to properly comunicate about these matters are some of the consequences of having things categorized. It is tue though that we make mistakes.
In fact, it's never easy to name things. And the secular debate of what a planet is clearly shows this. As our undertanding grows, so does our perception of prior conventions. For the greeks a planet was simply a moving shiny object against the celestial sphere. Stars stayed put. Planets didn't. We cannot pretend we are above this need to categorize things. It is the only way, we humans know, of understanding them.
Well, it's official. As of today, Pluto's no longer a planet.
My 6 year old nephew's gonna hate the scientests!!!!! He has a song to remember them and all!
They should have grandfathered Pluto as a planet. Pluto is everyone's favourite planet/dog.
Quote from the article:
>Pluto was disqualified because its oblong orbit overlaps Neptune's.
THAT'S why it was disqualified?!?!? Psh...we've known that for ages!
I think a group of computer scientists should get together and decide if Pluto is a planet or not.
It's quiet incomplete that article from Reuters. There were several other factors. But mainly the reason was that the definition of the word "planet" was redefined. The orbit was a major and important change.
In oder to be considered a planet, the object must (along other restrictions) have cleared all other objects around its orbit path (and not be a satellite).
This does indeed offer a more clear picture of what a planet is. I'm not sure what they are going to do with proto-planets and planets that have the needed mass to clear foreign objects around their path but haven't yet (didn't collide, captured or expelled those objects yet).
But all in all, I believe this was a good thing. Especially on this age where the search for extra-solar planets is starting and thus a clear understanding of what is a planet becomes a clear necessity.
I never had to take natural science for my major.Quote:
Originally Posted by DavidP
What are we doing to do without an underworld component in the solar system? We've lost our yang. The balance between the gods is all skewed now. We're doomed.
well knowledge develops and so do definitions. its good when definitions take precedence over traditions.
imagine ppl in school being taught: "well thats the "definition" of a planet, but there are some exceptions due to tradition..." i always hated exceptions. (exception handling not included ;) )
Watch out! Pluto ( the god of death) will get his revenge . . . ;)
from what i know charon the other one and pluto arent planets (yes pluto is no longer a planet watch the news) there considered "dwarf" planets ,if they let pluto be a planet than most liekly thered be another 9 or 10 other things thatd have to be planets and charon didnt they discover that 2 years ago?it was on the news and its status of being a planet had been on and off for a while
Charon was discovered in the 80's, I think. Pluto has two other moons. Those are the ones discovered last year. Charon has been considered a moon of Pluto, although it was known from the beginning they rotated around each other, instead of around Pluto as with other moons. It was another controversial decision to add to the many surrounding Pluto since the day of its discovery.