Is Pluto a planet?

The Radiator

Apaarently its naht but i tink its a planet cos my science taecher sed it wos! ??? :P

Plug

Its a dwarf planet.

The Radiator

Plug wrote: »

Its a dwarf planet.

But technically it doesn't orbit the sun on the same course? SO IS IT A PLANET AT ALL??????1111111111!111!!!!1

shedweller

http://en.wikipedia.org/wiki/Pluto#Classification

The debate came to a head in 2006 with an IAU resolution that created an official definition for the term "planet". According to this resolution, there are three main conditions for an object to be considered a 'planet':

The object must be in orbit around the Sun.
The object must be massive enough to be a sphere by its own gravitational force. More specifically, its own gravity should pull it into a shape of hydrostatic equilibrium.
It must have cleared the neighbourhood around its orbit.[133][134]
Pluto fails to meet the third condition, since its mass is only 0.07 times that of the mass of the other objects in its orbit (Earth's mass, by contrast, is 1.7 million times the remaining mass in its own orbit).[132][135] The IAU further resolved that Pluto be classified in the simultaneously created dwarf planet category, and that it act as the prototype for the plutoid category of trans-Neptunian objects, in which it would be separately, but concurrently, classified.[

I was a bit disappointed at it's demise as a planet but it doesn't change much. The probe "new horizons" is on its way to it as we speak. Funnily enough, Pluto was a planet when New Horizons launched but lost it's planetary status afterwards!

Dude111

It IS a planet but for some reason they say it isnt

Cú Giobach

What intrigues me is how can a "dwarf planet" not be a planet.

## It must have cleared the neighbourhood around its orbit.

Is Jupiter no longer a planet? Jupiter Trojan

Planet Pluto Abú.

djhaxman

If Pluto is a planet then we would have to call Eris, Makemake, Haumea and Ceres planets too, as well as all the yet undiscovered bodies as large as those. The list would be endless.

All of those bodies do not meet the conditions on the list.

OP, I'd worry more about my grammar than whether Pluto is a planet or not, if I was you.

Cú Giobach

djhaxman wrote: »

If Pluto is a planet then we would have to call Eris, Makemake, Haumea and Ceres planets too, as well as all the yet undiscovered bodies as large as those. The list would be endless.

So?

Zubeneschamali

djhaxman wrote: »

If Pluto is a planet then we would have to call Eris, Makemake, Haumea and Ceres planets too

Ceres was a planet for about 50 years after its discovery, then it was an asteroid until 2006, now it's a dwarf planet.

djhaxman

Zubeneschamali wrote: »

Ceres was a planet for about 50 years after its discovery, then it was an asteroid until 2006, now it's a dwarf planet.

Exactly my point.

Rubecula

Dwarf planet = a celestial body that is just big enough to be spherical. I think that Mercury is the smallest true planet. i.e. a body that has it's own orbit around the sun.

Hope that helps.

BULLER

If pluto was a planet then our solar system would have possibly hundreds of planets.

Simple as that folks. It's a dwarf planet, not big enough to be a planet.

Zubeneschamali

BULLER wrote: »

If pluto was a planet then our solar system would have possibly hundreds of planets.

Which would obviously be intolerable!

osnola ibax

Isnt it out in the Kuyper Belt and have a moon almost equal in size to it so that it could actually be termed a binary system unlike any of the other know planets.

Turtwig

OP please use proper spelling and grammar. It's least amount of courtesy you can show when asking people to devote their time to answering a question for you.
So instead of summarising I'm just going to post the video clip with the appropriate time start.

osnola ibax

Malty_T wrote: »

OP please use proper spelling and grammar. It's least amount of courtesy you can show when asking people to devote their time to answering a question for you.
So instead of summarising I'm just going to post the video clip with the appropriate time start.

wow, great video, that guys got buckets of charisma,he is like the Mohammad Ali of Science

Overature

One of the reasons that Pluto isn't a planet is that it is not big enough to exert a large enough gravitational pull to clear its surrounding region of debris, one of the criteria that a celestial body must fill before it can be called a planet

Damokc

Stephen Fry said its not so..end of thread

The Radiator

Thanks for the replies everyone

Damokc wrote: »

Stephen Fry said its not so..end of thread

Stephen Fry is far too pro-British for me to take anything he says seriously

shanered

When does a hill become a mountain and a stream become a river?

Turtwig

shanered wrote: »

When does a hill become a mountain and a stream become a river?

Surely that's more appropriate to ask in the Geography forum? As far is science is concerned definitions aren't based on the popularity of their use among local people. So I'd very much hope that the definition of Mountains is such that it is chosen in a way to further the understanding of the plate tectonics and the like.
(Iirc, it has to do with the steepness and elevation.)

In the case of astronomical definitions, it's basically taxonomy based on the most useful and pragmatic definitions available to us. Radians instead of degrees for trigonometry if you prefer.

Cork boy 55

I really think they should send Pluto a certificate or something and make it an honorary planet...after all..it's been generally accepted as one for a long time.
...akin to an honorary degree !

gbee

The Radiator wrote: »

Apaarently its naht but i tink its a planet cos my science taecher sed it wos! ??? :P

It was a planet in my youth too, and it's a planet in my eyes still ... and yes I know the earth is roundish ~

John mac

It was, but its not now.!
because the boffins voted on it.:D

jensennhook

Zubeneschamali wrote: »

Ceres was a planet for about 50 years after its discovery, then it was an asteroid until 2006, now it's a dwarf planet.

I thought Ceres is a moon i'm not sure if what planet, that's what i read from a book:p

FreudianSlippers

Is it a dwarf planet or a planetesimal? Either way, it's not a planet - if it were then we'd have to make larger planetesimals in the Kuiper belt planets.

Rubecula

jensennhook wrote: »

I thought Ceres is a moon i'm not sure if what planet, that's what i read from a book:p

No it is not a moon in that it does not orbit a planet. It is most certainly in the asteroid belt.:)

oneillMan999

Yes its a planet, just cause a few astronomers decided they didnt want it to be a planet dosent mean its not, Pluto is a planet in the solar system and always will be.

Zubeneschamali

oneillMan999 wrote: »

Pluto is a planet in the solar system and always will be.

Ceres, Pallas, Vesta and Juno are planets in the solar system, and always will be.

Or perhaps they never were?

Or perhaps it's just a matter of definitions.

tallaghtmick

I hate the fact they downgraded it to a "dwarf planet"

Surely a group of dwarves should argue this as it makes them out to be "dwarf humans" and not human..........:pac:

iPlop

The Radiator wrote: »

Apaarently its naht but i tink its a planet cos my science taecher sed it wos! ??? :P

This is language they speak on pluto???

Stacey.

Yeah I think it's a planet.

Turtwig

Sink The Banana wrote: »

This is language they speak on pluto???

It's remarkably comprehensible.

FreudianSlippers

FreudianSlippers wrote: »

Is it a dwarf planet or a planetesimal? Either way, it's not a planet - if it were then we'd have to make larger planetesimals in the Kuiper belt planets.

Answered my own question

The term "planetesimal" refers to small bodies that orbited the Sun prior to the planets' formation. In 2006, the International Astronomical Union (IAU) ruled that a "dwarf planet" is a nearly spherical celestial body orbiting the Sun that has not cleared its orbital path of debris, as have the traditional planets.

In any event, Pluto is most certainly not a planet.

calabi yau

oneillMan999 wrote: »

Yes its a planet, just cause a few astronomers decided they didnt want it to be a planet dosent mean its not, Pluto is a planet in the solar system and always will be.

No, this is not the case. It does not behave like the other planets. Please watch DeGrasse Tyson, the man partly responsible for downgrading it, on the subject. He has convinced me. Just because you have an affinity towards it, does not "make it so"

slade_x

oneillMan999 wrote: »

Yes its a planet, just cause a few astronomers decided they didnt want it to be a planet dosent mean its not, Pluto is a planet in the solar system and always will be.

Its not about not wanting it to be a planet its about appropriate categorisation. Pluto hasnt left the solar system as a result, it is still very much a member, now it belongs in a more appropriate category of objects which will grow exponentially in the next few years as more and more objects like it will be isolated/ found

And i wouldnt consider The International Astronomical Union with over 10,000 members just a few astronomers. Classification of such objects and standards are not for the general public to decide. IAU is not a bunch of amateur astronomers it is an organisation of Professionals. Membership requires a Ph.d at the very least.

Rubecula

Pluto is quite reflective. i.e it is white. It is also small. i.e. a dwarf.

I hereby declare that from now on Pluto is really a White Dwarf.:D:D:D

Seriously, just because we we taught in school that Pluto was a planet does not make it so. I was also taught that there is a planet X that is out there and astronomers were looking for it. It is not there as far as we know, and wishing it was does not make it so.

As much as we may dislike the idea, it is something we just have to live with. Pluto is still there and still the same as it was, so who cares what it is called really, it won't affect Pluto, which does not care one iota what we call it.

Turtwig

Edwin Schrodinger wrote:

Unfortunately, school teaching keeps up certain traditional views, which have been out of date for many years and which obscure the understanding of the actual state of affairs.

Love Edwin.:D

osnola ibax

Rubecula wrote: »

Pluto is quite reflective. i.e it is white. It is also small. i.e. a dwarf.

I hereby declare that from now on Pluto is really a White Dwarf.:D:D:D

Seriously, just because we we taught in school that Pluto was a planet does not make it so. I was also taught that there is a planet X that is out there and astronomers were looking for it. It is not there as far as we know, and wishing it was does not make it so.

As much as we may dislike the idea, it is something we just have to live with. Pluto is still there and still the same as it was, so who cares what it is called really, it won't affect Pluto, which does not care one iota what we call it.

I remember hearing about a tenth planet "Smily" from my physics teacher.

clintondaly

so this isnt a thread on loved Disney characters

Batsy

Up until 2006, there were deemed to be nine planets in the Solar System.

Now there are only eight.

In the late 20th and early 21st century, many objects similar to Pluto were discovered in the outer Solar System, notably the scattered disc object Eris in 2005, which is 27% more massive than Pluto. On August 24, 2006, the International Astronomical Union (IAU) defined what it means to be a "planet" within the Solar System. This definition excluded Pluto as a planet and added it as a member of the new category "dwarf planet" along with Eris and Ceres. After the reclassification, Pluto was added to the list of minor planets and given the number 134340.

Pluto has four known moons, two of them being discovered as recently as 2005 (Nix and Hydra) and one (provisionally named S/2011 P 1) discovered on 20th July 2011.

http://en.wikipedia.org/wiki/Pluto

Zubeneschamali

Batsy wrote: »

Up until 2006, there were deemed to be nine planets in the Solar System. Now there are only eight.

This is the short version, which rather encourages the "Pluto is so a planet!" brigade.

In fact, there used to be 5 planets: Mercury, Venus, Mars, Jupiter and Saturn. Then Copernicus, Kepler and friends decided Earth was a planet, too. Then Uranus was discovered, so there were 7. Then Ceres, Pallas, Juno and Vesta were discovered, and there were 11 planets for more than 30 years. Then Neptune and a load more asteroids were discovered, so one planet was added and 4 demoted and we had 8. Then Pluto was discovered, and we had 9. Finally pluto was demoted for the same reason the Asteroids were, the discovery of a whole class of similar small objects.

In the longer version, it's clear that Pluto wasn't suddenly picked from the "real" list of 9 and demoted, this kind of reclassification has been going on since the 16th century.

Cú Giobach

Terrestrial Planet = Planet
Gas Giant Planet = Planet
Ice Giant Planet = Planet
Dwarf Planet ≠ Planet

RichieC

Zubeneschamali wrote: »

In the longer version, it's clear that Pluto wasn't suddenly picked from the "real" list of 9 and demoted, this kind of reclassification has been going on since the 16th century.

Yea but this is different since it's the only planet discovered by America. which is the only reason this got the air time it did.

oneillMan999

slade_x wrote: »

Its not about not wanting it to be a planet its about appropriate categorisation. Pluto hasnt left the solar system as a result, it is still very much a member, now it belongs in a more appropriate category of objects which will grow exponentially in the next few years as more and more objects like it will be isolated/ found

And i wouldnt consider The International Astronomical Union with over 10,000 members just a few astronomers. Classification of such objects and standards are not for the general public to decide. IAU is not a bunch of amateur astronomers it is an organisation of Professionals. Membership requires a Ph.d at the very least.

Interesting...








Its still a planet though..

Agent Smith

Turtwig

Why address NASA? ? ?

RichieC

Because space belongs to america!

shizz

looks more like Venus as well

Turtwig

shizz wrote: »

looks more like Venus as well

Ehh? ? ?



Edit : I'll have me humble pie, just realised what you meant.

Cú Giobach

shizz wrote: »

looks more like Venus as well

I think it looks more like a Mars/Io cross, and a "halfbreed" of a moon and a planet campaigning for the reinstatement of Pluto seems quite logical*.



*Could be an illogical use of the word logic.