Should Pluto be a Planet or be a Dwarf Planet

[DommyDevil18]

When we were kids we remembered the nine Planets but now we remember the 8 Planets and 5 dwarf planets one of which being Pluto. Now who thinks that Pluto should be a Dwarf Planet or be a Planet again but hold on to your thoughts because I got something to say.

In 1801 an Italian Astronomer Giuseppe Piazzi discovered the then 5th Planet Ceres in between Mars and Jupiter it is a small world but it was exciting. A couple of years passed and they find a new one Pallas. Then another year passed and they found Juno and another year passed and they found Vesta. But more and more of these "Planets" were being found and it was getting incredibly uncomfortable for them to be Planets but a new label Asteroid was born and they were all including Ceres reclassified Asteroids. Of course in 2006 a new definition of what makes a Planet was made and Ceres was reclassified as Dwarf Planet.

Now Pluto discovered in 1930 by Clyde Tombaugh and was then the 9th Planet. Initially thought to be the size of Neptune but in 1978 Plutos moon Charon was discovered and they found that Pluto was much smaller. In the next few years they found more objects in the same area as Pluto (sounds familiar to Ceres doesn't it). These were Sedna Eris Haumea and Makemake. Pluto in 2006 not much before Ceres was reclassified Dwarf Planet.

A Planet is an object that 

1) Orbits the star

2) Has sufficient Gravity to have a round shape (This is called Hydrostatic Equilibrium)

3) Cleared the Neighbourhood

Pluto is in a region called the Kuiper Belt and thus has not cleared the neighbourhood. 

[Alien 13]

Pluto will allways be a planet in my mind any object that can hold a moon in orbit has to be a planet.

Alan

[jake_wright]

Exactly as above in my opinion

[Cath]

I still think of Pluto as a planet too, which is fine by me.

It's all just sematics anyway. What we choose to call them doesn't change them in any way what so ever, they are what they are.

If we had a binary planet in our system, say the Moon was the same size and mass of the Earth, what would we call Earth and it's binary twin the Moon?

[AstroJon]

Pluto

1930-2006

Revolve in Peace

[trazor]

You can not rewrite history, Pluto is a planet, end of.

[RikM]

Plenty of large asteroids have little moonlets orbiting them, nothing special about that. There are loads of largeish roundish icey chunks floating about out there and are either all planets or all not planets. Do we not correct things when new observations show that our initial thoughts were wrong? By the current system of classification, Pluto isn't a full planet. 

[AlexB67]

It makes sense IMHO for it to be excluded, though I may not gain any popularity for saying so,  but there is no point attaching sentimental historical values to something for the sake of what is in the best interest for science. If the reclassification had not been made, there would be a bigger grey area of other bodies that could arguably also qualify as a planet.

[astro mick]

I think a little sentiment is great.For me Pluto is still a Planet.

I grew up with that,and an exception could be made.

[Ags]

Why is Greenland not a continent? When is a hill a mountain? These are all arbitrary decisions that have nothing to do with science. It's cultural, and should be left in the hands of UNESCO.

[rowan46]

You can not rewrite history, Pluto is a planet, end of.

People do rewrite history all the time and often for the very good reason  that new information means the old history was wrong. Science does the same thing

[AlexB67]

Why is Greenland not a continent? When is a hill a mountain? These are all arbitrary decisions that have nothing to do with science. It's cultural, and should be left in the hands of UNESCO.

Perhaps I am missing the point, but it is relevant IMHO. If you are going to invent a classification system it would make sense to keep it sensible an minimise counts. Imagine if you have a number of different objects and a number of different baskets to put them into, the objects could be pebbles of different sizes, it would make sense to do it to minimize the number of baskets  and amounts in each basket in the best/sensible way possible. There would be no point in saying a hill is anything over 10 meters, and a mountain anything over 10 miles, most would not fit in that classification on earth anyway, so there is some sense and science to it and there should be.

Sorry, Tell me to go away at any time for being pesky  .  Not looking for an    , just curious why you'd say that.

[Kirscovitch]

I read somewhere that Russia has more surface area than Pluto. IMHO that's kind of small to be a planet. Sorry Pluto.

[Ags]

Perhaps I am missing the point, but it is relevant IMHO. If you are going to invent a classification system it would make sense to keep it sensible an minimise counts. Imagine if you have a number of different objects and a number of different baskets to put them into, the objects could be pebbles of different sizes, it would make sense to do it to minimize the number of baskets  and amounts in each basket in the best/sensible way possible. There would be no point in saying a hill is anything over 10 meters, and a mountain anything over 10 miles, most would not fit in that classification on earth anyway, so there is some sense and science to it and there should be.

Sorry, Tell me to go away at any time for being pesky  .  Not looking for an    , just curious why you'd say that.

To me it is just a collision of language and science. 'Planet' has a lot of connotations but ultimately they are just the 'continents' of our solar system. For historical and cultural reasons we have determined that they are important i.e. planets. I don't agree with the Dwarf Planet thing, it's trying to dress up a cultural thing in meretricious science. The real problem answered by Dwarf Planets is you can't expect schoolkids to memorize more than a dozen or so planet names :-)

[lukebl]

Everything, from the smallest meteorite to Jupiter, is just a bit of rock/ice of varying sizes orbiting the sun. It just happens that the biggest ones have been called planets since before the invention of the telescope. It's just an archaic naming system. It seems to me that the name 'planet' is irrelevant now that we know that the solar system has incalculable 'bits of stuff' of varying sizes orbiting the sun, and scientists are desperate to find a way of labelling them and ensuring that the big ones (particularly, I suspect, Earth) are somehow different and special. It all seems a bit arbitrary.

Jupiter is so phenomenally different from Earth and Mars, yet both are deemed planets, but Pluto, Ceres, Eris and all the others aren't. Either they're all planets, or none of them are. However, people do like to categorise and list things. I guess it's in our nature. And it keeps scientists in employment.

Anyway, I'm an old git and Pluto is a planet. End of.

And don't get me on the subject of Exobiologists! They are people who get paid as specialists on life beyond Earth, yet we've never discovered ANY evidence of extraterrestrial life so how do we know? It must be amazing at dinner parties to be introduced as an expert in something which has never been discovered or proven!

Sorry, I ramble...

[astro mick]

What about the tiny moons of Saturn,they orbit their parent star,which orbits the sun,and some have swept their orbits clean within the ring system.

Ok I,m being picky.

[bish]

Might as well leave Pluto as a planet. There's not really any need for a defined class of bodies called planets as far as I am concerned. Some bodies are round (ish), some are mainly gas, some are rocky. All solar system objects with different properties.

[sbooder]

Pluto is an annoying dog belonging to an annoying mouse, who in turn is married to another annoying mouse.  But seriously...he is annoying!   Oh come on! someone had to say it?

[jnb]

Pluto is not a planet. If you count pluto as a planet then you have to include Ceres, Makemake and a load of other bodies that are not distinct in the way that the planets are which just diminishes the term.

[Tykeviewer]

I was taught the 9 planet system at school, but consider that I was short-changed because I was never told of the existence of Ceres, MakeMake, Haumea etc.  At least with Pluto being reclassified, it prompts people to wonder why, which in turn leads to them discovering these other dwarf planets.

[russ]

What i want to know is did they consult the Plutonians before deciding to downgrade their planet. This could have easily started an inter-planetary war on a scale never seen before.

I never understood the reasoning behind downgrading it. Generations had been taught the solar system had 9 planets and it should have stayed that way. It was classified a planet from the start, should have remained that way.

[ollypenrice]

You can not rewrite history, Pluto is a planet, end of.

Both science and history are constantly being rewritten. That's why they both improve...

In this case nothing new was discovered about Pluto, what was discovered was that there were going to have to be an awful lot of planets if we kept the title for Pluto. We chose to change the meaning of a word, and this is something that we do all the time. Indeed we do it it without realizing it. ('Silly' used to me 'crafty or cunning.' Quite a change! 'Tell' used to mean 'count' etc etc etc.) 

Had Lowell's observatory found Pluto by accident, rather than because they were looking for a planet, would they have called what they found a planet? Had they known how small it was and that it was having no significant effect on the orbit of Neptune, would they have called it a planet? I don't thnk they would.

Old Percy Lowell himself found canals on Mars at the same observatory.     Fortunately we can rewrite history!!!

 lly

[Knight of Clear Skies]

It's just semantics really. By one sensible definition of planet there are eight in the solar system, by another (gravitational self-rounding) there are many more - but we couldn't tell you how many. But it would be very arbitrary to say there are nine planets, as if you include Pluto there are no grounds to exclude objects like Eris and Sedna.

Personally I support the IAU definition as it does have some descriptive power. The eight planets have a different evolutionary history to the dwarf planets: they grew big enough to sweep up and boss their orbits. However, it's certainly not perfect. We like to think of things as belonging to tidy little categories while the universe often presents us with a continuum of possibilities. How do we describe an object on the on the cusp of being a planet or a dwarf planet?

I see it as a little parable on the process of science, an idea refined in the light of better knowledge. Ultimately, Pluto doesn't care what we call it, and it makes no difference to its scientific interest. I look forward to getting a look at it in 2015, when New Horizons pays a call.

[DommyDevil18]

Don't get me wrong though I personally think that Pluto has its best days ahead in 2015 but I hope it does not get reinstated. Personally reclassifying it was a step up because it may help us understand the word Planet it might even change the definition

[trazor]

Both science and history are constantly being rewritten. That's why they both improve...

Can't argue about science being rewritten, those are factual and replace incorrect theories etc.

You can not improve history...?????

And to write Pluto off is changing History, and I can't agree, as it's based upon an arbitrary decision.

I will now introduce the Trazor planet size identifier (TPSI) for short.

To qualify as a planet, its diameter must be at least 40,000 km, thus we now only have 4 planets, Earth is now merely a lump of rock orbiting the Sun.

History rewritten on the hoof.