Do you think pluto should be considered a planet?

Question

please explain why. personally, i think it should but i'm always open to other opinions. please state your reasons. best answer will be chosen by the quality, and not whether i agree with it or not.

Answer 1

No, I believe Pluto should remain a dog in the Walt Disney comics.

Answer 2

I can see merit in both sides of the arguement.  It does somewhat come down to what you want to mean by the word planet and how comfortable you are with there being something like 100 of them in the Solar System or less than 10.

The gravitational influence criterion that rules out Pluto and probably any other body in existence beyond Neptune has arisen from the orbital dynamics community and their interest in how the Solar System came to have the distribution of bodies that it has.  The "major" planets set the basic gravitational framework and the "other" bodies get pushed, pulled and prodded into position as a result.

So at base I'm comfortable with Pluto, Eris, Ceres and their ilk not being called planets.

Answer 3

I THINK YOU FORGOT TO PRINT THAT BEST ANSWER WILL BE CHOSEN BY A VOTE... NICE SCIENCEMAN... THANKS FOR WASTING OUR TIME.

Seriously Sienceman, I have always enjoyed your answers here and this was the last thing I expected from you. This isn't quite as bad as when AgentFox admitted that he believed that the manned moonlandings were a fake so please allow me to be blunt. You well know that this question is a FAQ here. So what's up with that?

http://answers.yahoo.com/search/search_r...

The process of reclassifying objects whether it is in astronomy or geology or any other branch of science is normal and essential. Would you prefer that we call all rocks on Earth "rocks" or would it help the scientific community to subdivide rocks into what minerals they contain?? Would you prefer that all hominids be called "man" instead of Homo Erectus, Cro Magnon, Neanderthal, Australiopithicus, etc.?? Does categorization of objects help or hinder the advancement of science?

In the 1840s before people understood what asteroids were, there were 11 planets. When this number was later reduced to 7 and Neptune made it 8, the people of the 1840s didn't whine and cry about their poor little planets being taken away from them. They accepted and understood science's necessity to categorize.

When Pluto was discovered in 1930, there was a mad rush to call it a planet because France and Britain were in a political battle to be the first to discover it. Everyone was looking for the mysterious planet x that had a perturbation upon Neptune's orbit.

It was a mistake to call Pluto a planet in 1930 because it was thought to be much larger and massive than it actually is because of it's icy reflectivity. In 1930, astronomers knew nothing about the Kuiper belt as you incorrectly state in your question.

If Pluto was discovered today, it would NEVER be called a planet. Today we know that Pluto is just one of MANY objects in the Kuiper belt. Pluto is not even the largest of these. Also today we know that the mysterious pull upon Neptune was based upon improper calculations. There is no transNeptunian planet x which Pluto was hoped to be in the 1930s.

Your comparison of the Kuiper belt objects to the asteroid belt is also incorrect. While the asteroid belt is composed primarily of rock and metal, the Kuiper belt objects are composed largely of frozen volatiles (ices), such as methane, ammonia and water.

I must also correct your assumption that early astronomers knew of the Kuiper Belt. They did not. In fact, it was not until 1992 that the other KBOs besides Pluto were found to exist.

It was all a mistake. A mistake corrected in 2006. I must take strong objection to your arguement that 4% of IAU members got to vote. All IAU members have a voice. But let's not forget how democratic groups work together as one unit to solve astronomical problems and concerns. It is exactly the same beaurocratic process that other organizations follow to achieve a fair system of decision making. These systems are made up of heirarchy branches. Persons propose issues which get voted on by upper and upper divisions of the organization. It is similar to the Legislative branch of a Capitalist government. You have your City Council, Mayor, Governor, Congressman, and Senators.

It's like a Senator who represents your state making a yes or no vote on a bill and then you complain that the millions of people in your state didn't get to vote on it.

Pure nonsense. I despise it when someone says that the General Assembly authorities elected by the IAU members did not have the right to make the 2006 decision. If you disagree with me, join the IAU yourself and make your voice heard. In no way whatsoever was this decision made in closed doors by 4% of the membership. Join up and try to change all Plutoids to the status of a planet in 2009 and watch yourself become a laughing stock instead of a hero for 96% of the members.

I was a Democratic delegate to the state level. As a delegate, I polled local area residents to get their opinions. I brought these opinions up at local and district meetings. During the process of selecting state delegates, we the members read through pages of suggestions which were brought up at all previous levels and voted upon which ones we felt should and should not be campaign issues. Let's assume for the moment that you are a Democrat... You go to the voting booth on election day and believe that you are exercising your power as a voter. Wrong. You are voting on the issues that we (the delegates) have decided are the important issues. You are casting your votes on the candidates that we (the delegates) have selected to choose to place on your voting paper in the national election.

This is the common way that organizations function. If you can come up with a better way to operate these groups then go for it. Let's have 300,000,000 people get together somewhere and have them equal shares in the decision process. Nothing but pure chaos would be the result.

The IAU is not some n**i Faschist group where 4% of the members have complete control and everyone else is a mere peon who has no voice.

The IAU went over and over resolutions before they decided on the 2006 definition as the best among all other choices. They were not bought off by lobbyists who paid them some cash to demote the planet Pluto to a Plutiod. Everytime this question comes up here, I laugh at the ignorance of persons whose only claim that Pluto should be a planet is because it was called that when they were a kid. Well, it's time to grow up and dry the last sentimental tear because you can't let go of your baby blanket or for heaven sakes what will you ever do now because someone took away your mnemonic and now you will never be able to remember the names of 8 planets!

Let's show some respect to the persons of the 1840s who had the decency to understand that science is not perfect. Mistakes are made. And classifying and reclassifying plants and animals and rocks and PLANETS is a normal and required process of scientific advancement and not something to waste sentiment over.

If you want to call Pluto a planet until the day you die, that's fine. It won't hurt anything. But it is incorrect and should not be taught to your children. In fact, you might as well keep calling comets the great mysterious harbingers of death since that's what was done in the past also.

If sometime in the future Pluto is again reclassified as a KBO instead of a Plutoid, then please let's just call it a KBO and not start out with saying "Oh no... I grew up calling Pluto a Dwarf Planet and to me that's what it will always be...poor Pluto."

Let's try to show some dignity and maturity towards this topic.

I don't hear anyone coming on here saying " Oh my great great grandfather called Ceres a planet so to me that's what it will always be." Think about it.

How stupid will you feel when the first person comes on here and cries "Oh, they changed Pluto and Ceres and Makemake to Plutoids. I grew up hearing they were called Dwarf Planets and to me that's what they will always be."

Then it will be your turn to answer them.

Answer 4

Is it really such a big deal.  Anyone over the age of 15 or so will always call it Pluto because that's what they learned.  It's not like it's a life altering decision here on our planet.  Besided they'll probably make it a planet again in 20 years when some new technology shows something different.

And that looong answer..."cleared the orbit?"  How big is Pluto's orbit compared to Earth or Mars?  Maybe we wouldn't be a planet either if we had an orbit that big....cleared the orbit is a technicality in my mind.

Answer 5

my dictionary states a planet is a solid celestial body that revolves around the sun. so by definition would pluto and all the asteroids be planets? i may need to invest in an A&S dictionary.

Answer 6

This has got to be be one of the most heartbreaking questions I get asked, "Why Isn't Pluto a Planet". And I get it a lot. I was expecting that a few years after the International Astronomical Union's controversial decision, the debate would have settled down and people would finally accept it. But no, it's still a sore point for many people - Pluto is not a planet (let that sink in). In this article, I'll explain the events that led up to the decision, the current state of planetary definition, and any hope Pluto has for the future. Let's find out why Pluto is no longer considered a planet.

Pluto was first discovered in 1930 by Clyde W. Tombaugh at the Lowell Observatory in Flagstaff Arizona. Astronomers had long predicted that there would be a ninth planet in the Solar System, which they called Planet X. Only 22 at the time, Tombaugh was given the laborious task of comparing photographic plates. These were two images of a region of the sky, taken two weeks apart. Any moving object, like an asteroid, comet or planet, would appear to jump from one photograph to the next.

After a year of observations, Tombaugh finally discovered an object in the right orbit, and declared that he had discovered Planet X. Because they had discovered it, the Lowell team were allowed to name it. They settled on Pluto, a name suggested by an 11-year old school girl in Oxford, England (no, it wasn't named after the Disney character, but the Roman god of the underworld).

The Solar System now had 9 planets.

Astronomers weren't sure about Pluto's mass until the discovery of its largest Moon, Charon, in 1978. And by knowing its mass (0.0021 Earths), they could more accurately gauge its size. The most accurate measurement currently gives the size of Pluto at 2,400 km (1,500 miles) across. Although this is small, Mercury is only 4,880 km (3,032 miles) across. Pluto is tiny, but it was considered larger than anything else past the orbit of Neptune.

Over the last few decades, powerful new ground and space-based observatories have completely changed previous understanding of the outer Solar System. Instead of being the only planet in its region, like the rest of the Solar System, Pluto and its moons are now known to be just a large example of a collection of objects called the Kuiper Belt. This region extends from the orbit of Neptune out to 55 astronomical units (55 times the distance of the Earth to the Sun).

Astronomers estimate that there are at least 70,000 icy objects, with the same composition as Pluto, that measure 100 km across or more in the Kuiper Belt. And according to the new rules, Pluto is not a planet. It's just another Kuiper Belt object.

Here's the problem. Astronomers had been turning up larger and larger objects in the Kuiper Belt. 2005 FY9, discovered by Caltech astronomer Mike Brown and his team is only a little smaller than Pluto. And there are several other Kuiper Belt objects in that same classification.

Astronomers realized that it was only a matter of time before an object larger than Pluto was discovered in the Kuiper Belt.

And in 2005, Mike Brown and his team dropped the bombshell. They had discovered an object, further out than the orbit of Pluto that was probably the same size, or even larger. Officially named 2003 UB313, the object was later designated as Eris. Since its discovery, astronomers have determined that Pluto's size is approximately 2,600 km (1,600 miles) across. It also has approximately 25% more mass than Pluto.

With Eris being larger, made of the same ice/rock mixture, and more massive than Pluto, the concept that we have nine planets in the Solar System began to fall apart. What is Eris, planet or Kuiper Belt Object; what is Pluto, for that matter? Astronomers decided they would make a final decision about the definition of a planet at the XXVIth General Assembly of the International Astronomical Union, which was held from August 14 to August 25, 2006 in Prague, Czech Republic.

Astronomers from the association were given the opportunity to vote on the definition of planets. One version of the definition would have actually boosted the number of planets to 12; Pluto was still a planet, and so were Eris and even Ceres, which had been thought of as the largest asteroid. A different proposal kept the total at 9, defining the planets as just the familiar ones we know without any scientific rationale, and a third would drop the number of planets down to 8, and Pluto would be out of the planet club. But, then… what is Pluto?

In the end, astronomers voted for the controversial decision of demoting Pluto (and Eris) down to the newly created classification of "dwarf planet".

Is Pluto a planet? Does it qualify? For an object to be a planet, it needs to meet these three requirements defined by the IAU:

    * It needs to be in orbit around the Sun - Yes, so maybe Pluto is a planet.

    * It needs to have enough gravity to pull itself into a spherical shape - Pluto…check

    * It needs to have "cleared the neighborhood" of its orbit - Uh oh. Here's the rule breaker. According to this, Pluto is not a planet.

What does "cleared its neighborhood" mean? As planets form, they become the dominant gravitational body in their orbit in the Solar System. As they interact with other, smaller objects, they either consume them, or sling them away with their gravity. Pluto is only 0.07 times the mass of the other objects in its orbit. The Earth, in comparison, has 1.7 million times the mass of the other objects in its orbit.

Any object that doesn't meet this 3rd criteria is considered a dwarf planet. And so, Pluto is a dwarf planet. There are still many objects with similar size and mass to Pluto jostling around in its orbit. And until Pluto crashes into many of them and gains mass, it will remain a dwarf planet. Eris suffers from the same problem.

It's not impossible to imagine a future, though, where astronomers discover a large enough object in the distant Solar System that could qualify for planethood status. Then our Solar System would have 9 planets again.

Even though Pluto is a dwarf planet, and no longer officially a planet, it'll still be a fascinating target for study. And that's why NASA has sent their New Horizons spacecraft off to visit it. New Horizons will reach Pluto in July 2015, and capture the first close-up images of the (dwarf) planet's surface.

Space enthusiasts will marvel at the beauty and remoteness of Pluto, and the painful deplaneting memories will fade. We'll just be able to appreciate it as Pluto, and not worry how to categorize it. At least now you know why Pluto was demoted

Answer 7

In the 1850s, there were 12 planets:

Mercury, Venus, Earth, Mars, Ceres, Pallas, Juno, Vesta, Jupiter, Saturn, Uranus and Neptune.

Then astronomers, using better telescopes, began to discover dozens of "planets" between Mars and Jupiter,  on orbits similar to that of Ceres, Pallas, Juno and Vesta.

Decision:  Do we increase the list of planets to hundreds (there are now millions) or do we make a new rule.

B

The smaller bodies between Mars and Jupiter were reclassified as "minor planets" (they are all smaller than our Moon) and called "asteroids" -- because they looked like stars (points of lights) instead of planets (disks) in telescopes.

Same thing happens again.

When Pluto was alone (and thought to be big), it was OK as a planet.  Now, we are discovering more and more similar objects on similar orbits.  Plus, it turn out that Pluto is smaller than our Moon.

So:  same decision as in the 1850s.  Create a new class of objects in which to lump together similar objects.  Since they are bigger than Ceres, let's call them something else:  "dwarf planets".  Also, the word "asteroid" is restricted to objects inside the orbit of Saturn.  So, we could try a different word (e.g., "plutoid" was tried but dropped)

Either way, the textbooks have to be rewritten:  either with one less planet or dozens of new planets (within a decade).

Answer 8

Pluto is not a planet - deal with it.

It is a Dwarf planet and a Kuiper Belt Object.

The International Astronomical Union defined a planet in 2006. Prior to then, we did not have a definition for planets. The planets out to Saturn are visible without a telescope, so have always been known. Consequently we didn’t have a definition for a planet before!

Ceres, the largest asteroid and the first to be discovered was originally classified as a planet, and kept this status until we discovered that it was just the largest of a class of objects we now call asteroids.

Pluto was only discovered in 1930 and it is now clear that it is actually the largest of a class of objects we now call Kuiper Belt Objects.

Consequently we now have a new class of objects called Dwarf Planets, which included Pluto and Ceres, but should also include Eris, Quaoar, and Sedna as well as several objects that are currently unnamed (they have numbers) and maybe a couple of other asteroids.

If you want to keep Pluto as a planet, you need to promote Ceres back to planet status, and you need to promote the other Dwarf Planets - necessitating textbook re-writes anyway.

Since the Kuiper belt is where many comets from, we might class Pluto as a proto-comet.

You can download my powerpoint presentation from: http://stardust.astro.missouri.edu/FTP/

the file is called: Pluto_talk.ppt

(original – huh?)

Now- to the people who say things like "My teacher told me so" or "we have to re-write the textbooks". These are ridiculous arguments.

Science is a dynamic field and our understanding of the physical universe is changing all the time.

Science books do get updated fairly regularly, and even then they are out of date within a couple of years!

Teachers (even Professors) are not always correct.

When I was a kid (before the Voyagers) Jupiter had 13 moons; shortly thereafter we found some more, so by the time I went to college it had 16 moons. Now we know it has close to 60!. Should we deny the existence of these moons in order to make "what my teacher taught me" and my old textbooks correct?