what is the reason why pluto was excluded from the major planets of the solar system?

Question

the article about it

Answer 1

pluto is not a planet, but pluto orbits the sun, is round, does not have an isolated orbit (a bunch of other similar bodies have similar orbits.), and is not a satellite so it is a dwarf planet. this does not change anything about the solar system or pluto. it just corrects the mistake of classifying pluto as a planet initially.

this same thing has happened before. beginning in 1800, astronomers found a few bodies orbiting between the orbits of mars and jupiter, and they finally stopped calling them planets after the fourth discovery. 150 years from now, no one will think of "134340 pluto" as a planet. very few will even know we classified it as a planet.

i have been waiting for this since i was about twelve. i feel somewhat satisfied. i knew that pluto didn't fit the pattern set by the major bodies in the solar system so it was an anomaly. it just felt illogical and "out of place". this was the right thing to do, believe me. i don't understand why so many are having such a problem with this.

i don't know how long this will drag on tho. many planetary scientists are not satisfied that the definition is rigorous enough.

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

Answer 2

Pluto, the last planet to join the heavenly pantheon, became the first to leave it. The status of Pluto had been under discussion for some time, but with the discovery of 2003 UB313, nicknamed Xena, the question became acute, for it seemingly had as much right as Pluto to be called a planet.

On August 24, 2006, the International Astronomical Union surprised the world by voting in a new definition of planet, one that would exclude Pluto and bring the total number down to eight. (There had previously been been strong speculation that the redefinition would bring the total up to 12 instead of down.)

Pluto was instead classified as a dwarf planet, along with Ceres and the aforementioned Xena. The main difference between a dwarf planet and the real thing is that the dwarf variety has not cleared the area of its orbital path.

This redefinition met with a wave of protests from those who wanted to see the ninth planet grandfathered in, including but not limited to supporters of the late Clyde Tombaugh, who discovered Pluto in 1930. His widow, however, said he would have been accepting of the IAU's decision since "he was a scientist" and understood that astronomers had to take into account newly discovered objects in the Kuiper Belt (where Pluto is located).

But opponents of Pluto's demotion remain unconsoled and have generated a thriving industry in T-shirts, mugs and other memorabilia. Among the many slogans of this movement was one which played on the mnemonic for the names of the erstwhile nine:

Answer 3

Why? Because it's NOT a planet. We've known that for awhile now, they're just now getting around to taking it off the list.
Pluto is a comet. Unlike the 8 planets, its orbit is highly elliptical, highly eccentric, it is composed of ices (just like all of the other comets) whereas all of the planets are either rocky and terrestrial (inner planets) or gas giants (outer planets). If you put Pluto as close to the Sun as the Earth is (or not even that close) it will sublime gas and grow a coma and tail just like every other comet does.
6 months ago I told my students "within 5 years Pluto will be stripped of its planetary status". I had no idea I'd be that right that soon.

Answer 4

The main reason is because of its size and the fact that they found three new planets in range of our solar system that made them change their mind. Ceres, Charon, Xena, these are the new planet names. Also the reason was because Pluto was drifting to far out from the solar boundary. I mean it is still consider a planet in a way but not a part of our solar systems expectations.

Answer 5

Pluto should have always been excluded from the list of planets due to the fact that it doesnt follow the properties and characteristics of the "jovian" planets that preceed it. From Jupiter to Neptune, these planets all are gaseous planets with large masses, liquid gas surfaces, and solid "moons" that orbit them (as well as rings on most). These planets also orbit the sun in "regular and predictable" paths. Pluto is a solid/frozen entity, whose orbit around the sun is "irregular". Last info I saw on the subject was Pluto now has the classification of "dwarf planet" which now redefines the titles of the other heavenly objects that travel through our galaxy such as Ceres! Stay tuned as the mystery continues to unravel, and text books/posters/etc begin to be republished as the "eight planets" so far. I hear from the astronomy circles that two more "planets await to be named?!

Answer 6

The IAU members gathered at the 2006 General Assembly agreed that a "planet" is defined as a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

Pluto fails criterion (c) because it has many neighbors of similar mass.

This means that the Solar System consists of eight "planets" Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. A new distinct class of objects called "dwarf planets" was also decided. It was agreed that "planets" and "dwarf planets" are two distinct classes of objects. The first members of the "dwarf planet" category are Ceres, Pluto and 2003 UB313 (temporary name). More "dwarf planets" are expected to be announced by the IAU in the coming months and years. 

Aloha

Answer 7

Pluto was excluded from the solar system because: A. Scientists have found a meteor bigger than pluto and B. Pluto was sharing Neptunes gravitational pull.

Answer 8

I think the reason was that some scientists found that Pluto was smaller then they thought. But its very tricky to define a planet by its size alone. I think that the recent definition is pretty arbitrary.

Answer 9

The science community has again changed their minds on what constitues what makes a planet and Pluto fell just short of that and was reclassified a "dwarf planet"!! Absolutely insane if you ask me!!

Answer 10

It was too small and it was because it really isn't a planet but a huge rock. It's smaller than the United states...