Why was pluto banned from the solar system?

Question

I read it somewhere in a magazine

How many planets do we have next?

Answer 1

Too many drunken brawls.

Answer 2

Public intoxication. You can't trust those dwarf planets, I always say. Suspicious buggers, being all smaller than the other planets.

Well, actually, it was hardly banned. It's still out there, somewhere, all part of the solar system. The scientists just got together and decided that, once and for all, they needed a steady definition of "planet". See, "planet", "comet", "asteroid"- these are arbitrary human distinctions. In laymen's terms, calling Pluto a planet was not a problem at all. However, astronomers like to be more precise than that, much like all scientists. See, Pluto is very small and has a weird orbit. If Pluto's a planet, why aren't we including Haley's comet? It orbits the sun. There are some big freakin' rocks in the asteroid belt as well that could've been contenders. Pluto was more a planet out of habit.

Since it is patently ridiculous that Haley's comet and some of the larger asteroids are planets in the same way that, say, Jupiter is, with the more strict definitions, Pluto had to be cut as well. Now we're down to eight proper planets. Pluto now gets to be a dwarf planet. It's not even the biggest one, either. Ceres, a large body in the asteroid belt, is the largest dwarf planet. Haley's comet is still a comet because it's still a lot smaller than the dwarf planets.

Answer 3

The scientific definition of a planet was, to put it lightly, rather hazy at best until recently. In fact, there really was no definition to speak of. Pretty much anything that orbited the sun could be termed a planet if the astronomer that discovered it felt like calling it a planet.

As astronomers found more and more objects further and further out they realized that a firm definition had to be agreed on or else we'd have hundreds, if not thousands, of planets. It just so happens that the definition that was agreed upon didn't fit Pluto's attributes.

So, to answer your question, technically we now have eight planets although nearly every astronomer agrees that they still consider Pluto a planet. Officially however, it's not and it's not likely to appear on any lists in newly published science textbooks but it might get some sort of footnote stating that it was at one time considered a planet.

Answer 4

You have heard one side of a multisided scientific argument. Some astronomers have said Pluto does not qualify as a planet due to some of its characteristics - size or orbit or whatever reason . Others, last I knew, had discovered other bodies orbiting the sun that would be called planets if Pluto is also classified as one.

It is still part of the solar system. There is disagreement about what kind of body to call it, that's all.

Answer 5

designated (134340) Pluto in the Minor Planet Center catalogue, is the second-largest known dwarf planet in the solar system. It orbits between 29 and 49 AU from the Sun, and was the first Kuiper Belt Object to be discovered. Approximately one-fifth the mass of the Earth's Moon, Pluto is primarily composed of rock and ice. It has an eccentric orbit that is highly inclined with respect to the planets and takes it closer to the Sun than Neptune during a portion of its orbit. Pluto and its largest satellite, Charon, could be considered a binary system because they are closer in size than any of the other known celestial pair combinations in the solar system, and because the barycentre of their orbits does not lie within either body. However, the International Astronomical Union (IAU) has yet to formalize a definition for binary dwarf planets, so Charon is regarded as a moon of Pluto. Two smaller moons, Nix and Hydra, were discovered in 2005. Pluto is smaller than several of the natural satellites or moons in our solar system (see the list of solar system objects by radius).

From its discovery by Clyde Tombaugh in 1930, Pluto was considered the ninth planet from the Sun. In the late 20th and early 21st century, many similar objects were discovered in the outer solar system, most notably the Trans-Neptunian object Eris which is slightly larger than Pluto. On August 24, 2006 the IAU redefined the term "planet", and classified Pluto, Ceres, and Eris as dwarf planets.[1] Pluto is also classified as the prototype of a family of trans-Neptunian objects.[2][3] After the reclassification, Pluto was added to the list of minor planets and given the number 134340.


IAU Decision

Main article: 2006 redefinition of planet

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':

1. The object must be in orbit around the Sun.
2. 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.
3. It must have cleared the neighborhood around its orbit.

Pluto fails to meet the third condition. The IAU further resolved that Pluto be classified in the simultaneously created dwarf planet category, and that it act as prototype for a yet-to-be-named category of trans-Neptunian objects, in which it would be separately, but concurrently, classified.

Answer 6

They said it was too small to be a planet. It is now considered a dwarf planet. There are 44 dwarf planets in our solar system from what the article says below.

Answer 7

pluto is no longer a major planet of the solar system. yes, the other respondents put it nicely with the phrase "size matters"... pluto is small to be considered a major planet.

Answer 8

Yes we still have Pluto which makes us have 9.

Mercury, Venus, Earth, Mars, Jupiter, Saturn Uranus, Neptune, & Pluto

Answer 9

scientists were arguing if it was big enough to be a planet, and it was orbiting neptune like a moon for over 200 years soo they took it off because it was too much like a moon than a planet

Answer 10

Because size matters! :)
No one cares about the little guys.