2006-08-29 07:42:31 · 16 answers · asked by tanjamorne 1 in Science & Mathematics ➔ Astronomy & Space
the international astronomical union defined three terms "planet", "dwarf planet", and "small solar system body". this does not change anything about the solar system or pluto. it just corrects the mistake of classifying pluto as a planet initially. i actually feel somewhat vindicated. i have known since i was about twelve that pluto did not have the physical and orbital characteristics of the major bodies in the solar system. later, after the discovery of hundreds of similar bodies in similar orbits, i knew this was inevitable.
(1) A planet is 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 neighborhood around its orbit.
(2) A dwarf planet is 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, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.
(3) All other objects orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".
because pluto orbits the sun, is round, orbits the sun with a bunch of other similar bodies with similar orbits, and is not a satellite it is a dwarf planet.
look here:
http://www.iau2006.org/mirror/www.iau.org/iau0603/index.html
2006-08-29 08:38:08 · answer #1 · answered by warm soapy water 5 · 2⤊ 0⤋
It is fair that pluto lost its status - it never really fitted neatly into the classification of other planets. Ceres (an asteroid, now considered a dwarf planet along with Pluto) used to be considered to be a planet for over 50 years until it was downgraded to an asteroid. Pluto lasted 76 years before being downgraded to a dwarf planet. If we allowed Pluto to be considered a major planet then we would end up with hundreds of "planets" orbiting the sun. At least with 8 major planets everyone can know what they are.
2006-08-30 11:15:57 · answer #2 · answered by Arimaa Player 2 · 0⤊ 0⤋
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.
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
2006-08-31 22:44:32 · answer #3 · answered by Anonymous · 0⤊ 0⤋
The IAU (International Astronomical Union) voted last week on a definition of planet. This definition requires that a planet has sufficient mass to achieve hydrostatic equilibrium (spheroidal shape), is neither a star nor a satellite of any body other than the Sun, and has cleared the neighborhood of its orbit. Pluto passes all but the last criterion, which is sufficient for it to be designated a "dwarf planet," but not a "planet." Pluto's orbit crosses those of many similar bodies, with no significant interaction, so it has not cleared its orbit. On the other hand, even though Neptune's orbit also crosses those of smaller bodies, Neptune's gravity dominates the orbit of all of those bodies, including Pluto, holding them in resonance with it.
2006-08-29 14:49:01 · answer #4 · answered by DavidK93 7 · 2⤊ 0⤋
Well, due to recent discoveries, if Pluto was kept a planet then we would have to add at least 10 other planets because they fit the definition of planet too. Anyway, Pluto is tiny and is more like an asteroid than a planet, and didn't really deserve the title of planet anyway
2006-08-29 14:48:41 · answer #5 · answered by skiiermandan 3 · 0⤊ 0⤋
they changed the definition of a planet... And pluto has always been a weird one, so it has been kicked out to leave only fully fledged planets keep the appelation of planet.
That way, the definition of a planet will be more logical, and the added bonus is that you will only have to remember 8 planet names for your next exam !!!
2006-08-29 14:45:55 · answer #6 · answered by Anonymous · 4⤊ 0⤋
Yes it is to do with the size and shape which they have now got a universal description and so Pluto is now a plutoid as will other planets of the same size and shape.
2006-08-29 15:16:11 · answer #7 · answered by weeman1971 3 · 0⤊ 1⤋
Because they have now clearly established what the the definition and criteria of what a planet is and that is one of the main facets of science new changes and dicoveries are made everyday and we just have to adapt.
2006-08-29 14:51:24 · answer #8 · answered by afrprince77 2 · 0⤊ 0⤋
It is a question of the definition of a Planet.
Pluto does not fit the new definition of "Planet".
2006-08-29 14:49:48 · answer #9 · answered by mykidsRmylife 4 · 0⤊ 0⤋
because they a bunch bastards and who cares pluto still a plantet to me and anyone else who wants it to be since pluto is my home planet
2006-08-29 14:48:53 · answer #10 · answered by michaelizdabest 3 · 0⤊ 0⤋