Is Pluto a planet or not? I saw a special on tv showing that it may not be a planet after all.
2007-01-05 12:28:29 · 25 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
The International Astronomical Union decided that Pluto was no longer a planet. The reason is that while Pluto is round, orbits the sun, and has three moons, it has not cleared (via gravity) its own orbit of debris. Instead, they decided to classify it as a "dwarf planet".
See the details below.
RESOLUTION 5A
The IAU therefore resolves that "planets" and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:
(1) A "planet" [footnote 1] 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 neighbourhood 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 [footnote 2] , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
(3) All other objects [footnote 3] except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".
Footnote 1: The eight "planets" are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Footnote 2: An IAU process will be established to assign borderline objects into either dwarf planet and other categories.
Footnote 3: These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.
RESOLUTION 6A
The IAU further resolves:
Pluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.
2007-01-05 13:40:41 · answer #1 · answered by Otis F 7 · 2⤊ 0⤋
Not any more!
"Planet" is really an invented notion, there is nothing fundemental or special about the designation, and until recently, the generally accepted definition was for a body orbiting the Sun that was as big as, or bigger than, Pluto. With improvements in telescopy, though, it has been discovered in the last few years that there are quite a number of objects (not currently recognized as planets) orbiting the Sun that are bigger than Pluto.
A committee recently concluded it was easier to "demote" Pluto than to add all the other objects as planets.
Poor little Pluto, the Rodney Dangerfield of local space!
2007-01-05 12:35:49 · answer #2 · answered by Anonymous · 0⤊ 0⤋
In August, 2,500 astronomers met at Prague, Czech Republic and decided that Pluto is no longer a planet but a dwarf planet. Doesnt exactly make any difference if you ask me. Pluto was even smaller than this Comet, and they decided that Pluto was not big enough to be a planet.
2007-01-05 12:59:08 · answer #3 · answered by Anonymous · 0⤊ 0⤋
It is a planet. For something to be a planet it needs to have 3 things. One of them, it has to be bigger than Pluto. So if Pluto is not a planet then something is wrong.
2007-01-05 12:38:44 · answer #4 · answered by Anonymous · 0⤊ 0⤋
As of August 22, Pluto is declared the planet no more
2007-01-05 12:36:20 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Its a mess isn't it?
We all learn in school that there are 9 planets then they discover something bigger and farther out than Pluto.
Drat! They argue over whether the new object is truly a planet, decide it isn't "round enough", and then criticise Pluto's shape too.
Poof! Neither one is "officially" a planet now.
2007-01-05 12:38:35 · answer #6 · answered by T K 2 · 0⤊ 0⤋
It's just a question of definition. Imagine you have a whole range of orbiting object from the size of gravel up to the size of Jupiter and Saturn. Just how big does something have to be to be a planet rather than an asteroid?
See here: http://en.wikipedia.org/wiki/Pluto#Planetary_status_controversy
And officially it is not a planet
2007-01-05 12:31:15 · answer #7 · answered by PJ 3 · 0⤊ 0⤋
itz not considered a planet anymore since they found that other planetish thingy and they didn't want it to be the 10th planet and pluto had similar characteristics so they decided that pluto shouldn't be a planet
2007-01-05 12:34:25 · answer #8 · answered by Anonymous · 0⤊ 0⤋
No, Pluto is not a planet. It is too small and its orbit is highly elliptical. It is just different from the planets.
2007-01-05 13:49:06 · answer #9 · answered by bldudas 4 · 0⤊ 0⤋
The tv show is right. It used to be a planet, but now its not anymore.
2007-01-05 12:31:40 · answer #10 · answered by Anonymous · 0⤊ 0⤋