the IAU (international astronomical union) met in Prague last year and decided upon a specific definition for a planet,
for a space object to qualify as a planet, it has to:
1-orbit the sun
2-have a nearly round shape
3-be dominant enough to clear its orbit
pluto doesn't apply with the third condition so it has been classified in a new space group called "dwarf planets"
2007-04-07 04:38:36
·
answer #1
·
answered by 2011 1
·
0⤊
0⤋
because In the late 20th and early 21st centuries, many objects similar to Pluto 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 defined the term "planet" for the first time. This definition excluded Pluto, which was then reclassified under the new category of dwarf planet along with Eris and Ceres. Pluto is also classified as the prototype of a family of trans-Neptunian objects
2007-04-07 04:38:44
·
answer #2
·
answered by Lai Yu Zeng 4
·
0⤊
0⤋
Personally, I just think the astronomy group wanted to get noticed.
It is really irrelevant whether Pluto is or is not a planet....to me....I will never go there in my lifetime so it has no effect on my daily living. That also applies to the rest of them. Taking it out of the solar system equation seems just as stupid too. I have even less interest in studying astronomy now.
Who is making up the rules?
2007-04-07 04:38:03
·
answer #3
·
answered by ButwhatdoIno? 6
·
2⤊
0⤋
In the past, Pluto used to satisfy the criteria of what constitute a planet. Recently, astronomers changed these criteria, and apparently Pluto does not satisfy the (new) requirements, and hence it's no longer a planet.
Read this for more info:
http://www.space.com/scienceastronomy/060824_planet_definition.html
2007-04-07 04:38:10
·
answer #4
·
answered by Astroboy 2
·
0⤊
0⤋
It is too small; smaller than the Moon. We actually didn't know that until just a few years ago. Previously it was estimated to be larger than Mars. The reason we didn't know the size before is that it is so far away that we cannot see it as more than a point of light. It presents no measurable disk. We got a good measure of its size only when it passed in front of a star allowing us to time how long the star was covered and so calculate an exact size.
2007-04-07 05:28:22
·
answer #5
·
answered by campbelp2002 7
·
0⤊
0⤋
too small, it's smaller than our moon...if we considered Pluto a planet than we'd have to consider about 20 other chunks of rock planets as well.
2007-04-07 04:37:31
·
answer #6
·
answered by Paulien 5
·
0⤊
0⤋
it is a large Kuiper-belt body. The Kuiper belt is like another asteroid belt (though more composed of ice) beyond Neptune.
Pluto's orbit is wrong to be a planet, as it is not along the same plane other planets are. It is in the wrong place to be a planet that is made of rock (ice).
2007-04-07 04:37:32
·
answer #7
·
answered by Mottled Dove 2
·
0⤊
0⤋
cos there could be more Pluto at the outer ring of the solar system that we do not see yet
2007-04-07 04:38:28
·
answer #8
·
answered by kimht 6
·
0⤊
0⤋
Actually, it is STILL a planet. It is now classified as a "dwarf planet'. If a small person is classified a dwarf, is he/she still not a person?
2007-04-07 05:31:33
·
answer #9
·
answered by Bruce D 4
·
0⤊
0⤋
It is too small. Smaller than out moon.
2007-04-07 04:33:56
·
answer #10
·
answered by jomcgre3 3
·
0⤊
0⤋