Who says that Pluto is not a planet?

Answer 1

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 2

Well given it's size and orbit, among other things, it does not really quite match the other "planets", unless we want to start adding other objects as planets too... so the easiest way out was to drop Pluto. Perhaps this description will help clear this up:

"Our Planetary System"

Five classes of objects orbit our Sun. The inner terrestrial planets are separated from the outer gas giant planets by the Asteroid Belt. Beyond the outer planets is the Kuiper Belt of comets, a disk of small icy worlds including Pluto. Much more distant, reaching a thousand times farther than Pluto, lies the Oort Cloud of comets."

Pluto just has too many differences from planets to be considered one - that's the bottom line.

As to "who says", well the world's noted astronomers got together and had a meeting over this and other issues and decided it was best to reclassify Pluto, for reasons obvious to most but apparently NOT to chuckles82791 or whatever his name is (above). As for the "morons" crack, Mike Brown at CalTech and the members of the IAU might have something to say if he ever says that to their faces...

A clear majority of researchers voted for the new definition at a meeting of the International Astronomical Union (IAU) in Prague, in the Czech Republic. The IAU decides the official names of all celestial bodies. (I hear they held an internet vote or something - ahh democracy at work! Just think, if we decided EVERYTHING by majority vote Al Gore WOULD have been President [SHUDDER])

Answer 3

The exact names u need are :
Brain Marsden,
Dan Green
Gareth Williams
They r from Harvard Universitiy's Smithsonian Astrophysical Observatory (who operate an on-line clearing house for data concerning minor planets in the "Minor Planet Center"), argue that Pluto is not properly classified as a planet, but is better thought of as an asteroid or comet.

Reasons given by Harvard group for categorizing Pluto as an asteroid (I'm just pointing out the major reasons) :
(1)Pluto is smaller than 7 moons in the solar system.
(2)Pluto is unlike the other planets in that it has an icy surface instead of a rocky surface like the inner 4 (terrestrial) planets, or a deep atmosphere like the next 4 (gas giant) planets.
(3)Previously (in 1999), Pluto was claimed to be TNO(Trans-Neptunian Object).Later Marsden said that "Pluto has more in common with comets than it does with planets" in Atlantic Monthly.Some scienists say it's among Kuiper Belt Objects [KBO's are small bodies which orbit the Sun beyond Neptune's orbit].
(4)Recently(Aug.2006),International Astronomical Union (IAU) voted this month to redefine a planet.There is both a size limit & a requirement that the object sweep out its orbit. In addition the object must independently orbit the Sun (excluding several large moons of Jupiter). This new classification redefines Pluto as a "dwarf planet", leaving the Solar System with 8 "classical planets". New additions to the dwarf planet class are Sedna, the largest asteroid, Ceres and "Xena".

If u want further details, check out links below :
http://www.smh.com.au/articles/2003/03/09/1047144868646.html
http://curious.astro.cornell.edu/question.php?number=624
http://mips.as.arizona.edu/~stansber/Planet.html

Answer 4

Sigh. I learned the mnemonic My very educated mother just served us nine pizza pies. Planets in order from sun mercury, venus, earth, mars, jupiter saturn, uranus and pluto. Kids now can learn: My very educated mother just served us NOTHING!

Or maybe served us 2003 UB313
http://www.timeforkids.com/TFK/news/story/0,6260,1093028,00.html

Pluto is not a planet anymore. It is a dwarf planet. I am sad.

Poor, puny Pluto. After it was discovered in 1930, it basked in the glory of being named the ninth planet in our solar system. But in the years since, astronomers have debated whether Pluto truly is a planet. After all, it is smaller than other planets, has a strange tilt and travels in an odd orbit.
http://www.timeforkids.com/TFK/news/story/0,6260,1333579,00.html#

Well, scientists redefined what is and is not a planet. See the references below for details.

Answer 5

Some fool says its an asteroid. This fuels the debate over a destructive collision with earth. It could mean more work for NASA and an extension of the failed space program. It must be political and economical to do such a thing.

Answer 6

Walt Disney

Answer 7

Its still a planet to me, i think the whole things stupid...everyones been brought up to know that it is, and all of a sudden, they decide, nah, its nothing?

Answer 8

Scientists around the world.

Answer 9

Stupid....Pluto's a dog.Don't you ever watch Mickey Mouse?
I'm not sure what Goofy is ....dog face... human feet.....weird!

Answer 10

Mickey and Goofy