why Pluto is not a planet?

Answer 1

too far away closer to another galaxy I think

Answer 2

(m)

Pluto has been known as the ninth planet of our solar system since it was discovered by Clyde Tombaugh at Lowell Observatory in 1930. On the other hand, it has been clear for decades that Pluto does not fit in with the pattern of the other planets. Over the last few years, the accumulated information on Pluto and the discovery of an increasing number of other objects in the outer solar system with orbital characteristics very similar to those of Pluto have been discussed within the community of astronomers called "minor-planet researchers". The question of the official status of Pluto has recently come to the forefront because the orbits of some of these other objects are now sufficiently well determined that it is reasonable to begin including them in the catalog of orbits of what are now generically known as "Trans-Neptunian Objects" (TNOs).

IAU Division III has already recommended that Pluto be included as number 1 in a catalog of TNOs.

Does this mean that Pluto has been demoted? The answer is no. Pluto will have dual classification as a planet and a TNO, at least for the time being.

Currently, the definition of a planet (as opposed to an asteriod or a TNO) is rather arbitrary. If astronomers reach a consensus on what the defintion of a planet should be, then IAU may reclassify some Solar System objects. However, in the absense of such a consensus, the definition is historical and arbitrary; moreover, many people outside the professional astronomy community have an interest in this issue, as the media attention attests. "Until there is a consensus that one of the physical definitions is clearly the most useful approach in thinking about the solar system, the IAU will not 'demote' Pluto or 'promote' Ceres," says the IAU.

Answer 3

Is Pluto a planet???? Yes and no...

Well for starters, Pluto is just too small. In the neighborhood where Pluto lives? Planets are supposed to be huge. The Jovian planets, Jupiter, Saturn, Uranus and Neptune are 20 to 300 times the size of the Earth, and Pluto is really small compared to the Earth, smaller than our Moon. Kind of stands out.

And Pluto is not made out the same material as the Jovians. The large planets are mostly gigantic spheres of gas, mostly hydrogen and helium. Likely there are no solid surfaces, only denser and denser gas all the way in. Pluto is a small solid world of methane, water, carbon dioxide and ammonia ices, maybe a little rock and with a just hint of atmosphere (that freezes out and falls as snow in her "winter").

And third, Pluto's orbit is the most eccentric (oval shaped) and the most tilted to the plane that the rest of the planets orbit in. Also, Pluto is locked in a resonance with Neptune's orbit and comes closer to the sun than Neptune sometimes.

There were theories that Pluto was a lost moon of Neptune but that was before we discovered she a has one large moon (Charon) half her size (pretty much, this system is a double planet) and recently two other teeny-tiney moons (Nix and Hydra).

Pluto seems like she cant be an ejected moon-she must have formed on her own and seems to be part of an entire army of small icey-dwarf objects that circle just outside Neptune's orbit in what is known as the Kuiper belt. We have no idea of how many or how large these objects may be, hundreds???? NOT "planets" proper, hence the new term "dwarf planet" where Pluto is king.

But... I still think Pluto SHOULD be called a planet because of historical reasons (discovered by an American, financed by Percival Lowell, Tombaugh's life story, etc).

Answer 4

This is how it started: if we were to keep Pluto as a planet we would have to call Eris (a recently discovered larger than Pluto object) a planet too. As well as all other objects larger than Pluto that were going to be discovered within the same area in the future, they should also be called planets too.

Add to this the tiny size and mass of Pluto (as opposed to the huge sizes and masses of the giant planets surrounding it), its eccentric orbit (suggesting it is a captured asteroid, probably captured by Jupiter some time in the Solar System's past) and its terrestrial nature (also suggesting its asteroidal nature).

For all these reasons Pluto has recently been reclassified to a dwarf planet. Also the other object I mentioned before, Eris, that's now considered a dwarf planet too.

Answer 5

Pluto continues to be designated a Planet by the International Astronomical Union, which is the only body of astronomers on this planet that has the final say in designating astronomical objects.

The problem is that there is very strong interest in providing Pluto with a dual classification because it shares many of the same properties with the recently discovered trans-Neptunian bodies. Historically, there are several presidents for such a dual classification. The minor body Chiron, for example, was initially claimed to be the Tenth Planet, but subsequent studies showed it to be a distant asteroid. Still, it has a distinct coma so it is also classified as a periodic comet among the nearly 10,000 minor bodies with known orbits.

Pluto is a large body and is rightly identified as a planet on this basis alone, with a radius of about 1,700 kilometers. However, in 1996 another large body was discovered beyond the orbit of Neptune, but now has the temporary designation 1996TL66. If one assumes an albedo of about 4%, the radius of this object is some 250 kilometers. There are many dozens of other smaller trans-neptunian bodies that are also known, and this has led the International Astronomical Union to investigate whether Pluto should receive a dual classification as a Planet and as a trans-Neptunian body. It would be the largest of this new population ever detected, and historically the first one discovered.

This does NOT mean that it would be stripped of its classification as a planet, only that it would be the only planet that would also be listed among the minor bodies of the solar system with a designation number near 10,000. The subsequent trans-Neptunian bodies would receive permanent designations beyond number 10,000, so that whenever an astronomer pulls-up a list of these bodies, Pluto would always appear first in the list with the lowest designation number

Answer 6

ACCORDING TO THE NEW DEFINITION,PLANRT IS DEFINED
AS THE:
1)SELF SUSTSANABLE PLANET WHICH HAS IT'S SELF-SUFFICIENT GRAVITY

2)SUFFICIENT HYDROSTATIC PRESSURE.

3)THE RADIUS OF THE PLANET SHOULD NOT EXCEED 1490 KM)
{EXCEEDS 1600 KM}

IF A CELESTIAL BODY POSSESES ALL THE ABOVE 3 CONDITIONS IT IS CONSIDERED AS A PLANET.

BUT PLUTO DOES NOT POSSESS ANY OF THE ABOVE CONDITIONS

HENCE IT IS NOT CONSIDERED AS PLANET.
BUT IT IS CONSIDERED AS A DWARF PLANET.

ANOTHER REASONS
Pluto as a planet?THEN
we would have to call Eris (a recently discovered larger than Pluto object) a planet too. As well as all other objects larger than Pluto that were going to be discovered within the same area in the future, they should also be called planets too.

Add to this the tiny size and mass of Pluto (as opposed to the huge sizes and masses of the giant planets surrounding it), its eccentric orbit (suggesting it is a captured asteroid, probably captured by Jupiter some time in the Solar System's past) and its terrestrial nature (also suggesting its asteroidal nature).

For all these reasons Pluto has recently been reclassified to a dwarf planet. Also the other object I mentioned before, Eris, that's now considered a dwarf planet too.

Answer 7

Pluto's radius is around 1490 km. But according to a new decision bu Astronomer's union, celestial objects with radius less than 1500 km cannot be considered as planets. Also, its orbit is highly eccentric and it ventures in Neptune's orbit for a long time. Hence, Pluto is no longer a planet.

Answer 8

now you know that Pluto and Neptune are the only planets who's orbits Cross each other! scientists discovered that Pluto was not right in its path and this is what happened! Pluto went in to the orbit of Neptune's and lost all its hydrogen and helium! those gases which made him a planet! Pluto lost all its gases and became a white dwarf! white dwarf means a celestial body(celestial means that any thing that belongs to space) which looses all its gases!

Answer 9

because pluto is too small to be a planet. pluto is like the other small space things. pluto is different with jupiter, saturnus, uranus, and neptunus. it didn't compottity by gas

Answer 10

not much of pluto is known. it is not considered as a planet now bcoz it aws found ot be passing the orbit of neptune and also bcoz it is said to have been smaller than one of the satellites of neptune

Answer 11

because is not enough big to be a planet, a "there are 3 categories for it: planets, dwarfplanets, and everiting else.

now puto is a "dwarfiplanet"

that sucks !!!!!!!