Why did the scientists cancel 'thePluto' among the nine planets?

Answer 1

If the did not "demote" Pluto, that opened the door for pretty much anything that's round to be called a planet, regardless of size. Pluto fits the accepted definition of a Kuiper Belt Object much better than it fits the definition of planet. If it remained a planet, there were potentially dozens of KBO's that would have to be designated planets as well. All those other objects you named would have been just the first of many, many new "planets." It makes sense. Even when Pluto was discovered in 1930 debate raged over whether to classify it as a planet, due to it's size and elliptical, off-kilter orbit and that was long before astronomers even knew the Kuiper Belt (with all its Pluto-like objects) existed. So, anyway, today astronomers created a new class of objects called "dwarf planets," of which Pluto is the first. There will eventually be dozens of these, I'm sure, since they have already found one object (UB313 aka Xena) that is larger than Pluto and several other objects smaller than Pluto that fit the dwarf planet description.

Answer 2

: Pluto lost its designation as a planet because it is not the dominant object in its region of space, according to new guidelines endorsed by the International Astronomical Union. Pluto's peculiar orbit overlaps with that of the much-larger Neptune, and it is one of thousands of icy bodies in the Kuiper Belt, a region in the outer solar system. Under the new definition, a planet must be a round object that orbits the sun and must dominate its neighborhood.
There have been nine ever since Pluto was discovered in 1930 at the Lowell Observatory in Flagstaff by a 24-year-old astronomer named Clyde Tombaugh.
It was bad enough on Thursday when the International Astronomical Union declared that Pluto, Arizona's singular contribution to the solar system, was no longer worthy of being called a planet. Since the 1990s, scientists have discovered dozens of Pluto-like objects in the Kuiper Belt, all smaller than Pluto. But it wasn't until astronomer Michael Brown at the California Institute of Technology spotted the larger Xena that scientists wrestled with what to call it. That forced the scientists to rethink Pluto's status.

Answer 3

It is because its low mass, and because of the high eccentricity ( eccentricity is a property of a conic section, such as an ellipse, or a parabola, for example ) of its orbit.

This is not something to get so emotional about. Scientic progress occasionally negates - with good reason and not whimzically - a result or a theory that it has held in the past. An example is Einstein's theory of relativity which changed Gallileo's view of the world and made Newton's laws only approximately true. Gallileo himself helped to change the view that earth is the center of the solar system.

So relax, and understand the science behind all this.
Besides, after all it is only the Pluto, the Earth has not been dabarred from the planet membership - not yet any way. ...

Answer 4

They redefined the definition of what a planet is and now Pluto does not fit in those guidelines. One reason was its size and the other reason is that Pluto's orbit crosses over and passes Neptune's orbit. For some reason that makes Pluto's orbit not make the right kind of independent rotation around the sun. All I know is teachers are screwed! We can't use the "My Very Eager Mother Just Served Us Nine Pizzas" now!!!

Answer 5

As the Pluto is in the form of gas & having very little mass, it is far away from Sun. Pluto, as it rotate arround the sun it get pulled by Neptune & hence it keeps on changing its orbit. It actually has an orbit like an commet. at times it comes so close to Neptune that it can even colloide with it. & hence scientists are probably describing Pluto as Drawf Planet.

Answer 6

There's the scientist's definition and the colloquial/historical.

Historically, Pluto was probably classified wrongly, which if we want to get history right we should respect that.

Scientists need a consistent definition to do their work.

We could define a class called the "classical planets" which includes pluto.

Answer 7

interesting question, its basically because scientists have been desparately trying to get a clear cut defination for 'planets' now.

And now they discovered they didn't know much. They were a few days ago, trying to add 3 more planet and now this. what the hell !!

What about the school books we read... was the entire time we were reading science (physics especially) wasted????!!

TO THE SCIENTISTS: MAKE UP YOUR MIND MAN !!!

Answer 8

Because it is actually in the oort cloud .And they think it's too small to be a planet .
They are wrong .
Many astronomers do agree Pluto should never have been called a planet. It should be one because it goes around our sun like the other planets .
I think it's ridiculas to cut out Pluto.
BIG mistake .

Answer 9

Because they foolishly refused to take historical considerations into account. The definition of 'planet' is arbitrary anyway. These scientific snobs could just have easily decided to take historical considerations into account, but decided not to.

We are under no obligation to follow their lead. Join the rising revolt against such snobbery and keep calling it a planet!

Answer 10

Probably because it was just too small & it's orbit is too irregular. Pluto has always been kind of a marginal planet anyway- so I'm not too surprised they recatagorized it as a "dwarf planet" (one of 3 or 4- I believe).