Why is Pluto not classed as 'in our solar system' anymore?

Answer 1

According to the new definition, a full-fledged planet is an object that orbits the sun and is large enough to have become round due to the force of its own gravity. In addition, a planet has to dominate the neighborhood around its orbit.

Pluto has been demoted because it does not dominate its neighborhood. Charon, its large "moon," is only about half the size of Pluto, while all the true planets are far larger than their moons.

In addition, bodies that dominate their neighborhoods, "sweep up" asteroids, comets, and other debris, clearing a path along their orbits. By contrast, Pluto's orbit is somewhat untidy.

Pluto will now be dubbed a dwarf planet.

But it's no longer part of an exclusive club, since there are more than 40 of these dwarfs, including the large asteroid Ceres and 2003 UB313, nicknamed Xena—a distant object slightly larger than Pluto discovered by Brown last year.

Answer 2

First of all, Pluto is still classified as in the solar system.
After all, it is in orbit around the sun. But it is not
classified as a planet anymore. Recently several more
orbital bodies within the solar system have been found.
And if we called Pluto a planet then we would have to call the new ones planets also. These new ones are in a solar orbital area referred to as the Kuiper belt and there maybe hundreds of bodies like Pluto out there. Well
the world astronomical group wanted to preserve
the meaning of the word "planet" to be something special,
so they altered the definition so that it would exclude the
Kuiper belt bodies which also excluded Pluto.
Pluto has always been a litle different. The small solid
planets, Mercury, Venus, Earth and Mars are closest to
the sun and the gaseous giants, Jupiter, Saturn, Uranus
and Neptune are farther. Then farther out is Pluto, a small rocky body. Poor Pluto. He's out of place. Pluto also
has an elliptical plane that is not in the same plane as the
proper planets.

Answer 3

Pluto is in our solar system. That has not changed.
What has changed is that Pluto is no longer considered a planet.
When it was discovered, it was thought to be much larger. However, it was learnt that Pluto has a close moon, Charon.
At the extreme distance that Pluto is from Earth, it was originally thought to be one object, not two. It turns out that Pluto is only 1/5th the mass of Earth's moon. Not much of a planet. Also, Charon is almost the same size, so calling it a moon to such a small object is not very accurate. Also, Pluto is smaller than several of the other moons in our solar system.

So, realizing how small Pluto is, and needing some criteria to go by, in August of 2006 the International Astronomical Union redefined "planet" and reclassified Pluto as a 'Dwarf Planet"

So Pluto is still in our solar system, it has just been demoted.

Answer 4

It has been demoted from planetary body to captured asteroid/comet. Pluto has an irregular orbit and spin in comparison to the other planets. Our solar system began when the sun was exploded into existance from what is known as an accretionary disc - a mass of material that spun and aquired greater mass and heat. The material blown out into space formed the planets - the lightest and most volatile materials such as the gases, blew furthest away (but still under the gravitational pull of the newly formed sun) and formed the gas giants. The denser rockier material formed in this explosion formed the inner planets. Because they are all formed from the same event, they generally have the same orbital path - Pluto is an anomoly. It is now agreed that pluto is probably a stray body pulled in by the gravitational field from the solar system.

Answer 5

Maybe because it is so close to the outer rim. There is a belt of debris at the edge of our system which pluto is now a part of. It is not a planet so this alter the boundry and makes our solar system slightly smaller. Its nice to have a cosey little system in this vast space, is it not?

Answer 6

Pluto has been 'declassified' from a planet to a dwarf plant as IAU (international Astronomical Union) re-jigged the way it classifies planets. Under the new 'rules', Pluto is a) too small b) not speherical enough. It's not spherical enough because its gravitational force isn't strong enough to make it perfectly round.

Answer 7

Holst wrote his Planets Suite before the discovery of Pluto, so only wrote 7 peices for Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune (he ignored Earth). A few years ago sombody decided to complete the set by composing a piece named Pluto, but it now seems the joke is on them, doesn't it ? ;o))

Answer 8

Poor Pluto, it got demoted, now it is a planetoid,
so as a planet it does not exist anymore. I for one,
think that it is disgraceful,I think it is a Walt Disney conspiracy, they wanted their dog represented by a better and bigger planet.Astronomy is going to the dogs, as soon as Mercury gets hit by the car lobby , I am putting a formal protest.

Answer 9

It's still classed as "in our solar system", just not as a planet, since they've decided it's too small.

Answer 10

scientist are thick, firsdt they call it a planet for donkey yesras, then not.. its like me saying to u, ure a good human, then after 5 years out of the blue moon, satying ure an animal, makes no sense.