Should Pluto Be A Planet?

Of course Pluto should be a planet - or if isn't, nothing should be called a planet. Earth is far more similar to Pluto in that they are both rocky than it is to the gaseous Jupiter and yet there is no call to change Jupiter's status as a planet.

I read an interesting article that mentioned a reclassifcation of all the planets to terrestrials (rocky planets like Earth) to Jovians (gas planets) and other classification for the ones similar to Pluto. That at least tries to address that their are different types of planetary objects but when it comes down to it that is all that they really can be collectively called.

Every one of the standard bodies (not including the ones we don't really understand like quasars and pulsars) in the galaxy is a collection of matter. It is all different types of matter (all the elements are represented in various proportions) and the matter is in different states (from solids to plasma) but that is all they are, a lot of matter that is joined together by its gravity or circumstance.

Bodies that are very very large and made of hydrogen become stars and it is just their size that creates the nuclear reactions that fuses the hydrogen into helium and fueling their energy output. If the collections of hydrogen are smaller (like Jupiter) then their is not the density to set off the fusion explosions to light it up like a star. If Jupiter had been much bigger then it would have been a small star itself and then we'd really have trouble defining what a planet is (although with the presence of another star in the system we probably wouldn't exist if it had). The rocky planets are bits of more solid matter that has coelesced into solid spherical balls. These smaller planets don't have nearly the density to drive any nuclear reactions so they are mostly dead except for in their slowly cooling cores where the density and friction some emit heat energy. Objects like asteroids or comets are just smaller pieces of matter that coelesced or were bigger objects that were just smashed up.

And all of these cellestial bodies interact in different ways but chiefly through gravity.

Gravity is a very weak force but it works over enormous distances and it affects every other thing. One object exerts a pull on another object which is defined by the relationship of the sum of the masses of the two bodies divided by the square of the distance between the two objects.

When one object is said to be orbiting another object they are really just orbiting each other it is only that bigger object has greater mass and therefore a greater iinertia to be overcome than the smaller. If the two objects are of the same size are in proximity then they will just spin around each other equally.

The Earth spins around the Sun but they are really just spinning around each other; the Moon spins around the Earth but they are just spinning around each other. Even Halleys Comet is orbiting the sun in it's own distinct non spherical way.

The very thing that gave Pluto's position up was that astronomers calcuated that it must be there because of the disruption to the orbits of Neptune and Uranus that could only be accounted for by the presence of a largish cellestial object.

Pluto and Mercury are a pretty similar size. The only thing that really seperatts them is distance from the sun. Mercury is much closer and therefore has a much stronger gravitational force working on it than Pluto. The two planets are still interacting gravitationally with same star and they are also interacting gravitationally with each other. The gravitational force working between them is extremely weak because of their small size and enormous distance but the force is still there. In terms of the other small planetoids such as Xena and the other Kuiper Belt objects the only difference is that they are slightly smaller (bigger than Pluto though) and further away. There is no qualitative difference between them, just quantitative. They still interact through gravity with the sun and with each other, just to a lesser degree.

There are millions of objects in the solar system. There is one very big thing which is the sun and there are few pretty big things like the gas giants and their are smaller things like the rocky planets and even smaller things like planetoids and smaller things like asteroids but they are all just things and it's just their size that differs. There is no absolute distinction we can make between any of them that will require an arbitrary decision from the astronomer's club so I think we shouldn't make that distinction.