Just some conventions but we already define what is a continent and what is a island (difined by size), we know what is a moon, etc. but, what is a planet? How do we distinguish between a planet and a simple “rock” in the space? Do we have a 10th planet or not?
What do YOU think?
Here’s a interesting link about the “10th planet“:
http://news.bbc.co.uk/2/hi/science/nature/3511678.stm
Pluto was discovered in 1930, so 74 years ago. About the status of planet, the problem of classification is that some physical reason must be used, and not just arbitraty criteria such as “size” or “orbiting a star”. In other words, a physical-based classification for ‘planets’ would say something about the formation processes, initial physical conditions, etc.. all kind of information which is really important for solar system studies.
Categories is just a thing defined by men to group other things that have something in common so people don’t waste time communicating, but it does NOT mean that it has to have EVERYTHING in common. Pluto might have similar characteristics of the other “planets”, as we define the word itself to be, and others that don’t quite fit our definition. The question is, who cares? The answer is, only the public cares. They NEED a word. But the truth is that each of the planets have many different characteristics that the only right thing to do would be to call them only by their names.
But we also have 10,001 (i don’t know how many, i just mean a big number) different fruits, as we do animals, and other things. And as far as history tells us, our kind has knowledge of the existence of animals and fruits for thousands of years…(following written history here, not gonna get into how old we think our kind is). Then of course, separating them into vegetables, fruits, nuts, etc only makes sense. But again, as this groups are not something that just exist, not a fundamental thing, but just words made up by men, we have to refine the definitions every so often to fit new discoveries, or make a new group all together. Take tomatoes for example. Is it a fruit or vegetable? If is difficult to describe tomatoes in a group of thousands, imagine to group Pluto in a small group. My point to all this is that the classification of Pluto as a planet or not from the “authorities” in the field, is probably due to pressure from the public to put them in a certain group, so they can print out their books a certain way, but professionals in the field just call it plain old Pluto, w/o classifying it. We are refering to a couple of bodies after all.
