'Tis strange you know? I think the original classification scheme proposed by the IAU committee is practically flawless and rigorously scientific. Yet the bunch of hard headed astronomers that are about still want to give in to history and culture and be defiant, since the scheme does not fit their fantasies. Read this . They are arguing over whether to call pluto sized objects "plutons" or "dwarf planets." It just shows the silliness that can rule scientific discussion and debate at times. Look at this: They want to insert the criterion that a plant must be: ''...by far the largest body in its population of bodies..." By far? Come on, where's the science in that??? Please Register or Log in to view the hidden image! If they just stick with the original IAU proposition all will be well.
Any classification of planets is cultural. It is really ridiculous to even care. It is the phenomena, not the names, which matter here.
If balls of gas can be considered planets then just about anything can be. I am thoroughly disappointed in our solar system now. To me there are only four planets: Mercury, Mars, Venus and Earth. The rest are just colored air.
The definition is a bit ambiguous, cause in fact no planet is perfectly "round". Earth is not round, and if you look pictures of Vesta: Please Register or Log in to view the hidden image! some might say it is "roundish", so where we put the limit? In fact, Sedna also seems round: Please Register or Log in to view the hidden image! and is not considered a planet? and with the plethora of bodies similar to Xena awaiting to be discovered in the Kuiper Belt and beyond, the list can grow spectacularly
Being round isn't sufficient. A marble orbiting the Sun obviously wouldn't be a planet, for example. The object must be massive enough that it can't not be round. The Kuiper belt object collage is only indicating relative size. It's not supposed to show precise shape or surface detail. Sedna, Vesta, and others may yet be included in the list of new planets under the drafft definition. We may suddenly find ourselves in a system of 50-odd planets - and that's only classifying the objects already known!
What if you have 3 stars in a solar system, and two of them orbits a bigger one. would those two be planets then? remember, there are also four elements: fire, earth, water and air (corresponding modern words: plasma, solid, liquid and gas) lol, you can't draw a line anywhere because there IS no line!
Well, they know that. I think they really mean if it is shaped by self gravitation, which tends towards spherical shapes. The number of planets, I think, would be the least important. There a trillions of stars, many of which might harbour planets. We know of 180+ extra planets so far...
Dam ceres has more then a 100 times less mass then the Jupiters moon Ganymedes, I can't see this definition last long
I think the term 'Potatoe' shape body classification for planets and asteroids would be closer to the truth, don't you think? Please Register or Log in to view the hidden image!
Mine is a more practical definition of Planet. Planet: A Celestial body worth conquering and ruling over. Every other non-stellar object is just cosmic flotsam. Bow down, or be teleported to a world/object unworthy of being conquered/ruled over.
