http://www.top-directory.net/science/space/planets/Best collection of website in the Internet. Best general, niche and regional Website - You can find all this here. </p><p>The International Astronomical union or IAU officially defines planets as celestial bodies. It is star or stellar body. The body is large enough and has it own atmosphere and gravity. The body moves along a particular orbit. But planets are not that massive that it can cause its own thermonuclear fusions in its core and have clear planetary space. </p><p> The term planet is derived from bits of everything. Everything from history, religion, myth and science are related to the origin of the term planet. It is a matter of fact that planetary movements are still now related in various religions and astrology. But no very concrete result of scientific reasoning or knowledge is there to push the fact. The international community of scientists often discards these facts. There are in total 8 planets identified by the international astronomical union. Which is mercury, Venus, earth, mars, Jupiter, Saturn, Uranus, Neptune. These are a big planet that moons orbiting them and follow a fixed orbit for revolution around the sun. The other dwarf planets include Pluto, Ceres and Eris. These planets too have the same property. </p><p> There are two major divisions of planet which includes low density gas giants and much more smaller terrestrials. </p><p>