What is Planet?
A planet is an extraterrestrial body orbiting a star or stellar remnant that is huge adequate to be rounded by its own gravity, not very big enough to cause thermonuclear fusion in its core, and has cleared its nearby region of planets.
After stars and stellar remnants, planets are some of the most massive objects identified to man. They play a vital part in the structure of planetary systems, and are as well considered, along with large moons, the most possible environment for life. Therefore planetary science is crucial not only to comprehend the structure of the universe, but as well to better know the development of life, and to aid the search for extraterrestrial intelligence. In addition, the planets visible from Earth have played a very important role in the shaping of human culture, religion and philosophy in abundant civilizations. Even at present, many people carry on to believe true the movement of the planets affects their lives, all though such causation is discarded by the scientific community.