We are known about Planets. Earth Planet is collection of peoples. All over world are known about planet. We are known to planet. Total nine planets in the universe. According to the definition, there are currently eight planets and four dwarf planets known in the solar system. The definition distinguishes planets design from smaller bodies, and is not used outside the solar system, where smaller bodies cannot be found yet. Exoplanets are covered separately under a complementary 2003 draft guideline for the definition of planets, which distinguishes them from dwarf stars, which are larger. In its long life, the word has meant many different things, often simultaneously. Over the millennium, use of the term was never strict and its meaning has twisted and blurred to include or exclude a variety of different objects, from the Sun and the Moon to satellites and asteroids. As knowledge of the universe grew, the word “planet” grew and changed with it, casting off old meanings and adopting new ones, though never arriving at a single, concrete definition.

By the end of the 19th century, the word “planet” had, without being defined, settled into a comfortable working term. It only applied to objects in the Solar System; a number small enough that any differences could be dealt with on an individual basis. After 1992 however, astronomers began to discover many additional objects beyond the orbit of Neptune, as well as hundreds of objects orbiting other stars.