En la edad media seis eran considerados planetas empezando por mercurio.
Hay nueve planetas solares Esta vision es de 1930- 2006
Desde 2006 la definicion de planeta es la siguiente A celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
European Renaissance Renaissance planets, ca. 1543 to 1610 and ca. 1680 to 1781 1 Mercury ☿ 2 Venus ♀ 3 Earth ⊕ 4 Mars ♂ 5 Jupiter ♃ 6 Saturn ♄ See also: Heliocentrism
With the advent of the Scientific Revolution, use of the term “planet” changed from something that moved across the sky (in relation to the star field); to a body that orbited Earth (or that were believed to do so at the time); and by the 18th century to something that directly orbited the Sun when the heliocentric model of Copernicus, Galileo and Kepler gained sway.
Thus, Earth became included in the list of planets, whereas the Sun and Moon were excluded. At first, when the first satellites of Jupiter and Saturn were discovered in the 17th century, the terms “planet” and “satellite” were used interchangeably – although the latter would gradually become more prevalent in the following century. Until the mid-19th century, the number of “planets” rose rapidly because any newly discovered object directly orbiting the Sun was listed as a planet by the scientific community.