Are you ready to meet the planets in the solar system, which is the star system that includes Earth? If yes, let's first understand what the planet is! Although the definition of the concept of "planet" has been controversial since Pluto, the necessary conditions for us to call a planet a "planet" are as follows: To be in the orbit of the Sun, to have enough mass to turn its shape into a sphere by gravity, and to be the dominant planet in its region. . Once we have learned this, we can begin to examine the planets in the solar system and their structural properties more closely.