rth , in solar system is ONE of the eight PLANETS , one press away from the sun from NEAR and far in order for the third row , is the diameter of the solar system, the largest mass and density of Earth-like planets, the sun 150 million kilometers away. Earth's rotation is from west to east, while around the sun revolves . Earth is 4 billion to 4.6 billion years old. It has a natural satellite -the moon , and the two form a celestial system-the Earth-Moon system . It originated in the primitive solar NEBULA 4.6 billion years ago .The earth's equatorial radius is 6378.137 kilometers, polar radius is 6536.752 kilometers, the average radius is about 6371 kilometers, and the equatorial circumference is about 40076 kilometers. It has an irregular elliptical sphere with slightly flat equatorial and slightly polarized poles. The surface area of the earth is 510 million square kilometers, of which 71% is OCEAN and 29% is land. The earth looks blue in space .There are core, mantle and crust structures inside the earth, and hydrosphere, atmosphere and magnetic field outside the earth. The earth is the only celestial body in the universe known to have life, and is home to millions of living things including humans.