GENERAL KNOWLEDGE

Detailed explanation-1: -All are solid, dense, and rocky. None of the inner planets has rings. Compared to the outer planets, the inner planets are small. They have shorter orbits around the Sun and they spin more slowly.

Detailed explanation-2: -The planets Mercury, Venus, Earth, and Mars, are called terrestrial because they have a compact, rocky surface like Earth’s terra firma. The terrestrial planets are the four innermost planets in the solar system.

Detailed explanation-3: -The temperature of the early solar system explains why the inner planets are rocky and the outer ones are gaseous. As the gases coalesced to form a protosun, the temperature in the solar system rose. In the inner solar system temperatures were as high as 2000 K, while in the outer solar system it was as cool as 50 K.

Detailed explanation-4: -The four inner planets, or terrestrial planets, have solid, rocky surfaces. Earth, the third planet from the Sun, is the only planet with large amounts of liquid water, and the only planet known to support life. Earth has a large round moon. Mercury is the smallest planet and is the closest to the Sun.