A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.

What are the terrestrial planets?

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.

What are terrestrial planets simple definition?

Terrestrial planets are Earth-like planets made up of rocks or metals with a hard surface. Terrestrial planets also have a molten heavy-metal core, few moons and topological features such as valleys, volcanoes and craters.