Explanation: Our solar system consists of the sun (the star), 8 planets, 63 moons, millions of smaller bodies like asteroids and comets and huge quantity of dust-grains and gases.

• Out of the eight planets, mercury, venus, earth and mars are called the inner planets as they lie between the sun and the belt of asteroids the other four planets are called the outer planets.
• Alternatively, the first four are called Terrestrial, meaning earth-like as they are made up of rock and metals, and have relatively high densities.

Source: NCERT – Fundamental of Physical Geography