The inner planets are also called _____ planets due to their composition.

The inner planets of our solar system – Mercury, Venus, Earth, and Mars – are referred to as terrestrial planets. This designation comes from their solid, rocky surfaces, which contrasts with the gas giants found in the outer solar system. Terrestrial planets are characterized by their composition primarily of silicate rocks and metals, making them denser than the outer planets, which are composed predominantly of gases like hydrogen and helium. The term "terrestrial" derives from the Latin word "terra," meaning Earth, highlighting the rocky nature of these planets and their similarities to our own planet. This understanding of planetary composition is fundamental when studying the characteristics and features of the solar system.