Planets are sizable celestial bodies that orbit a star, such as the Sun, and are distinguished by their ability to clear their orbital paths of debris. They do not emit light of their own but reflect the light from their parent star. Planets are classified into categories like terrestrial planets, which have rocky surfaces (e.g., Earth and Mars), and gas giants, which are primarily composed of hydrogen and helium (e.g., Jupiter and Saturn). Additionally, some planets have natural satellites, or moons, orbiting them. The study of planets encompasses their formation, composition, atmospheres, and potential for hosting life, contributing significantly to our understanding of the solar system and beyond.