A planet is a large celestial body that orbits a star, such as the Sun. Planets can be composed of rock, gas, or ice, and they vary widely in size and composition. In our Solar System, we have eight recognized planets, including Earth, Mars, and Jupiter. Each planet has unique characteristics and atmospheres that make them fascinating subjects of study. The classification of planets includes terrestrial planets, like Mercury and Venus, which are rocky, and gas giants, like Saturn and Neptune, which are primarily composed of gases. Understanding planets helps scientists learn more about the formation of our universe and the potential for life beyond Earth.