A planetarium is a theater built primarily for presenting educational and entertaining shows about astronomy and the night sky. It features a domed ceiling that displays stars, planets, and other celestial objects, often using advanced projection technology. Visitors can learn about constellations, the solar system, and various astronomical phenomena in an immersive environment. Many planetariums also offer interactive exhibits and programs for all ages, making them popular destinations for schools and families. They may host special events, such as guest lectures or themed shows, to engage the public in topics related to astronomy and space exploration.