The study of planets and celestial bodies is known as "astronomy." Astronomy is a natural science that focuses on the observation and understanding of celestial phenomena, including stars, planets, comets, and galaxies. This field encompasses various sub-disciplines, such as astrophysics, which looks at the physical properties of celestial objects, and planetary science, which is specifically concerned with the study of planets and their moons. Astronomers use telescopes and other instruments to gather data and make discoveries, helping us understand the universe's formation, structure, and potential for life beyond Earth.