Astronomy is the study of all events outside a planet's atmosphere.
- A person who studies this field is known as an astronomer.
This field of science uses mathematics, physics, and chemistry in order to explain the origin and evolution of any and all objects outside of a planet's atmosphere. Related, cosmology is a branch of astronomy that studies the universe as a whole.
Professional astronomy is generally split into observational and theoretical branches.
- Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics.
- Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena.
Astronomy is one of the few sciences in which amateurs can play an active role. Amateur astronomers have helped with many important discoveries, such as finding new comets.