The Field
Astronomy is the study of the regions beyond the Earth: planets, moons, stars, galaxies, and the universe itself. Astronomers study these objects not only by observing them with telescopes and other instruments, but also with mathematical and computer models. Astronomers therefore make heavy use of physics, mathematics, and computer science.
Equipment used ranges from radio telescopes half a mile across and high-speed computers to optical telescopes so big a truck could park on the mirror. The discipline ranges over many areas: radio astronomy; study of stars; their structure and evolution; origin of the universe and other astronomical systems; and the atmospheres and surfaces of planets.