They use telescopes to study planets, stars, and other objects in space
Humans have long gazed toward the heavens, searching to put meaning and order to the universe around them. Although the movement of constellations — patterns imprinted on the night sky — were the easiest to track, other celestial events such as eclipses and the motion of planets were also charted and predicted.
Definition of astronomy: Astronomy is the study of the sun, moon, stars, planets, comets, gas, galaxies, gas, dust and other non-Earthly bodies and phenomena. In curriculum for K-4 students, NASA defines astronomy as simple "the study of stars, planets and space." Astronomy and astrology were historically associated, but astrology is not a science and is no longer recognized as having anything to do with astronomy. Below we discuss the history of astronomy and related fields of study, including cosmology.
Historically, astronomy has focused on observations of heavenly bodies. It is a close cousin to astrophysics. Succinctly put, astrophysics involves the study of the physics of astronomy and concentrates on the behavior, properties and motion of objects out there. However, modern astronomy includes many elements of the motions and characteristics of these bodies, and the two terms are often used interchangeably today.
Unlike most other fields of science, astronomers are unable to observe a system entirely from birth to death; the lifetime of worlds, stars, and galaxies span millions to billions of years. Instead, astronomers must rely on snapshots of bodies in various stages of evolution to determine how they formed, evolved and died. Thus, theoretical and observational astronomy tend to blend together, as theoretical scientists use the information actually collected to create simulations, while the observations serve to confirm the models — or to indicate the need for tweaking them.
Astronomy is broken down into a number of subfields, allowing scientists to specialize in particular objects and phenomena.