Astrophysics is a science that applies principles of physics to many fields of astronomy. Astrophysicists try to determine the physical nature, origin, and development of the solar system, galaxies, and the universe. Almost all astronomers are also astrophysicists.
Astrophysicists use telescopes in many studies. Optical telescopes enable them to view celestial objects that give off electromagnetic waves in the form of visible light. They use other kinds of telescopes to study the other forms of electromagnetic radiation—radio waves, infrared rays, ultraviolet rays, X rays, and gamma rays. One of their major techniques is the study of patterns of wavelength (distance between successive wave crests) of the radiation emitted by celestial objects. For example, analysis of the pattern of wavelengths in the light from a star provides information about the star’s density and temperature.
See also Astronomy; Cosmology; Spectrometer; Telescope (Radio and microwave telescopes).
