Electromagnetic Spectrum: The full range of electromagnetic radiation, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays, each with unique properties and applications in astronomy.
Spectroscopy:The study of the absorption and emission of light by matter, which can provide information about the chemical composition, temperature, and other properties of celestial objects.
Atmospheric Absorption: The process by which the Earth's atmosphere absorbs certain wavelengths of electromagnetic radiation, including a significant portion of ultraviolet light, requiring the use of specialized telescopes to observe these wavelengths.