Emission Line

An emission line is a bright feature seen in a spectrum of light emitted by a celestial object, like a star or galaxy. It occurs when atoms or molecules in a hot, energized gas release specific wavelengths of light as their electrons jump down to lower energy levels. These specific wavelengths produce distinct lines, acting like a fingerprint that reveals the composition, temperature, and physical conditions of the emitting object. Emission lines help astronomers analyze and understand the materials and processes occurring in space.