What is Spectroscopy Spectroscopy is a very important tool in astronomy. It is detailed study of the light from an object. Light is energy that moves through space and can be thought of as either waves or particles. The distances between the peaks of the waves of light are called the light's wavelength.
Light is made up of many different wavelengths.
Spectrometers are instruments which spread light out into its wavelengths creating a spectra. Within this spectra, astronomers can study emission and absorption lines which are the fingerprints of atoms and molecules. An emission line occurs when an electron drops down to a lower orbit around the nucleus of an atom and looses energy. An absorption line occurs when electrons move to a higher orbit by absorbing energy. Each atom has a unique spacing of orbits and can emit or absorb only certain energies or wavelengths.