Electromagnetic+Spectrum

=== Scientists break up the sun’s light into a spectrum by using a device called a spectrograph. Dark lines form in the spectra of stars when gases in the stars’ outer layers absorb specific wavelengths of the light that passes through the layers. T he temperature of these outer layers determines which gases produce visible spectral lines. By studying the spectrum of a star, scientists can determine the amounts of elements that are present in a star’s atmosphere. When light passes through hydrogen gas and then through a slit in a prism, dark lines appear in the spectrum. Hydrogen and lines from other elements in the solar spectrum are shown in the bottom spectrograph. ===