SPECTRAL SIGNATURE
Spectral signature is the difference in reflectance and emittance of light waves. You determine spectral signature by breaking apart light waves into their separate colors. The spectral signature of stars indicates the composition of the stellar atmosphere. The spectral signature of hydrogen is 650, making it very easy to determine the Red Shift of stars. The emission spectrum has spikes because it is the amount of photons being released by the atom at that wavelength, absorption lines are where light has been absorbed by the atoms, creating dips in the spectrum.