What is extinction of light? The term “extinction” means the loss of light in the atmosphere from a directly transmitted beam. Two different mechanisms contribute to extinction: absorption and scattering.
What causes interstellar extinction? Interstellar extinction is the dimming of light from stars and other distant objects, especially pronounced in the galactic plane, due the combined effects of interstellar absorption and scattering of light by dust particles.
What is the extinction curve? The extinction curve, which represents the wavelength dependence of dust extinction, is used to relate the intrinsic stellar SED to the observed SED affected by dust extinction. Thus, the extinction curve is the fundamental tool for interpreting the observational SEDs of galaxies.
What is the difference between interstellar extinction and interstellar reddening? The extinction due to dust is not equally effective at all wavelengths. The shorter the wavelength, the higher the extinction — blue light is affected more strongly than red light. Therefore, stars behind a lot of dust look redder than they really are. This is called interstellar reddening.