A false-color far-infrared composite image of the Andromeda Galaxy, the nearest spiral galaxy to the Milky Way. The image consists of 11,000 separate exposures taken by the Spitzer Space Telescope's Multiband Imaging Photometer at 24 micrometres. The image is dominated by emission from hot cosmic dust; this is the sharpest image ever taken of this component of the interstellar medium in another galaxy. This is in dramatic contrast to the more-familiar view at visible wavelengths, which is dominated by starlight.Image credit: NASA/JPL-Caltech/K. Gordon (University of Arizona)