IRAS Image of the Andromeda Galaxy

This computer-processed image of the Andromeda galaxy (M31) identified regions where young stars are probably forming, seen here as yellow and white areas. The image was processed from observations of the galaxy by the Infrared Astronomical Satellite (IRAS). The colors represent the intensity of infrared radiation observed by the IRAS telescope. Blue areas represent regions of faint infrared emission, while green, yellow, orange and red areas show respectively more intense infrared emissions. Brighter areas represent regions populated by either numerous or massive young stars. Like our Galaxy, the Milky Way, Andromeda is a spiral galaxy. Andromeda is approximately 20,000 light-years across, about 2 million light-years away. (One light-year is about 6 trillion miles.) It is the nearest spiral galaxy similar to the Milky Way. IRAS observations of the galaxy represent the first extensive, high-sensitivity study of Andromeda in the infrared.