This image released by NASA 28 September, 2006, shows the Andromeda galaxy in a new composite image from NASA's Galaxy Evolution Explorer and the Spitzer Space Telescope. The Explorer detected young, hot, high-mass stars, which are represented in blue, while populations of relatively older stars are shown as green dots. The bright yellow spot at the galaxy's center depicts a particularly dense population of old stars. Swaths of red in the galaxy's disk indicate areas where Spitzer found cool, dusty regions where stars are forming. These stars are still shrouded by the cosmic clouds of dust and gas that collapsed to form them. Together, Explorer and Spitzer complete the picture of Andromeda's swirling spiral arms. Hints of pinkish purple depict regions where the galaxy's populations of hot, high-mass stars and cooler, dust-enshrouded stars co-exist. Located 2.5 million light-years away, Andromeda is our largest nearby galactic neighbor. The galaxy's entire disk spans about 260,000 light-years. The Milky Way galaxy's disk is about 100,000 light-years across. AFP PHOTO/NASA =GETTY OUT=....(Photo credit should read -/AFP/Getty Images)