This cool space wallpaper shows a composite view of the giant elliptical galaxy NGC 1399. The stellar component, as observed at optical wavelengths, is shown in white at the center of the image. The galaxy is embedded in a hot atmosphere of ionized hydrogen gas, which is shown in blue. With temperatures up to tens of millions of K, the hot gas shines brightly in X-rays and was observed using NASA's Chandra X-ray Observatory.
Credit: Digitised Sky Survey/NASA Chandra/Very Large Array (Robert Dunn et al. 2010)