Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 August 14 Giant Emission Nebula NGC 3603 in Infrared Credit: 2MASS Project, UMass, IPAC/Caltech, NSF, NASA Explanation: NGC 3603 is the largest region of glowing gas in our Milky Way galaxy. Spanning over 20 light years across, the giant emission nebula (HII region) is home to a massive star cluster, thick dust pillars, and a star about to explode. NGC 3603 was captured above in infrared light...