This collage of galaxies from NASA's Wide-Field Infrared Survey Explorer, or WISE, showcases the many "flavors" that galaxies come in, from star-studded spirals to bulging ellipticals to those paired with other companion galaxies. The WISE team put this collage together to celebrate the anniversary of the mission's launch on Dec. 14, 2009.
After launch and a one-month checkout period, WISE began mapping the sky in infrared light. By July of this year, the entire sky had been surveyed, detecting hundreds of millions of objects, including the galaxies pictured here. In October of this year, after scanning the sky about one-and–a-half times, the spacecraft ran out of its frozen coolant, as planned. With its two shortest-wavelength infrared detectors still operational, the mission continues to survey the sky, focusing primarily on asteroids and comets.
NGC 300 is seen in the image in the upper left panel. This is a textbook spiral galaxy. In fact, it is such a good representation of a spiral galaxy that astronomers have studied it in great detail to learn about the structure of all spirals in general. Infrared images like this one from WISE show astronomers where areas of gas and warm dust are concentrated -- features that cannot be seen in visible light. At about 39,000 light-years across, NGC 300 is only about 40 percent the size of the Milky Way galaxy.