Astronomy Picture of the Day

Explanation: This spectacular color picture of the core of barred spiral galaxy NGC 1512 (bottom panel) is a composite of the seven Hubble Space Telescope images arrayed along the top. Each top panel image was made with a filter and camera sensitive to a different wavelength band in the electromagnetic spectrum. Arranged by increasing wavelength, at the far left are two ultraviolet images from Hubble's Faint Object Camera. Next are two visible light images from its Wide Field Planetary Camera 2, followed on the right by three infrared images from the Near Infrared Camera and Multi-Object Spectrograph. To make a pleasing composite color image, blue tones were assigned to the invisible ultraviolet, greenish colors were used for the visible bands, and yellow/red for the invisible infrared band images. These images show that the center of NGC 1512 appears dramatically altered when viewed in different wavelength bands. In particular, the ultraviolet images highlight clusters of young, hot stars in a ring 2,400 light-years wide surrounding the core. What caused this cosmic starburst ring?