The Whirlpool Galaxy (designated NGC 5194 and M51) was imaged by the Hubble Space Telescope's (HST) Wide Field Planetary Camera 2 (WFPC2) in spring 2001. This image was released on 5th April. It is a composite of both visible light and hydrogen emission wavelengths (i.e. the red regions). The image illustrates the intricate structure of a galaxy's spiral arms and the associated dust, nebulae, and regions of star formation.
