M51 whirls through space in this Hubble Space Telescope image. The galaxy, also known as the Whirlpool, is similar to our home galaxy, the Milky Way. The gravity of a small companion galaxy, at right, may have caused waves in the Whirlpool that created its spiral arms. Bright blobs within the spiral arms are stellar nurseries, giving birth to many new stars. [NASA/ESA]
Find out more in our radio program entitled Whirlpool Galaxy.