Out of a sea of silver sparkles from nearby stars, a ripple of bright blue gas threads through this galaxy like a misshapen lake. A keen eye can also spot a few other galaxies that, while masquerading as stars at first glance, reveal their true nature on closer inspection of this image from the Hubble Space Telescope (NASAHubble). The central galaxy streaked with color was discovered by DeLisle Stewart in 1900 and is located approximately 28 million light-years away. It contains an active galactic nucleus: an extremely luminous central region so alight with radiation that it can outshine the rest of the galaxy put together. This galaxy has been imaged by Hubble for several studies of nearby active galaxies. By using Hubble to explore the small-scale structures of active galaxies in nearby galaxies, astronomers can observe the traces of collisions and mergers, central galactic bars, nuclear starbursts, jets or outflows, and other interactions between a galactic nucleus and its surround...