Photograph by G. Fritz Benedict, Andrew Howell, Inger Jorgensen, David Chapell (University of Texas), Jeffery Kenney (Yale University), and Beverly J. Smith (CASA, University of Colorado), and NASA
A merry-go-round of young stars flashes around the center of galaxy NGC 4314. This spectacular close-up from the Hubble Space Telescope reveals the basic structural elements of a galaxy. At the center glows a dense cluster of old stars, their mature status indicated by temperatures in the yellow and white part of the spectrum. Even deeper into the center probably lurks an invisible black hole, common to most galaxies. A black hole is matter so densely compacted that even light can't escape.
New stars usually appear in the spiral arms of a galaxy. But in this case the young, ultra-hot stars (blue and purple) have formed in a ring, created when clouds of gas collapse into superdense cores. Ten times hotter and one million times brighter than our sun, these new stars will eventually cool down and resemble the older stars near the center. Clouds of dust and gas fog the edges of the image. Even farther out lies the unseen weave of dark matter, whose gravitational force keeps the galaxy's hundreds of billions of stars bound together.