NASA's Hubble Space Telescope has taken this image of the galaxy NGC 1073, a "barred spiral" galaxy much like our own Milky Way. According to the European Space Agency, which works with NASA on the Hubble project, more than two-thirds of the spiral galaxies in the universe have the bar-like structure seen above at their centers, but in the early universe, only about one-fifth of such galaxies had them. Some scientists have posited that the development of the bar signals a galaxy's passage from the adolescent star-formation stage into maturity. The bars are thought to be the product of gravitational density waves that pull gases in toward the galaxy's center. In the image, three objects that appear to be stars are not stars at all but quasars, the brightest objects in the universe, caused by matter being drawn into black holes billions of light years away. A version of the image with these quasars labeled can be found here.
Below, recent Pictures of the Day:
This article available online at: