Spiral Arms
Regions of stars and interstellar matter that extend from the center of spiral galaxies, forming a spiral pattern; in the Milky Way, these include the Orion Arm where our Solar System resides.
Source: esa.int
APODs including "Spiral Arms"
Spiral Galaxy NGC 1350
06/10/2005
This gorgeous island universe lies about 85 million light-years distant in the southern constellation Fornax. Inhabited by young blue star clusters, the spiral arms of NGC 1350 seem to join in a circle around the galaxy's large, bright nucleus - giving the galaxy the appearance of a limpid cosmic eye. NGC 1350 is about 130,000 light-years across making it as large or slightly larger than our own Milky Way. For earth-based astronomers, NGC 1350 is seen on the outskirts of the Fornax cluster of galaxies, but its estimated distance suggests that it is not itself a cluster member. The sharp image also reveals many background galaxies, some visible right through NGC 1350.