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
06/07/2013

The universe is filled with galaxies. But to see them astronomers must look out beyond the stars of our own galaxy, the Milky Way. This colorful Hubble Space Telescopic portrait features spiral galaxy NGC 6384, about 80 million light-years away in the direction of the constellation Ophiuchus. At that distance, NGC 6384 spans an estimated 150,000 light-years, while the Hubble close-up of the galaxy's central region is about 70,000 light-years wide. The sharp image shows details in the distant galaxy's blue star clusters and dust lanes along magnificent spiral arms, and a bright core dominated by yellowish starlight. Still, the individual stars seen in the picture are all in the relatively close foreground, well within our own galaxy. The brighter Milky Way stars show noticeable crosses, or diffraction spikes, caused by the telescope itself.