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"
M100: A Grand Design
01/06/1997
Majestic on a truly cosmic scale, M100 is appropriately known as a Grand Design spiral galaxy. A large galaxy of over 100 billion or so stars with well defined spiral arms, it is similar to our own Milky Way. One of the brightest members of the Virgo Cluster of galaxies , M100 (alias NGC 4321) is 56 million light-years distant in the spring constellation of Coma Berenices. This Hubble Space Telescope image of the central region M100 revealing bright stars and intricate winding dust lanes was made in 1993 with the Wide Field and Planetary Camera 2. Studies of stars in M100 have recently played an important role in determining the size and age of the Universe.