The Milky Way - Spiral Structure
The Milky Way is a Barred Spiral galaxy approximately 100,000 light years in
diameter. It is the second largest member of the Local Group of galaxies, and
possesses several satellite galaxies, including SagDEG, the Large Magellanic Cloud,
the Small Magellanic Cloud, and more than 200 globular clusters.
There are between 200 billion and 400 billion stars in the Milky Way, with a total
mass between 750 billion and 1 trillion solar masses. The Sol System is located
approximately 28,000 light years from the galactic core, in a small spiral arm known
as Orion. The Orion Arm, though minor, is one of several spiral bands that wrap
around the galaxy.