The Milky Way Galaxy

The galaxy in which we live is probably a typical spiral galaxy, although recent research shows it has a small bar across the center, making it a barred spiral. It is an island of tens of billions of stars together with gas and dust.

It is roughly the shape of a "flying saucer", with a bulge in the middle of a flat disc. Stars and dust are arranged into spirals within the disc, which measures about 100,000 light years across. Ancient globular star clusters form a halo around the Galaxy.

We live near a star (the Sun) roughly half way out along the disc. When we look at the night sky we can see a mass of distant stars in the disc, partly hidden by clouds of dust. These stars we call the Milky Way, and this is how our galaxy gets its name. It is sometimes just called the Galaxy.

The Milky Way is the second largest galaxy in the small cluster to which it belongs.

History of the Milky Way Galaxy

The galaxy has this appearance because of the Earth's position within the galactic plane around two thirds of the way out from the center, on the inner edge of the Orion Cygnus arm, with the majority of the galaxy being seen edge on. The concept of this faint band of light being made up of stars was proven in 1610 when Galileo Galilei used his telescope to resolve it into individual stars. In the 1920s observations by astronomer Edwin Hubble showed that the Milky Way was just one of around 200 billion galaxies in the observable universe.

Application of the Milky Way Galaxy

The Milky Way is the galaxy which is the home of our Solar System together with at least 200 billion other stars (more recent estimates have given numbers around 400 billion) and their planets, and thousands of clusters and nebulae, including at least almost all objects of Messier's catalog which are not galaxies on their own (one might consider two globular clusters as possible exceptions, as probably they are just being, or have recently been, incorporated or imported into our Galaxy from dwarf galaxies which are currently in close encounters with the Milky Way:


  1. Beiser, A. (1988). Physical Science (2nd Edition). New York, NY: McGraw Hill
  2. (Ref #2 - from internet)
  3. (Ref #3 - from book, library, journal)

This WikiPage developed by cody parks - 2011Fall