Structure of the Galaxy.

Reading: Kaufmann, Chapter 25, Our Galaxy.

The evidence we have seen suggests that we are inside one of these. [This is the spiral galaxy M83 in blue light].

Here is a schematic picture of the parts of a spiral galaxy. Seen edge on.

Here is the same picture with names for the parts.

Motion in the Galaxy

Before going any further, it is important to understand that all of this is in motion. We first study motion and gravity.

Application to the Galaxy.

Davison E. Soper, Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA