PHY 111, Fall, 2005

Week 12

 

  Main Objectives

You should be able to explain what Cepheid variable stars are and how they are used to find distances.

You should know what is meant the following terms and know how they are related to one another:  proper motion, radial velocity, and tangential velocity.

You should be able to compare and contrast open and globular clusters.

You should be able to discuss:

bulletthe main parts of our galaxy (galactic disk, galactic plane, nucleus, nuclear bulge, and halo)
bulletthe rotation rates of stars in different parts of the galaxy and what we learn from this
bulletthe basis on which we divide stars into two populations

You should be able to explain:

bulletwhat the missing mass problem is and what possible solutions there are
bullethow we determine the mass of a galaxy
bulletWhy we can see further into the galaxy using radio wavelengths than using visible light
bulletwhy we see the same number of stars when looking toward the galactic center as when looking away from it
bulletwhat the 21 cm line is and why it is important
Tuesday Review stellar evolution in small groups.  Begin discussion of galaxies by talking about our own galaxy, The Milky Way.

Outside of class: Finish your preparation for the exam.

Thursday Exam III on Chapters 11-15.

Outside of class: Read Chapter 16 and Ch. 15 Section 9. Go over the Chapter 16 review questions.  Complete the Activity at the end of Chapter 16 to be turned in next Tuesday.