PHY 111, Fall, 2005

Week 13
  Main Objectives

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
bulletwhat is meant by "standard candles" and the "distance pyramid" and why all steps in the pyramid are not equally accurate
bulletwhat RR Lyrae stars are and how they are used to find distances
bullethow synchrotron radiation is produced and what kinds of objects emit this type of radiation
bulletWhy we think there may be supermassive balck holes at the center of some galaxies
bulletwhat evidence we have that some galaxies may be colliding or exploding
bulletwhy stars are unlikely to collide when galaxies collide
bulletHubble's law and how it is related to the age of the universe
bulletwhat a quasar is and why they are important to our models of the history of the universe
bullethow we know quasars are small
bulletwhat Olber's paradox is and why it is important to our models of the history of the universe
bulletwhat the 3K background radiation is and why it is important to our of the history of the universe
bulletwhat evidence we have that galaxies are no longer being formed
bulletwhat the Big Bang model is and what evidence supports it

You should be able to compare and contrast :

bulletspiral, elliptical, and irregular galaxies
bulletSeyfert galaxies and normal galaxies
bulletactive galaxies and normal galaxies
Tuesday Go over exam.  Complete discussion of Milky Way and begin to talk about other galaxies.

Outside of class: Read Chapter 17. Go over Ch. 17 review questions.  Complete Calculations 1, 3, and 5 to be turned in on Thursday.
Thursday Continue discussion of other galaxies and cosmology (the study of how the universe has changed over time).

Outside of class: Read Chapter 18. Go over the Ch.18 review questions.