AST 307 · Introductory Astronomy
Fall 2003


Chapter 24, 25  Nov. 17-21

  1. Describe the various types of galaxies, in particular comparing spiral, elliptical, and irregular galaxies.

  2. Describe two of the variations on the standard candle method which are used to measure distances to distant galaxies.

  3. Describe how astronomers measure the distribution of mass within galaxies, and describe the typical results for spiral galaxies.
    How do these measurements indicate that there is unseen, or dark, matter in galaxies?

  4. Describe the evidence that galaxies collide or interact with each other, and the effects of these interactions. Stars almost never collide with each other. Why are collisions much more common for galaxies?

  5. State Hubble's law. Say how Hubble's constant is measured. Why doesn't Hubble's law apply to objects in the solar system or in the Milky Way?

  6. Describe two types of active galaxies and say how they differ from normal galaxies like the Milky Way.

  7. Describe a theory about how active galaxies could have formed. What makes us think that active galaxies have supermassive black holes in their nuclei?

14 November 2003
Astronomy Program · The University of Texas at Austin · Austin, Texas 78712
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