ASTRONOMY 101
Spring 2001
Exam 2 Study Guide

Note: The Exam will be similar in style to the first exam, but shorter. The Exam will be closed book and closed notes. You may bring a calculator to use, although I don't expect you to need it. The emphasis will be on the topics and material we cover and discuss in class and homeworks, including related readings that fill in details or build on our classwork. I will not be searching through readings for trivia on which to base questions; rather, I will be focusing on important concepts and logical thinking. Nevertheless, some numbers are important, especially when they provide important comparisons or critical evidence concerning present or past phenomena in the solar system.  Also, while the homework questions and topics are important, they are by no means a comprehensive guide to important topics.

The Exam will cover material through the lectures of February 26.

The following topics/leading questions are meant as a guide but are not guaranteed to be a comprehensive listing of all relevant and important topics covered thus far.

I. Meteorites

   1. general types
   2. chondritic abundances, chondrules
   3 .Allende meteorite (what type? why important? what do we know about it?)
   4. Murchison meteorite  (what type? why important? what do we know about it?)
   5. Aluminum-26
   6. why did it take until the 19th century before anyone believed that meteorites could exist?
       what does this illustrate about the workings of science?

II. Demise of the Dinosaurs (K/T Extinction)

   1. what is K/T boundary layer?
   2. what is found in K/T boundary layer?
   3. why is this suggestive of an impact?
   4. other evidence?
   5. connection of impact to extinctions?

III. Discovery of Uranus, Neptune, Pluto as well as Ceres and other asteroids

   1. discovered when? by whom? under what circumstances?
       discovered deliberately or accidentally?
   2. significance of each discovery?
   3. features of the asteroid belt
   4. the Titius-Bode rule: what is/was it? what did it predict?
       what does it illustrate about the process of science?
       why is it not worth calling a "law"?

IV. Is Pluto a Planet?

   1. discovery of Pluto (same as above)
   2. does Pluto meet our criteria for "planethood"?
   3. discovery of Pluto's moon Charon - significance?
   4. discovery of Chiron (TNOs) - stability, lifetime of TNOs
   5. prediction of existence of Kuiper Belt - why?
       discovery of Kuiper Belt: when, why, by whom?
   6. signficance of Kuiper Belt
   7. comets
   8. what was unusual about Comet Shoemaker-Levy IX?
   8. history of Halley and Halley's comet
   9. Oort Comet cloud; relationship to Kuiper Belt
 10. how do we know there is an Oort cloud?
 11. how do estimate lifetimes of comets?
 12. what conclusions can we draw about comets, about the Oort cloud, from estimating the life of a single comet?
 

V.  Asteroids & Armageddon

   1. what are asteroids? types?
   2. where do they come from?
   3. Apollos, Atens, Amors: what are they, who cares?
   4. Kirkwood Gaps, structure of asteroid belt
   5.  likelihood of collisions with Earth of asteroids of different sizes
   6.  Tunguska Event
   7.   relative danger of asteroid impacts (What me worry?)