Astronomy 20 Take Home Test


Rules:  The honor system applies, so please act honorably.  You may NOT work with others, whether they are in the class or not.  The ONLY exceptions to this rule are the El Camino College astronomy tutor and you may consult me for help.  All published, written materials are available to you.  Written correspondence is not, of course.  You should find chapter 15 in your text to be most useful. 


Answers are to be typed.  Sketches encouraged to be freehand.  Please proof read your exam prior to turning it in.  You will be marked down for poor writing or sloppy work.   Answers are to be IN YOUR OWN WORDS.




Q1.  Illustrate and describe, in general terms how the solar system formed.  Show the formation taking place in several phases.  These phases should include at least the initial gaseous and accretion phase, the planetismal phase, and as planet formation finishes up.  Be sure to describe how the temperature varies in the accretion disk.  Also describe the role that collisions play, especially in the final stages of planet formation within the accretion disk.  This may take one or more pages to illustrate and describe properly.  20 points.


Q2.  Using your answer to Q1, describe why all of the planets orbit in the same direction and almost all of them rotate in the same direction.  10 points.


Q3.  Using your answer to Q1, describe why Mercury is mostly iron and the trend is for lower density for planets farther from the Sun.  10 points.


Q4.  Describe the role that ice plays early in the formation of the gas giants.  Why are all of the gas giants located in the outer solar system?   How did this enable them to become so large?  5 points.


Q5.  What are comets made of?  What do they have to do with the formation of the solar system?  What is the Kuiper Belt?  What is the Oort Cloud?  Where are they located?  5 points.


Bonus:  Exceptions to rules are listed below.  Pick your five favorite ones and describe why each is an exception, and how such an exception could come about.  1 point each (5 points max).  Note: only the first five that you turn in will be graded.


  1. Rotation of Venus
  2. Density of Earth
  3. Size and density of the Moon
  4. Lack of nitrogen on Mars
  5. The existence of the asteroid belt
  6. The four large Galilean Satellites
  7. The beautiful rings of Saturn
  8. Tilt of Uranus
  9. The patchwork surface of Miranda
  10. Orbit of Triton
  11. Pluto and Charon