Class 3, 1/15/03,  Summary
* Discussed HW2
    ** Two typos corrected, thanks to Steve Tappel's quick response:
        *** Due date should be 1/22/04 , not 1/15/04 (Chau said that it would have violated causality.)
        *** The end of problem SA2.2. should be  "______ c." not  "______ ly."
    ** Attachment to HW2 is a scientific-scale (log_10) plot, which Chau drew on the blackboard in the previous class, showing that the universe is huge. Students are asked to make similar plots in problems, SA.2.3 & SA.2.4, showing that the universe is dynamic & massive, respectively.
    ** Such scientific-scale (log_10) plot is very useful. We will demonstarte how to use it to make relative-scale comparisons later on.
    ** Richter scale for earth quake is on a scientific scale (log_10 scale). Thus, an earth quake at one unit higher on Richter scale is ten time stronger.
    ** Chau also suggested that students go over HW2 first and use it as a guide where to pay more attention in reading.

* Started Week 2 material.
    ** Before going into the discussion of historical evolution of views of the universe, Chau emphasized the current understanding (supported by experimental evidence) of  how the universe operates. It operates according to two principles
            *** Democracy,
            *** Efficiency.
They will be repeated and elaborated as the course progresses. Therefore, there is no center in the universe (or, for that matter, every point can equally be qualified as " the center"). It is still all right for us to say, "Sun rises" and "Sun sets." For convenience of discussion, not only do we have the right to pick the most convenient "center", or reference frame, we ought to do so..
    ** Chau showed the animations available on the two web sites she linked for Class 3 on the class web. Due to lack of time, Chau did not get to show all the nice ones. Students are encouraged to look up the pictures and animations themselves, especially the following:
            *** The full picture of the Ptolemy model, in the first link, and the animation showing how epicycles (circular motion on circular motion) were used to explain (not successfully in the end) the varying planetary brightness and retrograde motions, in both links.
            *** A real cool one is the one in the second link showing "The main simplification of the Copernican model was that the retrograde loops of the planets as seen from the Earth occur naturally as a result of the Earth's motion combined with the motions of the planets."
            *** The coolest one is the animation showing the three laws of Kepler. They were later proven to be correct mathematically in Newton's Universal Laws of Gravity, which we will study in Week 3.
            *** We should know the important contributions of Ptolemy, Brahe, Copernicus, Kepler, Galileo, and Newton, as discussed in TB1 and in the second link, which lists their names.
           

* Chau announced that the two textbooks and a set of high school math books will be on 2-hr reserve at Shields, thanks to Ms. Karen Andrews' help.

* Ms. Karen Andrews gave a 25 min presentation, showing the class how to efficiently make of our library resources. Students applauded at the end. Indeed, we are most appreciative to Ms. Andrews for being able to do the presentation, especially out of her busy schedule.


Preview
We will start the following topics. After hand in HW1 on 1/22/04, student ought to start the reading assignments of Week-2 (1/15-1/22)
  · The Science of Astronomy; Read p.56-85, Chpt 3 of  TB1. 
  · A Universe of Matter and Energy; Read p.114-128, Chpt 4 of  TB1.
  · From starting page to p.xv and p.3-p.20 of Prefaces and Chpt 1 of TB2

Sign-up sheet check/mark items
1. Check mark if you have no questions about the Syllabus. (As always, send Chau an e-mail if you have any.)
2. Check mark if your have read all e-mails sent out after the previous class. (From now on class e-mails will be numbered as 010-B-e# in the subject.)
3. Check mark if you have finished reading the week-1 reading assignments, of Week-1 (1/8 - 1/15)
  · Powers of 10, Significant Figures, and Units;  Read p.A-4 to A-12, Appendix of TB1.
  · Our Place in the Universe; Read p.2-25, Chpt 1 of  TB1.
5. Initial.