Class 2, 1/13/03
In today's class we discussed the following.
* What? How? Why?
* Our universe is huge, dynamic, and massive.
*  We use metric system (SI) to put the above statement in perspective.
*  We showed what a liter is in the metric system.
* We showed  how to calculate ly in terms of  m.
* We discussed couple more points about two significant figures.
*  The above calculations were  intended to be helpful for students to do the Short-Answer questions in HW1.
*  To appreciate how huge is our universe, we listed the sizes of the following all in ly (light-year), unit, and
    ** Radius of the observable universe = (age of the universe) x (speed of light)
    ** Radius of our own galaxy, Milky Way.
    ** Radius of our star, the Sun.
    ** Radius of  our planet, the Earth'
    ** height of a person
* Chau drew them on what Chau calls "scientific scale" or "powers of ten scale" [rather than the (scary)  math name Log_10 scale].
* Speed and velocity are not the same.
* The current experimentally established number of dimensions of the universe is 3+1, 3 space dimensions plus 1 time, which we call the Minkowski spacetime (introduced by Minkowski, a professor of Einstein, after Einstein's special relativity paper of 1905, and a foundation on which Einstein developed his general relativity theory in 1917 -- our current understanding of spacetime barring the quantum effects.)  Although time is not absolute like in Newton's theory, it is distinct from space.

 Chau's comment:
I hope that such summary is helpful to you. Please let me know your opinion.

Of the discussions today, students are not asked to remember, nor to be tested on,  any of the numbers, except the speed of light and the age of the universe. However, students need to know how to answer Short-answer type of questions in HW1; and to draw scientific-scale plots for given numbers, as done in class today (and will be asked to do  in HW2 for the understanding of our universe being dynamic and huge).

This class web is intended to be helpful to students. The web links in my class web are meant to be informative. None of them will be tested. Our Quizzes and Final Exam will be limited to  lecture material, HWs, and reading assignments of the two textbooks.  Material in reading assignments not directly related to lectures and HW will constitute up to about 30% of Quizzes and the Final Exam.

 
******* Below was the Preview of the class ********
We will continue to discuss the first two topics:

· Powers of 10, Significant Figures, and Units.
· Our Place in the Universe

Please review lecture 1, and continue to read pages A-4 to A-12 and  pages 2 to 25 of  Cosmic Perspective, 3rd ed.

Sign-up sheet check/mark items
1. Check mark if you have carefully read the Syllabus.
2. Check mark if read all e-mails sent out after the previous class. (From now on class e-mails will be numbered as 10-B-e# in the subject.)
3. Put down the number of pages read of the assigned p.A-4 to A-12, Appendixes of TB1 (textbook 1).
4. Put down # of pages read of assigned p.2 to 25 of  Chapter 1 of TB1.
5. Initial.


If possible, please come to class a few minuets early to start the signing up.

You will notice that blank spaces of no initial or no marking are marked in blue. Once you catch up with what are asked for, you can fill in the blank with blue. If the blue is in error, please let Chau know at the end of the class. Please remember, these blues are mainly as reminders. No points will be taken off. Those who are consistent in attendance and doing assignments will be taken into consideration as participation for grade lifting.