8.962  General Relativity

Dear 8.962 Students,

     I discovered at my office hour today that the wording of Problem 2(c) on Problem Set 4 might not have been as clear as it should be.  In this problem you are first asked to calculate the proper time measured by the clock C along the prescribed trajectory in the full Schwarzschild metric.  I think that part should be clear, but I want to try to clarify the next part of the question.  In this part you are asked to calculate the difference, let's call it Delta, between the answer you found for the prescribed trajectory and the sum of the answers you found in parts (a) and (b).  That is, Delta = Ans(c) - Ans(a) - Ans(b).  When I said "to lowest order in the small quantities indicated in parts (a) and (b)," what I meant was for you to calculate Delta to lowest nonvanishing order in the two small quantities.

     The problem was that some students interpreted "lowest order" to mean first order in each of the small quantities, and those students then found Delta = 0.  But you should not stop there, but continue the expansion until you find the first nonvanishing contribution.

     Best wishes,

                             -- Alan --

Dear 8.962 Students,
        Due to the snowed out lecture, recitation class, and office hour today, we will postpone the
due date of Problem Set 1.  Instead of being due on Wednesday at 5:00 pm, it will be due on Thursday
at 5:00 pm.  I think that this will allow most of you to finish the problem set.  If it is not
enough time, we will be generous with extensions until Friday at 5:00 pm.  By that, I mean that if
you ask for an extension, the answer will be yes --- no suspense.  If you need an extension, please
send an email to Andrew Turner and me to let us know.
        Best wishes,
                             -- Alan --

Dear 8.962 Students,

     Our Stellar website is now up and running at http://stellar.mit.edu/S/course/8/sp17/8.962/.  Problem Set 1 is posted to the website.

     In addition, Andrew Turner has typed up lecture notes in LaTeX, and intends to do that for every lecture.  The notes for Lecture 1 are posted. Super thanks to Andrew --- I am sure that all of us will find these notes very useful.

          Best wishes,
                Alan
=================================================================
 Department of Physics            Center for Theoretical Physics
 V.F. Weisskopf Professor of Physics and MacVicar Faculty Fellow
  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
  Alan H. Guth                                                  
  Center for Theoretical Physics            guth@ctp.mit.edu    
  Massachusetts Institute of Technology     Phone: 617-253-6265 
  77 Massachusetts Avenue, Room 6-322       Fax:   617-253-8674 
  Cambridge, Massachusetts 02139-4307                           
=================================================================