Q:  What is the change in distance that light rays from
           Jupiter must travel to reach the Earth?
           That is, the difference between maximum and averge,
           or between average and minimum.  Express your answer in kilometers.


          The extra distance is just the radius of the Earth's orbit.
          Using a modern value, 

                                             11
                extra distance  =    1.5 x 10     m




   Q:  Assume that the amplitude of these variations in time
           is about eleven minutes.  Calculate the speed of light.


                                                        11
                                  distance      1.5 x 10    m               8
              speed of light  =  ---------  =   -------------   =   2.3 x 10   m/s
                                   time          11 * 60    s