Notes from Independent Study Meeting
                      Jan 31, 2022

Present: Richmond, Dayal

  - Dayal shows results of from last week

          a) no simple way to make axes on graph have same scale

          b) made table showing time taken to run, and fractional change
                in energy, as a function of timestep size

          c) results of running simulation for 200 years
                some timesteps conserve energy and don't take too long -- good

          d) results of "stupid sail" which falls straight into Sun
                discovered problems caused when two objects come too close


  - MWR provides notes on force on sail due to photon pressure

          a) see notes on webpage

          b) sail is assumed to be perfectly absorbing (not reflecting)

          c) sail is assumed to be face-on to Sun at all times


  - goals for next meeting (Thu, Feb 3): 
   
        1)  add section to code which 
                    a) computes photon force on sail
                    b) adds this to the gravitational force on sail

        2)  run a simulation in which sail starts at x=1.5E11 m, 
                    with zero velocity.

        3)  vary the mass and size of the sail, see how results vary