Q:  Assuming that the pressure at the surface is zero,
             what is the pressure at the center of this star?

                               G * M * rho
               P(center)  =   ------------
                                   R


                              6.67 x 10^(-11) * 1.99 x 10^(30) * 1415 
                          =   ---------------------------------------
                                             6.95 x 10^8 


                          =   2.7 x 10^(14) N/m^2


               (This is about 100 times smaller than the actual pressure
                   at the center of the real Sun, which does NOT
                   have a constant density)


   Q:  How does that compare to the pressure of the air at the
             Earth's surface?


                P(Earth)   =   approx   1 x 10^(5) N/m^2


             So our very approximate estimate is about 10^(9) times
                 the pressure of the Earth's atmosphere
                 (and the TRUE central pressure is 10^(11) times
                  that of the Earth)