;Quantity                        Value                  Unit
atomic_mass_constant    =       1.660538782d-27      ;       kg
boltzmann               =       1.3806504d-23        ;       J K^-1
boltzmann_eV_K          =       8.617343d-05         ;       eV K^-1
electron_mass           =       9.10938215d-31       ;       kg
electron_volt           =       1.602176487d-19      ;       J
radiation_constant      =       3.74177118d-16       ;       W m^2
neutron_mass            =       1.674927211d-27      ;       kg
big_g                   =       6.67428d-11          ;       m^3 kg^-1 s^-2
planck                  =       6.62606896d-34       ;       J s
proton_mass             =       1.672621637d-27      ;       kg
speed_light             =       2.99792458d+8        ;       m s^-1
sigma		        =       5.6704d-08           ;       W m^-2 K^-4 Stefan-Boltzmann
wiens_m_K               =       2.8977685d-03        ;       m K
;pi			=	3.1415926536
;use IDL read-only system variable for pi in double precision; that is, !dpi