physconst.h
/*
* Collection of physical constants.
*/
/* bolzman constant in cgs */
#define KBOLTZ 1.38e-16
/* mass of hydrogen atom in grams */
#define MHYDR 1.67e-24
/* solar mass in grams */
#define MSOLG 1.99e33
/* G in cgs */
#define GCGS 6.67e-8
/* kiloparsec in centimeters */
#define KPCCM 3.085678e21
/* Thompson cross-section (cm^2) */
#define SIGMAT 6.6524e-25
/* Speed of Light cm/s */
#define LIGHTSPEED 2.9979e10
#define SECONDSPERYEAR 31557600.