2 #include <gsl/gsl_const_mksa.h>
7 double c = GSL_CONST_MKSA_SPEED_OF_LIGHT;
8 double au = GSL_CONST_MKSA_ASTRONOMICAL_UNIT;
9 double minutes = GSL_CONST_MKSA_MINUTE;
11 /* distance stored in meters */
12 double r_earth = 1.00 * au;
13 double r_mars = 1.52 * au;
17 t_min = (r_mars - r_earth) / c;
18 t_max = (r_mars + r_earth) / c;
20 printf ("light travel time from Earth to Mars:\n");
21 printf ("minimum = %.1f minutes\n", t_min / minutes);
22 printf ("maximum = %.1f minutes\n", t_max / minutes);