earth:
.kms_to_sun    = 150'000'000           ; orbital radius
.kms_a_year    = .kms_to_sun * 2*pi    ; orbital circle length
.light_mins_4the_orbit \
               = .kms_a_year / 300'000 / 60
.kms_a_day     = .kms_a_year / 360     ; ~365 ~366, Earth seems has changed its orbit, either rotation speed...
.kms_an_hour   = .kms_a_day / 24
.kms_a_second  = .kms_an_hour / 3600




light:
;        kms/sec   secs   hr   ~ds
.year1 = 300'000 * 3600 * 24 * 360
.year2 = 3       * 36   * 24 * 36  * 100'000'000
