Distance units based on the speed of light UnitDefinitionDistance light-hour60 light-minutes = 3600 light-seconds1.079×109 km light-day24 light-hours = 86400 light-seconds2.590×1010 km light-week7 light-days = 604800 light-seconds1.813×1011 km light-year365.25 light-days = 31557600 light-seconds9.461×1012 km 3 more rows