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The light-hour, or light hour, is an astronomical unit of distance defined as the distance that light travels in free space (or vacuum) in one hour.
The light-hour is equal to 1.079252849 × 1012 meters (1 light-hour = 1.079252849 × 1012 m), the base unit of length in the International System of Units (SI). The light-hour is also equal to 1.079 × 109 kilometers (km) (an SI unit of length), or approximately 6.706 × 108 miles (mi) or 3.54086 × 1012 feet (ft), which are US customary / Imperial units of length.
The light-hour along with light-second, light-minute and light-day are used in popular science publications. One light-hour is equal to 3,600 light-seconds, or 60 light-minutes, or about 0.041667 light-days or 1.1408 × 10-4 light-years.