rdfs:comment
| - A light-second is a unit of length useful in astronomy, telecommunications, and relativistic physics. It is defined as the distance that light travels in free space in one second, and is equal to exactly 299,792,458 meters. It is just over 186,000 miles and almost 109 feet.
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abstract
| - A light-second is a unit of length useful in astronomy, telecommunications, and relativistic physics. It is defined as the distance that light travels in free space in one second, and is equal to exactly 299,792,458 meters. It is just over 186,000 miles and almost 109 feet. Just as the second forms the basis for other units of time, the light-second can form the basis for other units of length, ranging from the light-nanosecond (just under one U.S. or imperial foot) to the light-minute, light-hour, and light-day, which are sometimes used in popular science publications. The more commonly-used light-year is also presently defined to be equal to precisely 31557600 light-seconds, since the definition of a year is based on a Julian year (not Gregorian year) of exactly 365.25 days, each of exactly 86400 SI seconds.
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