A light hour (also written light-hour) is a unit of length. It is the distance travelled by light in vacuum in one hour. Based on the current definition of the metre a light-hour is equal to 1,079,252,848,800 metres (~1.08 Tm).
To give an example, Pluto's orbit's semi-major axis is about 5.473 light-hours.
See also: Light year
Last updated: 06-01-2005 21:14:36
Last updated: 09-12-2005 02:39:13