Lightyear
A lightyear is a measure of distance. It is the distance light travels, in a vacuum, over a year. A light-year is 9,461,000,000,000 kilometres (5.879×1012 mi). A light-year is 63,241.077 astronical units.
A lightyear is a measure of distance. It is the distance light travels, in a vacuum, over a year. A light-year is 9,461,000,000,000 kilometres (5.879×1012 mi). A light-year is 63,241.077 astronical units.