He passed the preliminary and went on to the finals. a boxing match or other athletic contest that takes place before the main event on the program: A preliminary was fought at 8:00. a preliminary examination, as of a candidate for an academic degree.
A light year is a measure of distance, or the distance a particle of light will travel through a pure vacuum in one Earth year. This distance is approximately 5.8785 x 1012 [5.87 trillion] miles, or 9.4605 x 1012 [9.46 trillion] kilometers.n one year, light can travel about 10 trillion km. One light-year is equal to 9,500,000,000,000 kilometers. A light year is the distance covered by light in one year travelling at 186,000 miles per second.
Look up light year in Wiktionary, the free dictionary. A light-year (or light year, abbreviation: ly) is a unit of length used informally to express astronomical distances. It is approximately 9 petametres, or 9 trillion kilometres (or about 6 trillion miles). As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Because it includes the word year, the term light-year is sometimes misinterpreted as a unit of time.