Light-year Light-year The light-year is a unit of length used to express astronomical distances and measures about 9.46 trillion kilometres or 5.88 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. The light-year is most often used when expressing distances to stars and other distances on a galactic scale, especially in nonspecialist and popular science publications. The unit most commonly used in professional astrometry is the parsec
Kwangmyŏngsŏng-3 Unit 2 However, the launch of Kwangmyongsong 3 Unit 2 made North Korea the tenth country to place a satellite into orbit using an indigenously developed carrier rocket. The rocket was largely made using domestically produced parts and technology; this ability is seen as cause for greater concern over North Korea's ability to develop ballistic missile technology despite sanctions. The launch was announced on 1 December 2012, when the Korean Central News Agency reported that the Korean Committee of Space Technology informed them that they "[plan] to launch another working satellite, second version of Kwangmyŏngsŏng-3, manufactured by its own efforts and with