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
USS PC-823 York, ROKN’s first ocean-going naval vessel, Baek-du-san (PC-701) was born. Sailing from New York, a 3-inch main deck gun was attached at the Hawaii Naval Station, and 100 shells were purchased at Guam. PC-701 finally arrived at Jinhae Naval Base, South Korea, on 10 April 1950, barely two months before the June 1950 outbreak of the Korean War. With only 100 rounds ammunition, the sailors could only practice aiming the main gun, not firing it. On the night of 25/26 June 1950, on the South Korean eastern coast, she patrolled against infiltrators from the north. About twenty miles from the