A light-year is the distance that light travels in a vacuum in one Julian year (365.25 days). It is a unit of length, not time, used to measure astronomical distances. Specifically, one light-year equals approximately 9.46 trillion kilometers (9.461 × 10¹⁵ meters) or about 5.88 trillion miles
. This distance is calculated based on the speed of light, which is about 300,000 kilometers per second (186,000 miles per second), multiplied by the number of seconds in a year. Because light travels so fast, a light-year allows astronomers to express the vast distances between stars and galaxies in a comprehensible way
