Astronomers use several units of measurement to describe vast distances in space, as the distances between stars and galaxies are too large for conventional units like kilometers or miles. One of the most commonly used units is the light year, which is the distance that light travels in one year—approximately 9.46 trillion kilometers.
Another unit, the parsec, is used to measure distances to stars and galaxies. One parsec is about 3.26 light years. These units help astronomers study the structure of the universe, the distances between celestial objects, and the motion of galaxies and stars.