Specifically, a parsec is the distance to a star whose apparent position shifts by 1 arcsecond (1/3,600 of a degree) in the sky after Earth orbits halfway around the sun.Ī parsec amounts to about 3.26 light-years, or about 19.2 trillion miles (30.9 trillion kilometers). However, the unit of astronomical distance used more often in astronomy research is the parsec, which is a portmanteau of ' parallax' and 'arcsecond.' The term comes from the use of triangulation to determine the distance of nearby stars.
