UNITS A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site parsec (pc) An astronomical unit of length, equal to the distance at which the radius of the Earth's orbit subtends an angle of one arcsecond. The name is a contraction of "parallax-second." 1 parsec = 3.259 light-years = 206,265 AU = 30.83 trillion km = 19.16 trillion miles. The parsec is generally used by astronomers in preference to the light-year. For larger distances, the kiloparsec (kpc) = 1,000 pc or megaparsec (Mpc) = 1,000,000 pc are used. Related category    • UNITS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP