Encyclopædia Galactica Rami T. F. Rekola Tuorlan Astronomical Society Tuorla Observatory University of Turku


The measure of distance used by professional astronomers. It is defined as the distance at which one AU would look one arc second wide. One parsec is therefore about 31,000 billion km (19,180 billion miles), or 3.2616 light years, or 206,265 AU.