Parsec
by Dominic Ford, Editor
Last updated: 7 Jan 2017
The parsec is a unit of length which is equal to:
\( 3.0857 \times 10^{16} \) m
\( 3.26 \) light years
\( 206,264.8 \) astronomical units
It is used to measure the very largest structures in the Universe. For example, the centre of the Milky Way galaxy lies at a distance of 8.1 kpc, where one kiloparsec equals one thousand parsecs. The distance to the nearest galaxy of a similar size to our own, the Andromeda Galaxy (M31) is around 780 kpc.