unit of length used in astronomy
A parsec is a unit of distance used in astronomy. It is the distance that light travels in 3.26 years, or just under 31 trillion kilometres (about 19 trillion miles).
|Unit system||astronomical units|
|1 pc in ...||... is equal to ...|
|SI units||3.0857×1016 m|
|imperial & US units||1.9174×1013 mi|
|other astronomical||2.0626×105 AU|
This is from the definition: a parsec is the distance from the Sun to an object which has a parallax angle of one arcsecond. The technique used in the calculation is trigonometry.
It takes 3.26 years for the light to come from a parsec away.