On 2002-11-17 00:04, amstrad wrote:
disclaimer: I am, by no means, an experienced astronomer type.
A parsec is indeed a unit of length and is equal to about 3.26 light years or 3E16 metres. A parsec is the distance (from the sun) that an object must be in order to give a parallax of one second of an arc (1/3600 of a degree).
Astronomers prefer using parsec (moreso for nearer objects) since measuring a heliocentric parallax directly measures its distance from our sun.
Useless fact: 1 attoparsec (1E-18pc) is about an inch.