parsec

parsec

a unit of astronomical distance equal to the distance from earth at which stellar parallax would be 1 second of arc; equivalent to 3.0857 × 10¹⁶ m or 3.262 light years

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

parsec

(par -sek) Short for parallax second. Symbol: pc. A unit of length normally used for distances beyond the Solar System. It is the distance at which the semimajor axis of the Earth's orbit subtends an angle of one arc second. It is thus the distance at which a star would have an annual parallax of one arc second. A star with a parallax of p arc seconds is at a distance of d parsecs, given by d = 1/p (accurate up to distances of about 30 pc). One parsec equals 30.857 × 10¹² km, 206 265 astronomical units, and 3.2616 light-years.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

parsec

[′pär‚sek]

(astronomy)

The distance at which a star would have a parallax equal to 1 second of arc; 1 parsec equals 3.258 light-years or 3.08572 × 10¹³ kilometers. Derived from parallax-second.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

PARSEC

Extensible language with PL/I-like syntax, derived from PROTEUS. "PARSEC User's Manual", Bolt Beranek & Newman (Dec 1972).

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Parsec

 

a unit of distance in astronomy equal to 206,265 astronomical units, or 30,857 X 10¹² km; its international abbreviation is pc. Distance expressed in parsecs is the reciprocal of the annual parallax. Thus, a distance of 10 pc corresponds to a parallax of 0.1”. In fact, the name “parsec” derives from these last two values—”parallax of one second.” One parsec is equal to 3.26 light-years.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.