Copyright © Philip M. Parker, INSEAD. Terms of Use.
Definition: Parsec |
ParsecNoun1. A unit of astronomical length based on the distance from Earth at which stellar parallax is 1 second of arc; equivalent to 3.262 light years. Source: WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. |
| Domain | Definitions |
Computing | PARSEC Extensible language with PL/I-like syntax, derived from PROTEUS. "PARSEC User's Manual", Bolt Beranek & Newman (Dec 1972). Source: The Free On-line Dictionary of Computing. |
Aerospace | A unit of length equal to the distance from the sun to a point having a heliocentric parallax of 1 second (1"), used as a measure of stellar distance.The name parsec is derived from the words parallax second. 1 parsec = pc = 3.084 X 10E13 kilometers = 206,265 astronomical units = 3.262 light yearsAbbreviation pc. (references) |
Geography | The radius of a circle on whose circumference 1 arc-second corresponds to 1 AU. Source: European Union. (references) |
Physics | A large distance often used in astronomy, it is equal to 3.26 light years, or 3.1 1018 cm (see scientific notation). (references) |
Space | (From PARallax + SECond). A unit of distance between stars. A star would be one parsec from Earth if its (stellar) parallax (see above) were 1 second of arc. One parsec is about 3 1/4 light years. (references) |
Source: compiled by the editor from various references; see credits. | |
(From Wikipedia, the free Encyclopedia)
The parsec (abbreviated pc) is a unit of length used in astronomy. It stands for "parallax of one arc second". It is based on the method of trigonometric parallax, the most ancient and standard method of determining stellar distances. The angle subtended at a star by the mean radius of the Earth's orbit, around the Sun, is called the parallax. The parsec is defined to be the distance from the Earth of a star that has a parallax of 1 arcsecond. Alternatively, the parsec is the distance at which two objects, separated by 1 astronomical unit, appear to be separated by an angle of 1 arcsecond. It is therefore 360×60×60/2&pi AU = ~2.0626480625×105 AU =~ 3.085 677 580 666 31×1016m=~ 3.26 light years. See 1 E16 m for a list of comparable lengths and scientific notation for an explanation of the notation.
For historical reasons, astronomers usually express distances to astronomical objects in units of parsecs, instead of light years. The first direct measurements of an object at interstellar distances (of the star 61 Cygni, by Friedrich Wilhelm Bessel in 1838) were done using trigonometry using the width of the Earth's orbit as a baseline. The parsec follows naturally from this method.
There is no star whose parallax is 1 arcsec. The greater the parallax of the star the closer it is to the Earth, and the smaller its distance in parsecs. Therefore the closest star to the Earth will have the largest measured parallax. This belongs to the star Proxima Centauri, with a parallax of 0.762 arcsecs, and lying approximately 4.28 light years, or 1.3 parsecs, away from us.
The measurement of distances of celestial bodies from the Earth in parsecs is a key aspect of astrometry, the science of making positional measurements of celestial bodies.
Because of the extremely small scale of parallactic shifts, ground-based parallax methods provide reliable measurements of stellar distances of no more than 325 light years, or about 100 parsecs, corresponding to parallaxes of no less than 1/100 of 1 arcsecond, or 10 mas (1 mas or milliarcsecond = 1/1000 arcsecond).
Between 1989 and 1993 the Hipparcos satellite, launched by the European Space Agency (ESA) in 1989, measured parallaxes for about 100,000 stars, with a precision of about 0.97 mas, and obtained accurate measurements for stellar distances of around 1000 pc.
NASA's FAME satellite was due to be launched in 2004, to measure parallaxes for about 40 million stars with sufficient precision to measure stellar distances of up to 2000 pc. However, the mission's funding was withdrawn by NASA in January 2002.
The ESA's GAIA satellite, due to be launched in mid-2012, will be of sufficiently high astrometric precision to measure stellar distances to within 10% accuracy as far as the galactic centre about 8 kpc away in the Sagittarius constellation.
In the diagram above, S represents the Sun, and E the Earth at one point in its orbit.
D is an object at a distance of one parsec from the Sun.
By definition, the angle D is one arcsecond and the distance ES is one astronomical unit.
By trigonometry, the distance SD is
See also: conversion of units.
In computer science, Parsec is an XML syntax analyzer, like LarkDistances in Parsecs
One kiloparsec, abbreviated kpc, is one thousand parsecs. One megaparsec, abbreviated Mpc, is one million parsecs.
How to calculate the value of a parsec
One astronomical unit is equal to approximately 1.49568×108 km, so
The attoparsec (atto being the prefix indicating 10-18) is a unit humorously used by some hackers. It is approximately 3.1 centimetres. See also microfortnight.External links
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Parsec."
| The following table is compiled from various sources, across various languages. When English abbreviations or acronyms come from a non-English source, this is noted. | |||
| Entry | Source | Expression | Field |
Parsec | English | Parallax second | Geography, Meteorology & Standards |
Parsec | German | Parallaxensekunde | Geography, Meteorology & Standards |
Source: compiled by the editor, based on several corpora (additional references). | |||
Synonym: ParsecSynonym: secpar (n). (additional references) |
| Context | Synonyms within Context (source: adapted from Roget's Thesaurus). |
Length | Astronomical unit, AU, light-year, parsec. |
| Source: adapted from Roget's Thesaurus. | |
Crosswords: Parsec |
| Specialty definitions using "parsec": megaparsec ♦ parallax second. (references) |
| Non-English Usage: "Parsec" is also a word in the following languages with English translations in parentheses. French (parsec), Romanian (parsec). |
| Domain | Title |
Books | |
High Tech |
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Source: compiled by the editor from various references; see credits. | |
| "Parsec" is generally used as a noun (singular) -- approximately 100.00% of the time. "Parsec" is used about 7 times out of a sample of 100 million words spoken or written in English. Its rank is based on over 700,000 words used in the English language. Some parts-of-speech are not covered due to the samples used by the British National Corpus. (note: percents less than one-hundredth of one percent have been omitted) |
| Parts of Speech | Percent | Usage per 100 Million Words | Rank in English |
| Noun (singular) | 100% | 7 | 133,076 |
Source: compiled by the editor from several corpora; see credits.
| The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com. |
| Expression | Frequency per Day |
parsec | 32 |
enterprise parsec | 8 |
definition parsec | 4 |
distance parsec | 2 |
antenna parsec | 2 |
parsec space | 2 |
inc parsec | 2 |
| Source: compiled by the editor from various references; see credits. | |
| Language | Translations for "parsec"; alternative meanings/domain in parentheses. | ||||||||||||||||||||||||||||
Arabic | فرسخ نجمي. (various references) | ||||||||||||||||||||||||||||
Danish | parsec. (various references) | ||||||||||||||||||||||||||||
Dutch | parsec (parallax second), parallax seconde (parallax second). (various references) | ||||||||||||||||||||||||||||
French | parsec (parallax second). (various references) | ||||||||||||||||||||||||||||
German | pc (paper chromatography, parallax second, pc, personal computer, Polyvinyl chloride), Parsek (parallax second), Parsec (parallax second), Parallaxensekunde (parallax second). (various references) | ||||||||||||||||||||||||||||
Greek | παρσέκ. (various references) | ||||||||||||||||||||||||||||
Japanese Kanji | バ行 (Classification for Japanese verb with the dictionary form ending in "bu", par, park, park-and-ride, Parker, parking, parking area, parking driver, parking meter, parking valet, Parkinson, parse, parser, parsing, partial, partial freezing, pass, PC, percent, percentage, perceptron, percolator, percussion, pergola, personal, personal call, personal check, personal communication, personal computer, personal opinion, personal selling, personality, perspective, purge, purse, purser). (various references) | ||||||||||||||||||||||||||||
Japanese Katakana | パーセク . (various references) | ||||||||||||||||||||||||||||
Pig Latin | arsecpay parsec. (various references) parsec. (various references) парсек. (various references) parsec. (various references) | ||||||||||||||||||||||||||||
Derivations | |
Words beginning with "parsec": parsecs. (additional references) | |
Words ending with "parsec": kiloparsec, megaparsec. (additional references) | |
Words containing "parsec": kiloparsecs, megaparsecs. (additional references) | |
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"Parsec" is suggested in spellcheckers for the following: aprec, parece, Paresce, parqe, parsim, partech, Partspck, Parystec, Pasik, pasrsec, passic, Paussac, Pearsey, Perec, perisic, perseu, persicum, Pertec, pisac, Porec, Puraspec. (additional references) | |
| Source: compiled by the editor, based on several corpora (additional references). | |
Scrabble® Enable2K-Verified Anagrams | |
Direct Anagrams: capers, crapes, escarp, pacers, recaps, scrape, secpar, spacer. | |
| Words within the letters "a-c-e-p-r-s" | |
-1 letter: acres, apers, apres, asper, caper, capes, cares, carps, carse, crape, craps, escar, pacer, paces, pares, parse, pears, prase, presa, races, rapes, reaps, recap, scape, scare, scarp, scrap, serac, space, spare, spear. | |
-2 letters: aces, acre, aper, apes, apse, arcs, ares, arse, cape, caps, care, carp, cars, case, ceps, crap, ears, eras, pace, pacs, pare, pars, pase, pear, peas, pecs, race, rape, raps, rase, rasp, reap, recs, reps, scar, sear, sera, spae, spar, spec. | |
-3 letters: ace, ape, arc, are, ars, asp, cap, car, cep, ear, era, ers, pac, par, pas, pea, pec, per, pes, rap, ras, rec, rep, res, sac, sae, sap, sea, sec, ser, spa. | |
-4 letters: ae, ar, as, er, es, pa, pe, re. | |
| Words containing the letters "a-c-e-p-r-s" | |
+1 letter: apercus, campers, cappers, carpels, carpers, carpets, clasper, eparchs, escaper, escarps, packers, parcels, parches, parsecs, placers, prances, preacts, precast, reclasp, redcaps, repacks, respace, scalper, scamper, scarped, scarper, scauper, scraped, scraper, scrapes, scrapie, secpars, spacers, spacier, spectra. | |
+2 letters: airscape, airspace, aspheric, calipers, caperers, caprices, capsomer, captures, champers, chapters, clampers, clappers, claspers, compares, copperas, crappers, crappies, crispate, epicarps, escapers, escarped, exocarps, mesocarp, pancreas, parchesi, parecism, paretics, patchers, peachers, peracids, percales, perisarc, picrates, piracies, poachers, postrace, practise, prancers, preaches, precasts, precrash, prefaces, prepacks, purchase, reclasps, replaces, replicas, respaced, respaces, sapremic, scalpers, scampers, scarpers, scarphed, scaupers, sceptral, scorepad, scrapers, scrapies, scrapped, scrapper, scrapple, seraphic, spectral, specular, spiracle, supercar. | |
+3 letters: accepters, acceptors, aerospace, airscapes, airspaces, aruspices, ascospore, becarpets, callipers, calypters, campfires, camphires, camporees, canephors, capeworks, capmakers, caponiers, caprioles, capsomers, capturers, carapaces, carapaxes, caryopses, catnapers, chaperons, chapiters, clepsydra, coappears, compadres, comparers, coparents, copperahs, copremias, copyreads, crappiest, creamcups, creepages, earpieces, endocarps, eparchies, escarping, esperance, heptarchs, impacters, mesocarps, operatics, outcapers, pacifiers, packagers, packhorse, parceners, parchesis, parecisms, parlances, particles, peccaries, pectorals, peculiars, pentarchs, perfectas, pericarps, perisarcs, picadores, piscaries, placaters, portances, practices, practised, practises, praecipes, praefects, praelects, preachers, precisian, precleans, preclears, precrease, preenacts, prefacers, prelacies, preplaces, primacies, privacies, procaines, proscenia, purchased, purchaser, purchases, pursuance, reaccepts, recarpets, reclasped, repatches, replacers, replicase, respacing, sapsucker, scalloper, scampered, scarpered, scorepads, scrapheap, scrappage, scrappers, scrappier, scrapples, sharecrop, spaceport, spaceward, specialer, spectator, spermatic, spherical, spiracles, supercars, superrace, supremacy, unpackers, uppercase, upreaches. | |
+4 letters: accipiters, acrophobes, aeciospore, aerospaces, afterclaps, apocarpies, applecarts, approaches, archetypes, archpriest, ascospores, ascriptive, aspherical, campestral, carpenters, carpetbags, carpetings, carpoolers, carpospore, cartoppers, catnappers, chaparejos, chaperones, clepsydrae, clepsydras, compacters, cooperages, cooperates, copartners, copperases, coryphaeus, crawlspace, creampuffs, crepitates, crispbread, cupbearers, curlpapers, cyberspace, deprecates, discrepant, dispatcher, drupaceous, epicureans, epigastric, escarpment, esperances, fireplaces, graphemics, hairpieces, haruspices, hydrospace, hyperspace, imprecates, interspace, kiloparsec, landscaper, marchpanes, mascarpone, megaparsec, megasporic, mercaptans, metacarpus, narcolepsy, operculars, pacemakers, pacesetter, pachyderms, packhorses, pancreases, panegyrics, paperbacks, parachutes, paramedics, parbuckles, parchments, paregorics, parfleches, parricides, parritches, pasticheur, patricides, peculators, pederastic, pediatrics, pelycosaur, percalines, percolates, pharmacies, picaresque, porcelains, practicers, preachiest, precancels, precarious, precasting, precisians, precreased, precreases, predaceous, predacious, predecease, predicates, prefascist, procreates, purchasers, pursuances, quadriceps, radarscope, ragpickers, rampancies, rapacities, recaptures, reclasping, repacifies, repackages, repechages, replicases, replicates, reproaches, repurchase, retropacks, saprogenic, sapsuckers, scallopers, scampering, scapegrace, scarpering, scorpaenid, scrapheaps, scrappages, scrappiest, screenplay, sepulchral, sharecrops, skyscraper, spacecraft, spaceports, spectators, spectrally, specularly, speculator, spermaceti, subchapter, supercargo, superclass, superclean, superflack, supermacho, superraces, superscale, syncarpies, taperstick, uppercased, uppercases, waterscape, workplaces. | |
+5 letters: absorptance, acropolises, acupressure, aeciospores, afterpieces, altarpieces, amphimacers, apicultures, appearances, apperceives, appreciates, apprentices, archesporia, archpriests, arthroscope, atmospheric, backpackers, backslapper, baroceptors, birthplaces, camelopards, campaigners, camphorates, caparisoned, capillaries, cardplayers, cardsharper, carpentries, carpetweeds, carpophores, carpospores, caryopsides, catastrophe, catchphrase, ceratopsian, chairperson, champerties, champertous, chrysoprase, colportages, compensator, complainers, compradores, comradeship, cooperators, coparceners, copperheads, copyreaders, crapshooter, crawlspaces, crepuscular, crispbreads, cyberspaces, depreciates, discrepancy, dispatchers, escarpments, explicators, gastroscope, graphicness, grapholects, hectographs, heptachlors, heptarchies, hippocrases, hydrospaces, hyperspaces, hyperstatic, importances, intercampus, interspaced, interspaces, kiloparsecs, landscapers, laparoscope, leprechauns, letterspace, macrophages, macrophytes, mascarpones, masterpiece, megaparsecs, metacarpals, microphages, outpreaches, pacesetters, packthreads, paediatrics, pancreatins, parameciums, paraplegics, parcenaries, parenchymas, paresthetic, participles, pasticheurs, patriciates, peacemakers, pearlescent, pelycosaurs, penetrances, pentarchies, percentages, percolators, periodicals, peristaltic, permanences, picaresques, plasticizer, polariscope, pratincoles, preachifies, preachiness, preachments, precalculus, precautions, precreasing, predacities, predeceased, predeceases, predicables, predynastic, prefascists, prefinances, pregnancies, prepackages, prepurchase, presynaptic, prevalences, procaryotes, procedurals, processable, proclaimers, procreators, procrustean, protectants, prothoraces, provenances, purchasable, purtenances, purveyances, pyromancies, radarscopes, receptacles, reciprocals, recuperates, relandscape, repackagers, repentances, replicators, reproachers, reprobances, republicans, repugnances, repurchased, repurchases, respectable, respectably, ropedancers, scapegraces, scenography, scolopendra, scorpaenids, scrappiness, screenplays, skyscrapers, spacecrafts, spacewalker, spatterdock, spectacular, spectrogram, specularity, speculators, spermacetis, spermatheca, spermicidal, spherically, spirochaete, spirochetal, streetscape, subchapters, superagency, supercargos, supercharge, superficial, superflacks, superjacent, supermachos, superscales, supremacies, supremacist, tapersticks, temperances, tetrasporic, transpierce, triceratops, triplicates, uppercasing, waterscapes. | |
| Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro. | |
Hexadecimal (or equivalents, 770AD-1900s) (references)50 61 72 73 65 63 |
| Leonardo da Vinci (1452-1519; backwards) (references)
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| American Sign Language (origins from 1620-1817 in Italy and, especially, France) (references)
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| Semaphore (1791, in France) (references)
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| Braille (1829, in France) (references)
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Morse Code (1836) (references).--. .- .-. ... . -.-. |
| Dancing Men (Sir Arthur Conan Doyle, 1903) (references)
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Binary Code (1918-1938, probably earlier) (references)01010000 01100001 01110010 01110011 01100101 01100011 |
HTML Code (1990) (references)P a r s e c |
ISO 10646 (1991-1993) (references)0050 0061 0072 0073 0065 0063 |
| British Sign Language (Fingerspelling, BSL; 1992, British Deaf Association Dictionary of British Sign Language) (references)
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Encryption (beginner's substitution cypher): (references)506784857169 |
| 1. Definition 2. Synonyms 3. Crosswords 4. Usage: Commercial | 5. Usage Frequency 6. Expressions: Internet 7. Translations: Modern 8. Abbreviations | 9. Acronyms 10. Derivations 11. Anagrams 12. Orthography | 13. Bibliography |
Copyright © Philip M. Parker, INSEAD. Terms of Use.
