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109-504: The term quasar originated as a contraction of "quasi-stellar [star-like] radio source"—because they were first identified during the 1950s as sources of radio-wave emission of unknown physical origin—and when identified in photographic images at visible wavelengths, they resembled faint, star-like points of light. High-resolution images of quasars, particularly from the Hubble Space Telescope , have shown that quasars occur in

218-498: A white hole end of a wormhole , or a chain reaction of numerous supernovae . Eventually, starting from about the 1970s, many lines of evidence (including the first X-ray space observatories , knowledge of black holes and modern models of cosmology ) gradually demonstrated that the quasar redshifts are genuine and due to the expansion of space , that quasars are in fact as powerful and as distant as Schmidt and some other astronomers had suggested, and that their energy source

327-464: A black hole converts between 6% and 32% of the mass to energy, compared to 0.7% for the conversion of mass to energy in a star like the Sun. It is the only process known that can produce such high power over a very long term. (Stellar explosions such as supernovas and gamma-ray bursts , and direct matter – antimatter annihilation, can also produce very high power output, but supernovae only last for days, and

436-421: A black hole. The energy produced by a quasar is generated outside the black hole, by gravitational stresses and immense friction within the material nearest to the black hole, as it orbits and falls inward. The huge luminosity of quasars results from the accretion discs of central supermassive black holes, which can convert between 5.7% and 32% of the mass of an object into energy , compared to just 0.7% for

545-545: A breakthrough in 1962. Another radio source, 3C 273 , was predicted to undergo five occultations by the Moon . Measurements taken by Cyril Hazard and John Bolton during one of the occultations using the Parkes Radio Telescope allowed Maarten Schmidt to find a visible counterpart to the radio source and obtain an optical spectrum using the 200-inch (5.1 m) Hale Telescope on Mount Palomar . This spectrum revealed

654-515: A collaboration of scientists, related to the Event Horizon Telescope , presented, for the first time, a polarized-based image of a black hole , specifically the black hole at the center of Messier 87 , an elliptical galaxy approximately 55 million light-years away in the constellation Virgo , revealing the forces giving rise to quasars. It is now known that quasars are distant but extremely luminous objects, so any light that reaches

763-469: A contraction of 不 (bù) + 唯/隹 (wéi/zhuī). The contractions are not generally graphically evident, and there is no general rule for how a character representing a contraction might be formed. As a result, the identification of a character as a contraction, as well as the word(s) that are proposed to have been contracted, is sometimes disputed. As vernacular Chinese dialects use sets of function words that differ considerably from Classical Chinese , almost all of

872-411: A definite direct object, and the definite article prefix -ה (/ha-/) are often contracted to 'ת (/ta-/) when the former immediately precedes the latter; thus, ראיתי את הכלב (/ʁaˈʔiti ʔet haˈkelev/, "I saw the dog") may become ראיתי ת'כלב (/ʁaˈʔiti taˈkelev/). In Italian , prepositions merge with direct articles in predictable ways. The prepositions a , da , di , in , su , con and per combine with

981-432: A distant active galactic nucleus. He stated that a distant and extremely powerful object seemed more likely to be correct. Schmidt's explanation for the high redshift was not widely accepted at the time. A major concern was the enormous amount of energy these objects would have to be radiating, if they were distant. In the 1960s no commonly accepted mechanism could account for this. The currently accepted explanation, that it

1090-439: A few arcseconds or less), they are commonly referred to as a "double quasar". When the two are also close together in space (i.e. observed to have similar redshifts), they are termed a "quasar pair", or as a "binary quasar" if they are close enough that their host galaxies are likely to be physically interacting. As quasars are overall rare objects in the universe, the probability of three or more separate quasars being found near

1199-450: A measurement grid on the sky. The International Celestial Reference System (ICRS) is based on hundreds of extra-galactic radio sources, mostly quasars, distributed around the entire sky. Because they are so distant, they are apparently stationary to current technology, yet their positions can be measured with the utmost accuracy by very-long-baseline interferometry (VLBI). The positions of most are known to 0.001 arcsecond or better, which

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1308-534: A name which reflected their unknown nature, and this became shortened to "quasar". The first quasars ( 3C 48 and 3C 273 ) were discovered in the late 1950s, as radio sources in all-sky radio surveys. They were first noted as radio sources with no corresponding visible object. Using small telescopes and the Lovell Telescope as an interferometer , they were shown to have a very small angular size. By 1960, hundreds of these objects had been recorded and published in

1417-450: A particular kind of active galaxy , and a consensus emerged that in many cases it is simply the viewing angle that distinguishes them from other active galaxies, such as blazars and radio galaxies . The highest-redshift quasar known (as of August 2024) is UHZ1 , with a redshift of approximately 10.1, which corresponds to a comoving distance of approximately 31.7 billion light-years from Earth (these distances are much larger than

1526-473: A portmanteau word is formed by combining two or more existing words that all relate to a singular concept that the portmanteau describes. English has a number of contractions, mostly involving the elision of a vowel, which is replaced by an apostrophe in writing, as in I'm for "I am", and sometimes other changes as well. Contractions are common in speech and in informal writing but tend to be avoided in more formal writing (with limited exceptions, such as

1635-570: A quasar finishes accreting the surrounding gas and dust, it becomes an ordinary galaxy. Radiation from quasars is partially "nonthermal" (i.e., not due to black-body radiation ), and approximately 10% are observed to also have jets and lobes like those of radio galaxies that also carry significant (but poorly understood) amounts of energy in the form of particles moving at relativistic speeds . Extremely high energies might be explained by several mechanisms (see Fermi acceleration and Centrifugal mechanism of acceleration ). Quasars can be detected over

1744-439: A redshift of 0.367, one of the highest redshifts of any source known at the time. It was not until 1982 that a surrounding faint galactic "nebula" was measured to have the same redshift as 3C 48, confirming its identification as an object in a distant galaxy. This was also the first reliable identification of a quasar with a surrounding galaxy of the same redshift. On September 26, 1960, Matthews and Sandage photographed an area of

1853-663: A special form is used when combining con with mí, ti, or sí, which is written as conmigo for * con mí (with me), contigo for * con ti (with you sing.), consigo for * con sí (with himself/herself/itself/themselves (themself).) Finally, one can hear pa' for para , deriving as pa'l for para el , but these forms are only considered appropriate in informal speech. In Portuguese , contractions are common and much more numerous than those in Spanish. Several prepositions regularly contract with certain articles and pronouns. For instance, de (of) and por (by; formerly per ) combine with

1962-525: A substantial fraction of the light was emitted from a region less than 1 light-year in size, tiny compared to a galaxy. Although it raised many questions, Schmidt's discovery quickly revolutionized quasar observation. The strange spectrum of 3C 48 was quickly identified by Schmidt, Greenstein and Oke as hydrogen and magnesium redshifted by 37%. Shortly afterwards, two more quasar spectra in 1964 and five more in 1965 were also confirmed as ordinary light that had been redshifted to an extreme degree. While

2071-399: A suitable mechanism could not be confirmed to exist in nature. By 1987 it was "well accepted" that this was the correct explanation for quasars, and the cosmological distance and energy output of quasars was accepted by almost all researchers. Later it was found that not all quasars have strong radio emission; in fact only about 10% are "radio-loud". Hence the name "QSO" (quasi-stellar object)

2180-420: A supermassive black hole would have to consume the material equivalent of 10 solar masses per year. The brightest known quasars devour 1000 solar masses of material every year. The largest known is estimated to consume matter equivalent to 10 Earths per second. Quasar luminosities can vary considerably over time, depending on their surroundings. Since it is difficult to fuel quasars for many billions of years, after

2289-413: A time scale as to allow the coordination of the luminosity variations. This would mean that a quasar varying on a time scale of a few weeks cannot be larger than a few light-weeks across. The emission of large amounts of power from a small region requires a power source far more efficient than the nuclear fusion that powers stars. The conversion of gravitational potential energy to radiation by infalling to

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2398-483: A verb), te → t'- (informal singular "you" before a verb), le or la → l'- ("the"; or "he", "she", "it" before a verb or after an imperative verb and before the word y or en ), and de → d'- ("of"). Unlike with English contractions, however, thoose contractions are mandatory: one would never say (or write) *ce est or *que elle . Moi ("me") and toi (informal "you") mandatorily contract to m'- and t'- , respectively, after an imperative verb and before

2507-407: A vowel, h or y (as h is silent and absorbed by the sound of the succeeding vowel; y sounds like i ). In addition to ce → c'- (demonstrative pronoun "that"), these words are que → qu'- (conjunction, relative pronoun, or interrogative pronoun "that"), ne → n'- ("not"), se → s'- ("himself", "herself", "itself", "oneself" before a verb), je → j'- ("I"), me → m'- ("me" before

2616-639: A él , meaning to him , and de él , meaning his or, more literally, of him ). Other contractions were common in writing until the 17th century , the most usual being de + personal and demonstrative pronouns: destas for de estas (of these, fem.), daquel for de aquel (of that, masc.), dél for de él (of him) etc.; and the feminine article before words beginning with a- : l'alma for la alma , now el alma (the soul). Several sets of demonstrative pronouns originated as contractions of aquí (here) + pronoun, or pronoun + otro/a (other): aqueste , aqueso , estotro etc. The modern aquel (that, masc.)

2725-419: Is "Det ordner seg av seg selv" in standard written Bokmål , meaning "It will sort itself out" could become "dånesæsæsjæl" (note the letters Å and Æ , and the word "sjæl", as an eye dialect spelling of selv ). R-dropping , being present in the example, is especially common in speech in many areas of Norway , but plays out in different ways, as does elision of word-final phonemes like /ə/ . Because of

2834-480: Is apparent graphically. Similarly, in Northeastern Mandarin 甭 (béng) 'needn't' is a phonological and graphical contraction of 不用 (bùyòng). Finally, Cantonese contracts 乜嘢 (mat1 ye5) 'what?' to 咩 (me1). Note: The particles 爰, 焉, 云, and 然 ending in [-j[a/ə]n] behave as the grammatical equivalents of a verb (or coverb) followed by 之 'him; her; it (third-person object)' or a similar demonstrative pronoun in

2943-453: Is dat?" - what is that?. Some of these contractions: French has a variety of contractions like in English except that they are mandatory, as in C'est la vie ("That's life") in which c'est stands for ce + est ("that is"). The formation of such contractions is called elision . In general, any monosyllabic word ending in e caduc (schwa) contracts if the following word begins with

3052-463: Is due to matter in an accretion disc falling into a supermassive black hole , was only suggested in 1964 by Edwin E. Salpeter and Yakov Zeldovich , and even then it was rejected by many astronomers, as at this time the existence of black holes at all was widely seen as theoretical. Various explanations were proposed during the 1960s and 1970s, each with their own problems. It was suggested that quasars were nearby objects, and that their redshift

3161-810: Is left to a great extent to authors and their publishers. Outside quotations, at least, they usually pay little attention to print more than the most commonly spoken contractions, so as not to degrade their readability. The use of apostrophes to indicate omissions is a varying and considerably less frequent process than in English-language publications. In standard Indonesian, there are no contractions applied, although Indonesian contractions exist in Indonesian slang . Many of these contractions are terima kasih to makasih ("thank you"), kenapa to napa ("why"), nggak to gak ("not"), sebentar to tar ("a moment"), and sudah to dah ("done"). The use of contractions

3270-420: Is matter from an accretion disc falling onto a supermassive black hole. This included crucial evidence from optical and X-ray viewing of quasar host galaxies, finding of "intervening" absorption lines, which explained various spectral anomalies, observations from gravitational lensing , Gunn 's 1971 finding that galaxies containing quasars showed the same redshift as the quasars, and Kristian 's 1973 finding that

3379-495: Is not allowed in any form of standard Norwegian spelling; however, it is fairly common to shorten or contract words in spoken language. Yet, the commonness varies from dialect to dialect and from sociolect to sociolect—it depends on the formality etc. of the setting. Some common, and quite drastic, contractions found in Norwegian speech are "jakke" for "jeg har ikke", meaning "I do not have" and "dække" for "det er ikke", meaning "there

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3488-484: Is not". The most frequently used of these contractions—usually consisting of two or three words contracted into one word, contain short, common and often monosyllabic words like jeg , du , deg , det , har or ikke . The use of the apostrophe (') is much less common than in English, but is sometimes used in contractions to show where letters have been dropped. In extreme cases, long, entire sentences may be written as one word. An example of this

3597-437: Is now thought that all large galaxies have a black hole of this kind, but only a small fraction have sufficient matter in the right kind of orbit at their center to become active and power radiation in such a way as to be seen as quasars. This also explains why quasars were more common in the early universe, as this energy production ends when the supermassive black hole consumes all of the gas and dust near it. This means that it

3706-416: Is often true of other words of similar form, e.g. quale . The direct object pronouns "lo" and "la" may also contract to form "l'" with a form of "avere", such as "L'ho comprato" - "I have bought it", or "L'abbiamo vista" - "We have seen her". Spanish has two mandatory phonetic contractions between prepositions and articles: al (to the) for a el , and del (of the) for de el (not to be confused with

3815-445: Is orders of magnitude more precise than the best optical measurements. A grouping of two or more quasars on the sky can result from a chance alignment, where the quasars are not physically associated, from actual physical proximity, or from the effects of gravity bending the light of a single quasar into two or more images by gravitational lensing . When two quasars appear to be very close to each other as seen from Earth (separated by

3924-503: Is possible that most galaxies, including the Milky Way, have gone through an active stage, appearing as a quasar or some other class of active galaxy that depended on the black-hole mass and the accretion rate, and are now quiescent because they lack a supply of matter to feed into their central black holes to generate radiation. The matter accreting onto the black hole is unlikely to fall directly in, but will have some angular momentum around

4033-454: Is preserved in the verb nolo (I am unwilling/do not want), which was formed by a contraction of non volo ( volo meaning "I want"). Similarly this is observed in the first person plural and third person plural forms (nolumus and nolunt respectively). Some contractions in rapid speech include ～っす ( -ssu ) for です ( desu ) and すいません ( suimasen ) for すみません ( sumimasen ). では ( dewa ) is often contracted to じゃ ( ja ). In certain grammatical contexts

4142-406: Is similar to English ones is the combination of the pronoun da with words starting in a , resulting in changing the first letter a for an apostrophe and joining both words. Examples: Estrela d'alva (A popular phrase to refer to Venus that means "Alb star", as a reference to its brightness); Caixa d'água (water tank). In informal, spoken German prepositional phrases , one can often merge

4251-551: Is spoken as Samma, Meesta, kamma hier ma rin? Several West Central German dialects along the Rhine River have built contraction patterns involving long phrases and entire sentences. In speech, words are often concatenated, and frequently the process of "liaison" is used. So, [Dat] kriegst Du nicht may become Kressenit , or Lass mich gehen, habe ich gesagt may become Lomejon haschjesaat . Mostly, there are no binding orthographies for local dialects of German, hence writing

4360-459: Is statistically certain that thousands of energy jets should be pointed toward the Earth, some more directly than others. In many cases it is likely that the brighter the quasar, the more directly its jet is aimed at the Earth. Such quasars are called blazars . The hyperluminous quasar APM 08279+5255 was, when discovered in 1998, given an absolute magnitude of −32.2. High-resolution imaging with

4469-412: Is the only survivor of the first pattern; the personal pronouns nosotros (we) and vosotros (pl. you) are remnants of the second. In medieval texts, unstressed words very often appear contracted: todol for todo el (all the, masc.), ques for que es (which is); etc. including with common words, like d'ome (d'home/d'homme) instead de ome (home/homme), and so on. Though not strictly a contraction,

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4578-423: Is used (in addition to "quasar") to refer to these objects, further categorized into the "radio-loud" and the "radio-quiet" classes. The discovery of the quasar had large implications for the field of astronomy in the 1960s, including drawing physics and astronomy closer together. In 1979, the gravitational lens effect predicted by Albert Einstein 's general theory of relativity was confirmed observationally for

4687-513: Is used as a possessive pronoun) and jemu , respectively. The clitic -ń , which stands for niego (him), as in dlań ( dla niego ), is more common in literature. The non-contracted forms are generally used as a means to accentuate. Uyghur , a Turkic language spoken in Central Asia , includes some verbal suffixes that are actually contracted forms of compound verbs ( serial verbs ). For instance, sëtip alidu (sell-manage, "manage to sell")

4796-527: Is used to indicate obligation. It is often used without an auxiliary, e.g., 行かなきゃ（いけない） ( ikanakya (ikenai) ) "I have to go." Other times, contractions are made to create new words or to give added or altered meaning: Various dialects of Japanese also use their own specific contractions that are often unintelligible to speakers of other dialects. In Polish , pronouns have contracted forms that are more prevalent in their colloquial usage. Examples are go and mu . The non-contracted forms are jego (unless it

4905-400: Is usually written and pronounced sëtivaldu , with the two words forming a contraction and the [p] leniting into a [v] or [w]. In Filipino, most contractions need other words to be contracted correctly. Only words that end with vowels can make a contraction with words like "at" and "ay." In this chart, the "@" represents any vowel. 3C 48 3C48 is a quasar discovered in 1960; it

5014-417: The [s] of sais . It is also common in informal contexts to contract tu to t'- before a vowel: t'as mangé for tu as mangé . In Modern Hebrew , the prepositional prefixes -בְּ /bə-/ 'in' and -לְ /lə-/ 'to' contract with the definite article prefix -ה (/ha-/) to form the prefixes -ב /ba/ 'in the' and -ל /la/ 'to the'. In Colloquial Israeli Hebrew]], the preposition את (/ʔet/), which indicates

5123-558: The American Astronomical Society . Testing the hypothesis that 3C48 is a stellar remnant of a nova or even a supernova ("the first true radio star "), H. Smith and D. Hoffleit looked through the Harvard Sky Survey's collection of plates for 1897-1958 and did not find any noticeable fluctuations in the object's brightness exceeding 0.3m, which are common in former novae. The most likely possibility seemed to be that it

5232-508: The Earth is redshifted due to the expansion of the universe . Quasars inhabit the centers of active galaxies and are among the most luminous, powerful, and energetic objects known in the universe, emitting up to a thousand times the energy output of the Milky Way , which contains 200–400 billion stars. This radiation is emitted across the electromagnetic spectrum almost uniformly, from X-rays to

5341-436: The Hubble Space Telescope and the 10 m Keck Telescope revealed that this system is gravitationally lensed . A study of the gravitational lensing of this system suggests that the light emitted has been magnified by a factor of ~10. It is still substantially more luminous than nearby quasars such as 3C 273. Quasars were much more common in the early universe than they are today. This discovery by Maarten Schmidt in 1967

5450-631: The Third Cambridge Catalogue while astronomers scanned the skies for their optical counterparts. In 1963, a definite identification of the radio source 3C 48 with an optical object was published by Allan Sandage and Thomas A. Matthews . Astronomers had detected what appeared to be a faint blue star at the location of the radio source and obtained its spectrum, which contained many unknown broad emission lines. The anomalous spectrum defied interpretation. British-Australian astronomer John Bolton made many early observations of quasars, including

5559-419: The centers of galaxies , and that some host galaxies are strongly interacting or merging galaxies. As with other categories of AGN, the observed properties of a quasar depend on many factors, including the mass of the black hole, the rate of gas accretion, the orientation of the accretion disc relative to the observer, the presence or absence of a jet , and the degree of obscuration by gas and dust within

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5668-643: The chemical elements of which the object is composed, were also extremely strange and defied explanation. Some of them changed their luminosity very rapidly in the optical range and even more rapidly in the X-ray range, suggesting an upper limit on their size, perhaps no larger than the Solar System . This implies an extremely high power density . Considerable discussion took place over what these objects might be. They were described as "quasi-stellar [meaning: star-like] radio sources" , or "quasi-stellar objects" (QSOs),

5777-512: The p–p chain nuclear fusion process that dominates the energy production in Sun-like stars. Central masses of 10 to 10 solar masses have been measured in quasars by using reverberation mapping . Several dozen nearby large galaxies, including the Milky Way galaxy, that do not have an active center and do not show any activity similar to a quasar, are confirmed to contain a similar supermassive black hole in their nuclei (galactic center) . Thus it

5886-410: The spectrum of the object. It contained an unusual combination of broad emission lines that defied identification. The color indices of 3C48 were also unusual: Sandage found that they were consistent with hot white dwarfs and former Nova - very hot objects with an ultraviolet excess. In December 1960, Sandage reported the results of the first optical observations of 3C48 at the 107th meeting of

5995-441: The "fuzzy" surrounding of many quasars was consistent with a less luminous host galaxy. This model also fits well with other observations suggesting that many or even most galaxies have a massive central black hole. It would also explain why quasars are more common in the early universe: as a quasar draws matter from its accretion disc, there comes a point when there is less matter nearby, and energy production falls off or ceases, as

6104-432: The Milky Way. But when radio astronomy began in the 1950s, astronomers detected, among the galaxies, a small number of anomalous objects with properties that defied explanation. The objects emitted large amounts of radiation of many frequencies, but no source could be located optically, or in some cases only a faint and point-like object somewhat like a distant star . The spectral lines of these objects, which identify

6213-400: The Sun, or about 100 times that of the total light of giant galaxies like the Milky Way . This assumes that the quasar is radiating energy in all directions, but the active galactic nucleus is believed to be radiating preferentially in the direction of its jet. In a universe containing hundreds of billions of galaxies, most of which had active nuclei billions of years ago but only seen today, it

6322-499: The [-n] ending is derived from a Sino-Tibetan aspect marker that later took on anaphoric character. Here are some of the contractions in Standard Dutch : Informal Belgian Dutch uses a wide range of non-standard contractions such as "hoe's't" (from "hoe is het?" - how are you?), "hij's d'r" (from "hij is daar" - he's there), "w'ebbe' goe' g'ete'" (from "we hebben goed gegeten" - we had eaten well) and "wa's da'?" (from "wat

6431-942: The apostrophe) in certain contexts. For example, the greeting Wie geht es? is usually encountered in the contracted form Wie geht's? . Regional dialects of German, and various local languages that usually were already used long before today's Standard German was created, do use contractions usually more frequently than German, but varying widely between different local languages. The informally spoken German contractions are observed almost everywhere, most often accompanied by additional ones, such as in den becoming in'n (sometimes im ) or haben wir becoming hamwer , hammor , hemmer , or hamma depending on local intonation preferences. Bavarian German features several more contractions such as gesund sind wir becoming xund samma , which are schematically applied to all word or combinations of similar sound. (One must remember, however, that German wir exists alongside Bavarian mir , or mia , with

6540-592: The background of the universe. Schmidt noted that redshift is also associated with the expansion of the universe, as codified in Hubble's law . If the measured redshift was due to expansion, then this would support an interpretation of very distant objects with extraordinarily high luminosity and power output, far beyond any object seen to date. This extreme luminosity would also explain the large radio signal. Schmidt concluded that 3C 273 could either be an individual star around 10 km wide within (or near to) this galaxy, or

6649-512: The black hole, which will cause the matter to collect into an accretion disc . Quasars may also be ignited or re-ignited when normal galaxies merge and the black hole is infused with a fresh source of matter. In fact, it has been suggested that a quasar could form when the Andromeda Galaxy collides with the Milky Way galaxy in approximately 3–5 billion years. In the 1980s, unified models were developed in which quasars were classified as

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6758-484: The brightest lines. The atoms emitting these lines range from neutral to highly ionized, leaving it highly charged. This wide range of ionization shows that the gas is highly irradiated by the quasar, not merely hot, and not by stars, which cannot produce such a wide range of ionization. Like all (unobscured) active galaxies, quasars can be strong X-ray sources. Radio-loud quasars can also produce X-rays and gamma rays by inverse Compton scattering of lower-energy photons by

6867-412: The centers of clusters of galaxies are known to have enough power to prevent the hot gas in those clusters from cooling and falling on to the central galaxy. Quasars' luminosities are variable, with time scales that range from months to hours. This means that quasars generate and emit their energy from a very small region, since each part of the quasar would have to be in contact with other parts on such

6976-521: The classical contractions that are listed below are now archaic and have disappeared from everyday use. However, modern contractions have evolved from the new vernacular function words. Modern contractions appear in all major modern dialect groups. For example, 别 (bié) 'don't' in Standard Mandarin is a contraction of 不要 (bùyào), and 覅 (fiào) 'don't' in Shanghainese is a contraction of 勿要 (wù yào), as

7085-544: The clumsily long name "quasi-stellar radio sources" is used to describe these objects. Because the nature of these objects is entirely unknown, it is hard to prepare a short, appropriate nomenclature for them so that their essential properties are obvious from their name. For convenience, the abbreviated form "quasar" will be used throughout this paper. Between 1917 and 1922, it became clear from work by Heber Doust Curtis , Ernst Öpik and others that some objects (" nebulae ") seen by astronomers were in fact distant galaxies like

7194-421: The contraction of cela (demonstrative pronoun "that") to ça is optional and informal. In informal speech, a personal pronoun may sometimes be contracted onto a following verb . For example, je ne sais pas ( IPA: [ʒənəsɛpa] , "I don't know") may be pronounced roughly chais pas ( IPA: [ʃɛpa] ), with the ne being completely elided and the [ʒ] of je being mixed with

7303-519: The definite articles o and a (masculine and feminine forms of "the" respectively), producing do , da (of the), pelo , pela (by the). The preposition de contracts with the pronouns ele and ela (he, she), producing dele , dela (his, her). In addition, some verb forms contract with enclitic object pronouns: e.g., the verb amar (to love) combines with the pronoun a (her), giving amá-la (to love her). Another contraction in Portuguese that

7412-645: The distance light could travel in the universe's 13.8-billion-year history because the universe is expanding). It is now understood that many quasars are triggered by the collisions of galaxies, which drives the mass of the galaxies into the supermassive black holes at their centers. More than 900,000 quasars have been found (as of July 2023), most from the Sloan Digital Sky Survey . All observed quasar spectra have redshifts between 0.056 and 10.1 (as of 2024), which means they range between 600 million and 30 billion light-years away from Earth . Because of

7521-566: The distant past; the peak epoch was approximately 10 billion years ago. Concentrations of multiple quasars are known as large quasar groups and may constitute some of the largest known structures in the universe if the observed groups are good tracers of mass distribution. The term quasar was first used in an article by astrophysicist Hong-Yee Chiu in May 1964, in Physics Today , to describe certain astronomically puzzling objects: So far,

7630-407: The entire observable electromagnetic spectrum , including radio , infrared , visible light , ultraviolet , X-ray and even gamma rays . Most quasars are brightest in their rest-frame ultraviolet wavelength of 121.6  nm Lyman-alpha emission line of hydrogen, but due to the tremendous redshifts of these sources, that peak luminosity has been observed as far to the red as 900.0 nm, in

7739-455: The exception of 3C 273 , whose average apparent magnitude is 12.9, cannot be seen with small telescopes. Quasars are believed—and in many cases confirmed—to be powered by accretion of material into supermassive black holes in the nuclei of distant galaxies, as suggested in 1964 by Edwin Salpeter and Yakov Zeldovich . Light and other radiation cannot escape from within the event horizon of

7848-444: The far infrared with a peak in the ultraviolet optical bands, with some quasars also being strong sources of radio emission and of gamma-rays. With high-resolution imaging from ground-based telescopes and the Hubble Space Telescope , the "host galaxies" surrounding the quasars have been detected in some cases. These galaxies are normally too dim to be seen against the glare of the quasar, except with special techniques. Most quasars, with

7957-480: The first time with images of the double quasar 0957+561. A study published in February 2021 showed that there are more quasars in one direction (towards Hydra ) than in the opposite direction, seemingly indicating that the Earth is moving in that direction. But the direction of this dipole is about 28° away from the direction of the Earth's motion relative to the cosmic microwave background radiation. In March 2021,

8066-416: The gas to fall into the supermassive black holes, releasing enormous radiant energies. These black holes co-evolve with the mass of stars in their host galaxy in a way not fully understood at present. One idea is that jets, radiation and winds created by the quasars shut down the formation of new stars in the host galaxy, a process called "feedback". The jets that produce strong radio emission in some quasars at

8175-557: The great distances to the farthest quasars and the finite velocity of light, they and their surrounding space appear as they existed in the very early universe. The power of quasars originates from supermassive black holes that are believed to exist at the core of most galaxies. The Doppler shifts of stars near the cores of galaxies indicate that they are revolving around tremendous masses with very steep gravity gradients, suggesting black holes. Although quasars appear faint when viewed from Earth, they are visible from extreme distances, being

8284-405: The host galaxy. About a million quasars have been identified with reliable spectroscopic redshifts, and between 2-3 million identified in photometric catalogs. The nearest known quasar is about 600 million light-years from Earth, while the record for the most distant known quasar is 31.7 billion light-years away. Quasar discovery surveys have shown that quasar activity was more common in

8393-617: The many dialects of Norwegian and their widespread use it is often difficult to distinguish between non-standard writing of standard Norwegian and eye dialect spelling. It is almost universally true that these spellings try to convey the way each word is pronounced, but it is rare to see language written that does not adhere to at least some of the rules of the official orthography . Reasons for this include words spelled unphonemically, ignorance of conventional spelling rules, or adaptation for better transcription of that dialect's phonemes. Latin contains several examples of contractions. One such case

8502-534: The most luminous objects in the known universe. The brightest quasar in the sky is 3C 273 in the constellation of Virgo . It has an average apparent magnitude of 12.8 (bright enough to be seen through a medium-size amateur telescope ), but it has an absolute magnitude of −26.7. From a distance of about 33 light-years, this object would shine in the sky about as brightly as the Sun . This quasar's luminosity is, therefore, about 4 trillion (4 × 10) times that of

8611-422: The near infrared. A minority of quasars show strong radio emission, which is generated by jets of matter moving close to the speed of light. When viewed downward, these appear as blazars and often have regions that seem to move away from the center faster than the speed of light ( superluminal expansion). This is an optical illusion due to the properties of special relativity . Quasar redshifts are measured from

8720-614: The now-standard form "o'clock"). The main contractions are listed in the following table. Although can't , wouldn't and other forms ending ‑n't clearly started as contractions, ‑n't is now neither a contraction (a cliticized form) nor part of one but instead a negative inflectional suffix. Evidence for this is (i) ‑n't occurs only with auxiliary verbs , and clitics are not limited to particular categories or subcategories; (ii) again unlike contractions, their forms are not rule-governed but idiosyncratic (e.g., will → won't, can → can't ); and (iii) as shown in

8829-543: The object position. In fact, 于/於 '(is) in; at', 曰 'say', and 如 'resemble' are never followed by 之 '(third-person object)' or 此 '(near demonstrative)' in pre- Qin texts. Instead, the respective 'contractions' 爰/焉, 云, and 然 are always used in their place. Nevertheless, no known object pronoun is phonologically appropriate to serve as the hypothetical pronoun that underwent contraction. Hence, many authorities do not consider them to be true contractions. As an alternative explanation for their origin, Edwin G. Pulleyblank proposed that

8938-547: The object “3C 48” consists of two significant parts. The first part, “3C,” means that the object belongs to the Third Cambridge Catalog of Radio Sources . The second part - “48” - is the serial number in the catalog ordered by right ascension . 3C 48 was the first source in the Third Cambridge Catalog of Radio Sources to be optically identified by Allan Sandage and Thomas Matthews in 1960 using interferometry. Jesse Greenstein and Thomas Matthews found that it had

9047-612: The observations and redshifts themselves were not doubted, their correct interpretation was heavily debated, and Bolton's suggestion that the radiation detected from quasars were ordinary spectral lines from distant highly redshifted sources with extreme velocity was not widely accepted at the time. An extreme redshift could imply great distance and velocity but could also be due to extreme mass or perhaps some other unknown laws of nature. Extreme velocity and distance would also imply immense power output, which lacked explanation. The small sizes were confirmed by interferometry and by observing

9156-533: The observed power and fit within a deep gravitational well. There were also serious concerns regarding the idea of cosmologically distant quasars. One strong argument against them was that they implied energies that were far in excess of known energy conversion processes, including nuclear fusion . There were suggestions that quasars were made of some hitherto unknown stable form of antimatter in similarly unknown types of region of space, and that this might account for their brightness. Others speculated that quasars were

9265-442: The particle の ( no ) is contracted to simply ん ( n ). When used after verbs ending in the conjunctive form ～て ( -te ), certain auxiliary verbs and their derivations are often abbreviated. Examples: * this abbreviation is never used in the polite conjugation, to avoid the resultant ambiguity between an abbreviated ikimasu (go) and the verb kimasu (come). The ending ～なければ ( -nakereba ) can be contracted to ～なきゃ ( -nakya ) when it

9374-460: The preposition and the article ; for example, von dem becomes vom , zu dem becomes zum , or an das becomes ans . Some of these are so common that they are mandatory. In informal speech, aufm for auf dem , unterm for unter dem , etc. are also used, but would be considered to be incorrect if written, except maybe in quoted direct speech, in appropriate context and style. The pronoun es often contracts to ' s (usually written with

9483-417: The primary source of reionization; the primary causes of reionization were probably the earliest generations of stars , known as Population III stars (possibly 70%), and dwarf galaxies (very early small high-energy galaxies) (possibly 30%). Quasars show evidence of elements heavier than helium , indicating that galaxies underwent a massive phase of star formation , creating population III stars between

9592-404: The quasar becomes a more ordinary type of galaxy. The accretion-disc energy-production mechanism was finally modeled in the 1970s, and black holes were also directly detected (including evidence showing that supermassive black holes could be found at the centers of this and many other galaxies), which resolved the concern that quasars were too luminous to be a result of very distant objects or that

9701-485: The radio-emitting electrons in the jet. Iron quasars show strong emission lines resulting from low-ionization iron (Fe  II ), such as IRAS 18508-7815. Quasars also provide some clues as to the end of the Big Bang 's reionization . The oldest known quasars ( z  = 6) display a Gunn–Peterson trough and have absorption regions in front of them indicating that the intergalactic medium at that time

9810-405: The same meaning.) The Munich-born footballer Franz Beckenbauer has as his catchphrase "Schau mer mal" ("Schauen wir einmal" - in English "We shall see."). A book about his career had as its title the slightly longer version of the phrase, "Schau'n Mer Mal". Such features are found in all central and southern language regions. A sample from Berlin: Sag einmal, Meister, kann man hier einmal hinein?

9919-463: The same physical location is very low, and determining whether the system is closely separated physically requires significant observational effort. The first true triple quasar was found in 2007 by observations at the W. M. Keck Observatory in Mauna Kea , Hawaii . LBQS 1429-008 (or QQQ J1432-0106) was first observed in 1989 and at the time was found to be a double quasar. When astronomers discovered

10028-403: The same strange emission lines. Schmidt was able to demonstrate that these were likely to be the ordinary spectral lines of hydrogen redshifted by 15.8%, at the time, a high redshift (with only a handful of much fainter galaxies known with higher redshift). If this was due to the physical motion of the "star", then 3C 273 was receding at an enormous velocity, around 47 000  km/s , far beyond

10137-430: The sky containing one such source, 3C48, with the 200-inch telescope. To their surprise, there were no objects within the error rectangle of the coordinates in this area except for a star of 16.2 . True, there were traces of a faint small nebula around it, but the object certainly looked like a star. Doubts about the possibility of identifying the radio source with a star disappeared on October 22, 1960, when Sandage obtained

10246-457: The speed of any known star and defying any obvious explanation. Nor would an extreme velocity help to explain 3C 273's huge radio emissions. If the redshift was cosmological (now known to be correct), the large distance implied that 3C 273 was far more luminous than any galaxy, but much more compact. Also, 3C 273 was bright enough to detect on archival photographs dating back to the 1900s; it was found to be variable on yearly timescales, implying that

10355-518: The speed with which the quasar as a whole varied in output, and by their inability to be seen in even the most powerful visible-light telescopes as anything more than faint starlike points of light. But if they were small and far away in space, their power output would have to be immense and difficult to explain. Equally, if they were very small and much closer to this galaxy, it would be easy to explain their apparent power output, but less easy to explain their redshifts and lack of detectable movement against

10464-466: The strong spectral lines that dominate their visible and ultraviolet emission spectra. These lines are brighter than the continuous spectrum. They exhibit Doppler broadening corresponding to mean speed of several percent of the speed of light. Fast motions strongly indicate a large mass. Emission lines of hydrogen (mainly of the Lyman series and Balmer series ), helium, carbon, magnesium, iron and oxygen are

10573-725: The table, the inflected and "uncontracted" versions may require different positions in a sentence. The Old Chinese writing system ( oracle bone script and bronzeware script ) is well suited for the (almost) one-to-one correspondence between morpheme and glyph . Contractions in which one glyph represents two or more morphemes are a notable exception to that rule. About 20 or so are noted to exist by traditional philologists and are known as jiāncí (兼詞, lit. 'concurrent words'), and more words have been proposed to be contractions by recent scholars , based on recent reconstructions of Old Chinese phonology, epigraphic evidence, and syntactic considerations. For example, 非 [fēi] has been proposed to be

10682-438: The term "abbreviation" in layman’s terms. Contraction is also distinguished from morphological clipping , where beginnings and endings are omitted. The definition overlaps with the term portmanteau (a linguistic blend ), but a distinction can be made between a portmanteau and a contraction by noting that contractions are formed from words that would otherwise appear together in sequence, such as do and not , whereas

10791-413: The third member, they confirmed that the sources were separate and not the result of gravitational lensing. This triple quasar has a redshift of z = 2.076. The components are separated by an estimated 30–50  kiloparsecs (roughly 97,000–160,000 light-years), which is typical for interacting galaxies. In 2013, the second true triplet of quasars, QQQ J1519+0627, was found with a redshift z = 1.51,

10900-459: The time of the Big Bang and the first observed quasars. Light from these stars may have been observed in 2005 using NASA 's Spitzer Space Telescope , although this observation remains to be confirmed. The taxonomy of quasars includes various subtypes representing subsets of the quasar population having distinct properties. Because quasars are extremely distant, bright, and small in apparent size, they are useful reference points in establishing

11009-408: The universe does not appear to have had large amounts of antimatter at the relevant times.) Since quasars exhibit all the properties common to other active galaxies such as Seyfert galaxies , the emission from quasars can be readily compared to those of smaller active galaxies powered by smaller supermassive black holes. To create a luminosity of 10  watts (the typical brightness of a quasar),

11118-477: The various forms of the definite article , namely il , lo , la , l', i , gli , gl', and le . The words ci and è (form of essere , to be) and the words vi and è are contracted into c'è and v'è (both meaning "there is"). The words dove and come are contracted with any word that begins with e , deleting the -e of the principal word, as in "Com'era bello!" – "How handsome he / it was!", "Dov'è il tuo amico?" – "Where's your friend?" The same

11227-717: The whole system fitting within a physical separation of 25 kpc (about 80,000 light-years). The first true quadruple quasar system was discovered in 2015 at a redshift z  = 2.0412 and has an overall physical scale of about 200 kpc (roughly 650,000 light-years). Contraction (grammar) A contraction is a shortened version of the spoken and written forms of a word , syllable , or word group , created by omission of internal letters and sounds. In linguistic analysis , contractions should not be confused with crasis , abbreviations and initialisms (including acronyms ), with which they share some semantic and phonetic functions, though all three are connoted by

11336-460: The word y or en . It is also mandatory to avoid the repetition of a sound when the conjunction si ("if") is followed by il ("he", "it") or ils ("they"), which begin with the same vowel sound i : *si il → s'il ("if it", if he"); *si ils → s'ils ("if they"). Certain prepositions are also mandatorily merged with masculine and plural direct articles: au for à le , aux for à les , du for de le , and des for de les . However,

11445-557: Was neutral gas . More recent quasars show no absorption region, but rather their spectra contain a spiky area known as the Lyman-alpha forest ; this indicates that the intergalactic medium has undergone reionization into plasma , and that neutral gas exists only in small clouds. The intense production of ionizing ultraviolet radiation is also significant, as it would provide a mechanism for reionization to occur as galaxies form. Despite this, current theories suggest that quasars were not

11554-427: Was early strong evidence against steady-state cosmology and in favor of the Big Bang cosmology. Quasars show the locations where supermassive black holes are growing rapidly (by accretion ). Detailed simulations reported in 2021 showed that galaxy structures, such as spiral arms, use gravitational forces to 'put the brakes on' gas that would otherwise orbit galaxy centers forever; instead the braking mechanism enabled

11663-514: Was not due to the expansion of space but rather to light escaping a deep gravitational well . This would require a massive object, which would also explain the high luminosities. However, a star of sufficient mass to produce the measured redshift would be unstable and in excess of the Hayashi limit . Quasars also show forbidden spectral emission lines, previously only seen in hot gaseous nebulae of low density, which would be too diffuse to both generate

11772-594: Was not until 1982 that the surrounding faint galactic "nebulosity" was confirmed to have the same redshift as 3C48, cementing its identification as an object in a distant galaxy. This was also the first solid identification of a quasar with a surrounding galaxy at the same redshift. 3C 48 is one of four primary calibrators used by the Very Large Array (along with 3C 138 and 3C 147 , and 3C 286 ). Visibilities of all other sources are calibrated using observed visibilities of one of these four calibrators. The name of

11881-411: Was the second source conclusively identified as such. 3C48 was the first source in the Third Cambridge Catalogue of Radio Sources for which an optical identification was found by Allan Sandage and Thomas A. Matthews in 1960 through interferometry . In 1963 Jesse L. Greenstein and Thomas Matthews found that it had a redshift of 0.367, making it one of the highest redshift sources then known. It

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