| 释义 |
magnitude
mag·ni·tude M0035500 (măg′nĭ-to͞od′, -tyo͞od′)n.1. a. Greatness of rank or position: "such duties as were expected of a landowner of his magnitude" (Anthony Powell).b. Greatness in size or extent: The magnitude of the flood was impossible to comprehend.c. Greatness in significance or influence: was shocked by the magnitude of the crisis.2. Astronomy a. The brightness of a celestial body on a numerical scale for which brighter objects have smaller values. Differences in magnitude are based on a logarithmic scale that matches the response of the human eye to differences in brightness so that a decrease of one magnitude represents an increase in apparent brightness by a factor of 2.512. Also called apparent magnitude.b. A unit on such a scale of brightness.3. Mathematics a. A number assigned to a quantity so that it may be compared with other quantities.b. A property that can be described by a real number, such as the volume of a sphere or the length of a vector.4. Geology A measure of the amount of energy released by an earthquake, as indicated on the Richter scale.
[Middle English, from Old French, size, from Latin magnitūdō, greatness, size, from magnus, great; see meg- in Indo-European roots.]magnitude (ˈmæɡnɪˌtjuːd) n1. relative importance or significance: a problem of the first magnitude. 2. relative size or extent: the magnitude of the explosion. 3. (Mathematics) maths a number assigned to a quantity, such as weight, and used as a basis of comparison for the measurement of similar quantities4. (Astronomy) astronomy Also called: apparent magnitude the apparent brightness of a celestial body expressed on a numerical scale on which bright stars have a low value. Values are measured by eye (visual magnitude) or more accurately by photometric or photographic methods, and range from –26.7 (the sun), through 1.5 (Sirius), down to about +30. Each integral value represents a brightness 2.512 times greater than the next highest integral value. See also absolute magnitude, visual magnitude5. (Geological Science) geology Also called: earthquake magnitude a measure of the size of an earthquake based on the quantity of energy released: specified on the Richter scale. See Richter scale[C14: from Latin magnitūdō size, from magnus great] ˌmagniˈtudinous adjmag•ni•tude (ˈmæg nɪˌtud, -ˌtyud)
n. 1. size; extent; dimensions. 2. great importance or consequence: affairs of magnitude. 3. greatness of size or amount. 4. a. the brightness of a celestial body as expressed on a logarithmic scale where an increase of 1 equals a reduction in brightness by a factor of 2.512, the sixth magnitude being the dimmest observable with the naked eye. b. absolute magnitude. 5. a number characteristic of a quantity and forming a basis for comparison with similar quantities, as length. Idioms: of the first magnitude, of greatest significance. [1350–1400; Middle English < Latin magnitūdō, derivative, with -tūdō -tude, of magnus large, greatmeg-] mag·ni·tude (măg′nĭ-to͞od′)1. The brightness of a star or another celestial body as seen from the Earth, measured on a numerical scale in which lower numbers mean greater brightness. The dimmest stars visible to the unaided eye have magnitude 6, while the brightest star outside our solar system, Sirius, has magnitude -1.4. The moon has magnitude -12.7, and the sun has magnitude -26.8.2. A measure of the total amount of energy released by an earthquake, as indicated on the Richter scale.magnitudeA star’s brightness measured as either absolute magnitude or apparent magnitude. The latter states brightness in the sky on a scale from -26.8 (the Sun, brightest) to +25 (the faintest).Thesaurus| Noun | 1. | magnitude - the property of relative size or extent (whether large or small); "they tried to predict the magnitude of the explosion"; "about the magnitude of a small pea"property - a basic or essential attribute shared by all members of a class; "a study of the physical properties of atomic particles"absolute magnitude - (astronomy) the magnitude that a star would have if it were viewed from a distance of 10 parsecs (32.62 light years) from the earthproportion, dimension - magnitude or extent; "a building of vast proportions"order of magnitude, order - a degree in a continuum of size or quantity; "it was on the order of a mile"; "an explosion of a low order of magnitude"dimension - the magnitude of something in a particular direction (especially length or width or height)degree - the seriousness of something (e.g., a burn or crime); "murder in the second degree"; "a second degree burn"amplitude - greatness of magnitudemultiplicity - the property of being multipletriplicity - the property of being triplesize - the physical magnitude of something (how big it is); "a wolf is about the size of a large dog"size - a large magnitude; "he blanched when he saw the size of the bill"; "the only city of any size in that area"bulk, volume, mass - the property of something that is great in magnitude; "it is cheaper to buy it in bulk"; "he received a mass of correspondence"; "the volume of exports"muchness - greatness of quantity or measure or extentintensity, intensity level, strength - the amount of energy transmitted (as by acoustic or electromagnetic radiation); "he adjusted the intensity of the sound"; "they measured the station's signal strength"amount - the relative magnitude of something with reference to a criterion; "an adequate amount of food for four people"extent - the distance or area or volume over which something extends; "the vast extent of the desert"; "an orchard of considerable extent" | | 2. |  magnitude - a number assigned to the ratio of two quantities; two quantities are of the same order of magnitude if one is less than 10 times as large as the other; the number of magnitudes that the quantities differ is specified to within a power of 10order of magnituderatio - the relative magnitudes of two quantities (usually expressed as a quotient) | | 3. |  magnitude - relative importance; "a problem of the first magnitude"extensiveness, largeness - large or extensive in breadth or importance or comprehensiveness; "the might have repercussions of unimaginable largeness"; "the very extensiveness of his power was a temptation to abuse it"importance - the quality of being important and worthy of note; "the importance of a well-balanced diet" |
magnitudenoun1. importance, consequence, significance, mark, moment, note, weight, proportion, dimension, greatness, grandeur, eminence An operation of this magnitude is going to be difficult.
importance insignificance, triviality, unimportance2. immensity, size, extent, enormity, strength, volume, vastness, bigness, largeness, hugeness the magnitude of the task confronting them
immensity meanness, smallness3. intensity, measure, capacity, amplitude a quake with a magnitude exceeding 5magnitudenoun1. Great extent, amount, or dimension:amplitude, bulk, mass, size, volume (often used in plural).2. The quality or state of being large in amount, extent, or importance:amplitude, bigness, greatness, largeness, sizableness, size.3. Relative intensity or amount, as of a quality or attribute:degree, extent, measure, proportion.4. The amount of space occupied by something:dimension, extent, measure, proportion (often used in plural), size.Translationsmagnitude (ˈmӕgnitjuːd) noun1. importance. a decision of great magnitude. 重要性 重要性2. size. a star of great magnitude. 大小 大小magnitude
of the first magnitudeOf major importance or significance. You have to study Shakespeare because he is a poet of the first magnitude. We need to close the highway immediately—this is an accident of the first magnitude.See also: first, magnitude, ofof the highest magnitudeOf the greatest importance or significance or to the greatest degree or extent. You have to study Shakespeare because he is a poet of the highest magnitude. We need to close the highway immediately—this is an emergency of the highest magnitude.See also: high, magnitude, offirst magnitude/order/water, of theThe best; of the highest quality. Magnitude refers to the grading of the brightness of stars, the first being the brightest. It has been transferred to other matters since at least the seventeenth century. “Thou liar of the first magnitude,” wrote William Congreve in 1695 (Love for Love, 2.2). Water refers to a system for grading diamonds for their color or luster (the latter being akin to the shininess of water), the best quality again being termed the first. This grading system is no longer used, but the transfer to other matters has survived since the early nineteenth century. Sir Walter Scott’s journal has, “He was a . . . swindler of the first water (1826). Order, which here refers to rank, is probably more often heard today than either of the others. It dates from the nineteenth century. The OED cites “A diplomatist of the first order,” appearing in a journal of 1895. A synonymous term, first rate, originated from the time the Royal Navy’s warships were rated on a scale of one to six, based on their size and the weight of the weapons they carried. By the 1700s this term, along with second-rate, third-rate, and so on, was later transferred to general use, most often as a hyphenated adjective. For example, “He’s definitely a second-rate poet, nowhere near as good as his father.”See also: first, magnitude, of, ordermagnitude
magnitude, in astronomy, measure of the brightness of a star or other celestial object. The stars cataloged by Ptolemy (2d cent. A.D.), all visible with the unaided eye, were ranked on a brightness scale such that the brightest stars were of 1st magnitude and the dimmest stars were of 6th magnitude. The modern magnitude scale was placed on a precise basis by N. R. Pogson (1856). It was found by photometric measurements that stars of the 1st magnitude were about 100 times as bright as stars of the 6th magnitude, i.e., 5 magnitudes lower. Pogson defined a difference of 5 magnitudes to be exactly equal to a hundredfold change in brightness, so that stars differing by 1 magnitude differ in brightness by a factor of 2.512 (the 5th root of 100). The modern magnitude scale permits a precise expression of a star's relative brightness and extends to both extremely bright and very dim objects. Thus, an object 2.512 times as bright as a 1st-magnitude star is of 0 magnitude; brighter objects have negative magnitudes. The sun's magnitude, for example, is −26.8. On the other hand, a faint star of 16th magnitude is only 1/10,000 as bright as a 6th-magnitude star, the dimmest that can be seen with the naked eye. Magnitudes determined on the basis of an object's relative brightness as seen from the earth are known as apparent magnitudes. Astronomers also assign a star an absolute magnitude, which is the magnitude that a star would have if it were located at a standard distance of 10 parsecsparsec
[parallax + second], in astronomy, basic unit of length for measuring interstellar and intergalactic distances, equal to 206,265 times the distance from the earth to the sun, 3.26 light-years, or 3.08 × 1013 km (about 19 million million mi).
..... Click the link for more information. (32.6 light-years). Absolute magnitude is a measure of the intrinsic luminosityluminosity,
in astronomy, the rate at which energy of all types is radiated by an object in all directions. A star's luminosity depends on its size and its temperature, varying as the square of the radius and the fourth power of the absolute surface temperature.
..... Click the link for more information. of the star, i.e., its true brightness. Since in modern times magnitudes are measured with photometers and electronic detectors, which may be more sensitive to light at one wavelength than at another wavelength, it is necessary to specify the method and the filter used when comparing two or more magnitudes. The magnitude usually referred to is the visual, or photovisual, magnitude, measured with a photometer. Pogson Scale of Magnitudes magnitude (mag -nă-tewd) A measure of the brightness of stars and other celestial objects. The brighter the object the lower its assigned magnitude. Expressions of magnitude are used primarily in the visible, near-infrared, and near-ultraviolet regions of the spectrum. The apparent magnitude, symbol: m , is a measure of the brightness of a star, etc., as observed from Earth. Its value depends on the star's luminosity (i.e. its intrinsic brightness), its distance, and the amount of light absorption by interstellar matter between the star and Earth. In ancient times the visible stars were ranked in six classes of apparent magnitude: the brightest stars were of first magnitude and those just visible to the naked eye were of sixth magnitude. This system became inadequate as fainter stars were discovered with the telescope and instruments became available for measuring apparent brightness. In the 1850s it was proposed that the physiological response of the eye to a physical stimulus was proportional to the logarithm of that stimulus (Weber-Fechner law). A difference in apparent magnitude of two stars is thus proportional to the difference in the logarithms of their brightness, i.e. to the logarithm of the ratio of their brightness. In order to make the magnitude scale precise the English astronomer N.R. Pogson proposed, in 1856, that a difference of five magnitudes should correspond exactly to a brightness ratio of 100 to 1. (W. Herschel had shown this to be approximately true.) Hence two stars that differ by one magnitude have a brightness ratio of 1001/5:1, i.e. a ratio – known as the Pogson ratio – of 2.512. A star two magnitudes less than another is (2.512)2, i.e. 6.3 times, brighter, and so on. In general the apparent magnitudes m 1 and m 2 of two stars with apparent brightness I 1 and I 2 are related by: m 1 – m 2 = 2.5 log10 (I 2 /I 1 ) The Pogson scale, based on the Pogson ratio, is now the universally adopted scale of magnitude (see table). The zero of the scale was established by assigning magnitudes to a group of standard stars near the north celestial pole, known as the North Polar Sequence, or more recently by photoelectric measurements. The class of magnitude-one stars was found to contain too great a range of brightness and zero and negative magnitudes were consequently introduced: the higher the negative number, the greater the brightness. The scale also had to be extended in the positive direction as fainter objects were discovered. Values can be recorded in tenths, hundredths, even thousandths of a magnitude. Originally apparent magnitude was measured by eye – visual magnitude, m vis – usually in conjunction with an instrument by which brightnesses could be compared. It is now measured much more accurately by photometric techniques but previous to that photographic methods were used. Photographic magnitudes, m pg, are determined from the optical density of images on ordinary film, i.e. film that has a maximum response to blue light. Photo?-visual magnitudes, m pv, are measured using film that has been sensitized to light – yellowish green in color – to which the human eye is most sensitive. In the early International Color System these two magnitudes were measured with films having a maximum response to a wavelength of 425 nanometers (m pg) and 570 nm (m pv ), the magnitudes being equal for A0 stars. A suitable combination of photometer and filter can select light or other radiation of a desired wavelength band and measure its intensity. These photoelectric magnitudes can be measured over either narrow or broad bands. The UBV system of stellar magnitudes is based on photoelectric photometry and has been widely adopted as the successor of the International System. The photoelectric magnitudes, denoted U , B , and V are measured at three broad bands: U (ultraviolet radiation) centered on a wavelength of 365 nm, B (blue) centered on 440 nm, and V (visual, i.e. yellowish green) centered on 550 nm. These magnitudes can also be written m U, m B, and m V. The zero point of the UBV system is defined in terms of standard stars having a carefully studied and agreed magnitude. Another important photometric system, the uvby system, uses filters passing narrower wavelength bands than in the UVB system. The UBV system has been extended by the use of magnitudes at red and infrared wavelengths. The photometric designations are R (700 nm, i.e. 0.7 μm), I (0.9 μm), J (1.25 μm), H (1.6 μm), K (2.20 μm), L (3.40 μm), M (5.0 μm), N (10.2 μm), Q (21 μm). The designations J –Q relate to the infrared atmospheric windows; two alternative values for R (640 nm) and I (800 nm) have recently gained acceptance. Apparent magnitude is a measure of the radiation in a particular wavelength band, say of blue light, received from the celestial body. Apparent bolometric magnitude, m bol, is a measure of the total radiation received from the body. The bolometric correction (BC) is the difference m V – m bol between the apparent visual (V) and bolometric magnitudes; it is generally defined to be zero for stars with surface temperatures similar to the Sun. Other wavebands apart from V are sometimes used in calculating BC. Apparent magnitude gives no indication of a body's luminosity: a very distant very luminous star may have a similar apparent magnitude as a closer but fainter star. Luminosity is defined in terms of absolute magnitude, M , which is the apparent magnitude of a body if it were at a standard distance of 10 parsecs. It can be shown that the two magnitudes of a body are related to distance d (in parsecs) or its annual parallax, π (in arc seconds): M = m + 5 – 5 logd – A M = m + 5 + 5 logπ – A A is the interstellar extinction. As with apparent magnitude there are values of absolute photoelectric magnitudes: M U , M B, M V, etc.; of bolometric magnitude: M bol; and of photographic magnitudes: M pg and M pv. Knowledge of a body's absolute bolometric magnitude enables its luminosity to be found. The flux density in jansky of a body can be determined from a value of absolute magnitude at one of the photometric designations J–Q. magnitude[′mag·nə‚tüd] (astronomy) The relative luminance of a celestial body; the smaller (algebraically) the number indicating magnitude, the more luminous the body. Also known as stellar magnitude. (geophysics) A measure of the amount of energy released by an earthquake. (mathematics) absolute value magnitude1. Maths a number assigned to a quantity, such as weight, and used as a basis of comparison for the measurement of similar quantities 2. Astronomy the apparent brightness of a celestial body expressed on a numerical scale on which bright stars have a low value. Values are measured by eye (visual magnitude) or more accurately by photometric or photographic methods, and range from --26.7 (the sun), through 1.5 (Sirius), down to about +30. Each integral value represents a brightness 2.512 times greater than the next highest integral value 3. Geology a measure of the size of an earthquake based on the quantity of energy released: specified on the Richter scale magnitude
mag·ni·tude (mag'ni-tūd), Size or extent.AcronymsSeeMmagnitude
Synonyms for magnitudenoun importanceSynonyms- importance
- consequence
- significance
- mark
- moment
- note
- weight
- proportion
- dimension
- greatness
- grandeur
- eminence
Antonyms- insignificance
- triviality
- unimportance
noun immensitySynonyms- immensity
- size
- extent
- enormity
- strength
- volume
- vastness
- bigness
- largeness
- hugeness
Antonymsnoun intensitySynonyms- intensity
- measure
- capacity
- amplitude
Synonyms for magnitudenoun great extent, amount, or dimensionSynonyms- amplitude
- bulk
- mass
- size
- volume
noun the quality or state of being large in amount, extent, or importanceSynonyms- amplitude
- bigness
- greatness
- largeness
- sizableness
- size
noun relative intensity or amount, as of a quality or attributeSynonyms- degree
- extent
- measure
- proportion
noun the amount of space occupied by somethingSynonyms- dimension
- extent
- measure
- proportion
- size
Synonyms for magnitudenoun the property of relative size or extent (whether large or small)Related Words- property
- absolute magnitude
- proportion
- dimension
- order of magnitude
- order
- degree
- amplitude
- multiplicity
- triplicity
- size
- bulk
- volume
- mass
- muchness
- intensity
- intensity level
- strength
- amount
- extent
noun a number assigned to the ratio of two quantitiesSynonymsRelated Wordsnoun relative importanceRelated Words- extensiveness
- largeness
- importance
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