| 单词 | variable star |
| 例句 | To test the distance of the spiral nebulae, a class of intrinsically much brighter variable stars was needed to furnish a new standard candle. Cosmos 1980-01-01T00:00:00Z The cyclical dimming and brightening of variable stars fascinated Henrietta Leavitt, who became the first person to realise that the frequency of their pulsation was directly related to their brightness. Looking at the stars 2016-12-20T05:00:00Z Edwin Hubble leveraged Leavitt’s law on the behavior of variable stars to gauge distances to certain nebulae. Ladies Who Launch: Women Who Opened the Door to Space Exploration 2016-12-26T05:00:00Z A key rung relies on observations of variable stars called Cepheids. The universe’s puzzlingly fast expansion may defy explanation, cosmologists fret 2023-10-31T04:00:00Z The approaches include looking at supernovae and variable stars in distant galaxies and measuring how fast they’re receding, as well as how far away they are. Will the Universe Ever Stop Expanding? 2023-08-29T04:00:00Z Much of their work was on variable stars. This Astronomer Discovered What the Stars Were Made Of, And Few Believed Her Discovery 2023-06-22T04:00:00Z He was also able to show that cepheid variable stars are not binary systems, as some people thought at the time, but individual stars that pulsate with striking regularity. Astronomy 2016-10-13T00:00:00Z “Betelgeuse is a variable star. It changes with time..., and Antares is variable as well, but we don’t know the cycles as well,” Kafka says. Ancient Stargazers Saw Betelgeuse Shine a Different Color 2022-08-18T04:00:00Z In general, luminous blue variable stars are known to experience giant outbursts of matter throughout their life. The mystery of the massive star that disappeared without a trace 2020-07-02T04:00:00Z Experts discovered a surprising “super-outburst” from a dwarf nova, a type of “cataclysmic variable star.” 'Vampire' star spotted by NASA’s planet-hunting Kepler space telescope 2020-01-27T05:00:00Z She used a relationship between the luminosities and periodicities of variable stars to measure distances to galaxies. Vera Rubin Gets a Telescope of Her Own 2020-01-11T05:00:00Z In 1994, using the Hubble Space Telescope, astronomers were able to make out an individual cepheid variable star in the galaxy M100 and measure its distance to be 56 million light-years. Astronomy 2016-10-13T00:00:00Z Betelgeuse, a variable star that is normally one of the brightest stars in the sky, is currently at its faintest level ever seen. Daily briefing: Origin of repeating fast radio burst deepens its mystery 2020-01-09T05:00:00Z The red supergiant is a variable star that brightens and fades unpredictably, but after weeks of dimming, it’s currently at its faintest level so far. Daily briefing: Betelgeuse is going dim, exciting astronomers 2020-01-05T05:00:00Z The Polish results support an analysis of Cepheid variable stars published in February in Nature Astronomy journal by astronomers from Macquarie University in Australia and the Chinese Academy of Sciences. We live in a warped and twisted galaxy 2019-08-01T04:00:00Z One method uses objects of known brightness, called standard candles, such as Cepheid variable stars. The Universe's Fate Rests on the Hubble Constant--Which Has So Far Eluded Astronomers 2019-01-30T05:00:00Z These systems presented a wonderful opportunity to study the behavior of variable stars independent of their distance. Astronomy 2016-10-13T00:00:00Z For the local universe, these mile markers are Cepheid variable stars, which periodically pulse and share the same intrinsic brightness. How 1.7 Billion Stars Were Mapped With Dazzling 3-D Precision 2018-04-25T04:00:00Z Cecilia Payne-Gaposchkin was an innovative astronomer whose career included studies of stellar composition, the structure of the Milky Way, and the study of more than 3 million variable stars. Women in Science are a Force of Nature 2018-03-08T05:00:00Z “People forget,” Christian said, “but the sun is a variable star.” This NASA spacecraft will get closer to the sun than anything ever before 2018-01-22T05:00:00Z Cecilia Payne-Gaposchkin was an innovative astronomer whose career included studies of stellar composition, the structure of the Milky Way, and the study of more than 3 million variable stars. Women in Science are a Force of Nature 2017-12-13T05:00:00Z If all the variable stars in the Magellanic Clouds are at roughly the same distance, then any difference in their apparent brightnesses must be caused by differences in their intrinsic luminosities. Astronomy 2016-10-13T00:00:00Z It was like, ‘Junk, junk, variable star — ooh, planet!’ NASA finds evidence of 10 new Earth-sized planets in our corner of the galaxy 2017-06-19T04:00:00Z The first rung seemed reasonably sturdy: variable stars called cepheids, which ramp up and down in brightness over the course of days or weeks. A recharged debate over the speed of the expansion of the universe could lead to new physics 2017-03-08T05:00:00Z Pickering was especially interested in variable stars, whose light would brighten and fade over a specific period. History: Women who read the stars : Nature : Nature Research 2016-11-22T05:00:00Z The astronomers were looking for variable stars call Cepheids, which pulse at a rate related to their brightness. Astronomers find disk of young stars near center of Milky Way 2015-10-28T04:00:00Z However, some stars are seen to vary in brightness and, for this reason, are called variable stars. Astronomy 2016-10-13T00:00:00Z Most fractal patterns in nature, such as weather, are chaotic, so this aspect of the variable stars came as a surprise. Strange Stars Pulsate According to the "Golden Ratio" 2015-02-09T05:00:00Z It details her life and greatest work: the discovery of an important relationship between the changing brightness of so-called variable stars and the duration, or period, of their light fluctuations. 15 Works of Art Depicting Women in Science 2014-03-07T21:00:00Z Fleming discovered more than 300 variable stars and, in 1899, became Harvard's first curator of astronomical photographs. History: Women who read the stars : Nature : Nature Research 2016-11-22T05:00:00Z It is one of the most luminous in the class of so-called Cepheid variable stars. Hubba-Hubba, Hubble 2013-12-18T02:50:21Z For example, the relationships we have described such as the period-luminosity relation for certain variable stars aren’t exactly straight lines on a graph. Astronomy 2016-10-13T00:00:00Z Proxima Centauri is a variable star, meaning that its brightness as seen from Earth fluctuates from time to time. Hubble Catches A Beautiful Glimpse Of Proxima Centauri 2013-10-30T05:55:00Z The phenomena of variable stars were examined by Herschel as a guide to what might be occurring in our own sun. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" 2012-04-04T02:00:56.447Z Five years later, she determined the relationship between luminosity and period of fluctuation for a class of pulsing variable stars called Cepheids. History: Women who read the stars : Nature : Nature Research 2016-11-22T05:00:00Z The spectrum is of the third type, which includes so many variable stars. Astronomical Curiosities Facts and Fallacies 2012-03-27T02:00:18Z The most distant known variable stars are all cepheids, with some about 60 million light-years away. Astronomy 2016-10-13T00:00:00Z Alpha Herculis, Antares, and Mira, together with orange and reddish stars and most of the variable stars, belong in type III. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z The sun, he knew, rotated on its axis, and he knew that dark spots often exist on its photosphere; the questions that he put to himself were—Are there dark spots also on variable stars? Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" 2012-04-04T02:00:56.447Z As we must get less heat from the sun when it is covered with spots than when there are none, it may be considered a variable star, with a period of eleven years. Meteorology or Weather Explained 2012-02-20T03:00:18.847Z The period of the well-known variable star β Lyræ seems to be slowly increasing. Astronomical Curiosities Facts and Fallacies 2012-03-27T02:00:18Z In this class of variable stars, the time the star takes to go through a cycle of luminosity changes is related to the average luminosity of the star. Astronomy 2016-10-13T00:00:00Z And photo-electric photometry, measuring smaller differences of light than any other method, and providing more accurate light-curves of the variable stars. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z The Persian astronomer Al Sufi, in his "Description of the Heavens," written in the tenth century, describes the well-known variable star Algol distinctly as a red star. Scientific American Supplement, No. 648, June 2, 1888. 2011-12-26T03:00:15.410Z Here we have the grandest of the nebulæ, some of the largest and most beautifully colored stars, star-streams, star-clusters, nebulous stars, variable stars. Astronomy with an Opera-glass A Popular Introduction to the Study of the Starry Heavens with the Simplest of Optical Instruments 2011-07-17T02:00:30.177Z A very curious variable star of the Algol type is that known as R R Draconis. Astronomical Curiosities Facts and Fallacies 2012-03-27T02:00:18Z If observing variable stars doesn’t pique your interest, is there something you think you could do as a volunteer after college that does excite you? Astronomy 2016-10-13T00:00:00Z Spectacular as they are to the layman, nov�, or temporary stars, are to the astronomers simply a class among many thousands of stars which they call variables, or variable stars. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z It is worthy of remark that there exists at the present time, close to the spot indicated, an interesting variable star, which may possibly be identical with the bright star of the second century. Scientific American Supplement, No. 648, June 2, 1888. 2011-12-26T03:00:15.410Z The easiest way to account for it, if not the most satisfactory, is to assume that it is a variable star of long period, and possessing a very wide range of variability. Astronomy with an Opera-glass A Popular Introduction to the Study of the Starry Heavens with the Simplest of Optical Instruments 2011-07-17T02:00:30.177Z A very remarkable variable star has been recently discovered in the constellation Auriga. Astronomical Curiosities Facts and Fallacies 2012-03-27T02:00:18Z This organization of amateur astronomers helps to keep track of variable stars; its site has some background material, observing instructions, and links. Astronomy 2016-10-13T00:00:00Z They may be variable stars which, in a brief period, increase enormously in brightness, and then slowly wane and disappear entirely, or remain of a very faint stellar magnitude. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z It is, we know, a variable star, and stars have been seen to disappear, or even to have a catastrophe happen to them, as the kindling of enormous quantities of gas. Astronomical Myths Based on Flammarions's History of the Heavens 2011-06-24T02:00:15.873Z There are several other variable stars in Cetus, but none possessing much interest for us. Astronomy with an Opera-glass A Popular Introduction to the Study of the Starry Heavens with the Simplest of Optical Instruments 2011-07-17T02:00:30.177Z Taking all the stars visible in the largest telescopes—possibly about 100 millions—the proportion of variable stars will probably be much smaller still. Astronomical Curiosities Facts and Fallacies 2012-03-27T02:00:18Z Amateur astronomers all over the world follow such variable stars patiently and persistently, sending their nightly observations to huge databases that are being kept on the behavior of many thousands of stars. Astronomy 2016-10-13T00:00:00Z Shapley has estimated the distances of many of these bodies, which contain a large number of variable stars of the Cepheid type. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z The earth is a satellite of a variable star. The Universe a Vast Electric Organism 2011-06-09T02:00:22.450Z Sun, opera-glass observations of the, 145. the, a variable star, 72. Astronomy with an Opera-glass A Popular Introduction to the Study of the Starry Heavens with the Simplest of Optical Instruments 2011-07-17T02:00:30.177Z Considering the enormous number of faint stars visible on stellar photographs the number of undiscovered variable stars must be very large. Astronomical Curiosities Facts and Fallacies 2012-03-27T02:00:18Z Among these stars, he discovered some faint variable stars that—when he analyzed their light curves—turned out to be cepheids. Astronomy 2016-10-13T00:00:00Z Some of these are in common use to-day, by navigators, observers of meteors and of variable stars. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z For 100 years astronomers have paid particular attention to a class of variable star known as the Cepheids. Astrophysics and alien intelligence: Talking to the neighbours 2011-04-07T10:58:14Z It should be added that especial care will be taken not to interfere with observations of variable stars now in progress. A Plan for Securing Observations of the Variable Stars 2011-03-20T02:00:35.713Z His study of the variable stars attracted wide attention. Famous Men of Science 2011-03-08T03:00:49.717Z By such studies she and her assistants detected many new nebulæ, double and variable stars, besides spectra of different types and of rare interest. Woman in Science With an Introductory Chapter on Woman's Long Struggle for Things of the Mind 2011-01-12T03:00:29.853Z The numerous variable stars in any one cluster are remarkable for their uniformity. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z Variables of long and short periods.—It must not be supposed that all variable stars are binaries which eclipse each other. A Text-Book of Astronomy 2011-01-05T03:00:57.347Z If they are contained in maps which are available, the letters assigned to each star may be marked on the maps and lines drawn to show with what suspected variable star they are associated. A Plan for Securing Observations of the Variable Stars 2011-03-20T02:00:35.713Z But even after retiring from the Carnegie Observatories and becoming ill, he never stopped working; he published a paper on variable stars only last June. Allan Sandage, Astronomer, Dies at 84; Charted Cosmos?s Age and Expansion 2010-11-18T07:20:00Z It is otherwise with the hypothesis that the sun's heat may, like that of some variable stars, have increased and diminished. The Origin of the World According to Revelation and Science He was the founder of double-star astronomy, and his researches on the light of the stars by the simple method of sequences were the inception of the vast fields of stellar photometry and variable stars. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z The sun's spots may suffice to make it a variable star with a period of 11 years. A Text-Book of Astronomy 2011-01-05T03:00:57.347Z The education of a class of skilled observers would be a work of no less value than the results anticipated from the observation of the variable stars. A Plan for Securing Observations of the Variable Stars 2011-03-20T02:00:35.713Z What does your wisdom make of that wandering and variable star behind those apple boughs?’ Rewards and Fairies The absence of colour changes in variable stars or in the appearance of new stars is further evidence of the same fact. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 5 "Dinard" to "Dodsworth" The spectrum of Omicron Ceti contains many very bright lines, and a large proportion of the variable stars are of this type. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z Algol, the most famous of these variable stars, at its maximum of brightness furnishes three times as much light as when at its minimum, and other variable stars show an even greater range. A Text-Book of Astronomy 2011-01-05T03:00:57.347Z No real advance had been made since his memory blanked out, except for one paper on variable stars which was interesting, but unhelpful. Pursuit We knew him now, of course: it was that variable star, our old acquaintance, Mr. Higginson the courier. Miss Cayley's Adventures South Villa was built about 1836, and an observatory was erected here by Mr. Bishop; this was frequently used by Dawes and Hinde, who here discovered many asteroids and variable stars. Hampstead and Marylebone The Fascination of London The catalogues of variable stars now contain many thousands of these objects. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z So, too, the length of the period fluctuates in many cases, as does every other circumstance connected with it, and predictions of what such a variable star will do are notoriously unreliable. A Text-Book of Astronomy 2011-01-05T03:00:57.347Z Up to that time the only variable stars known were seven in number. Sir William Herschel: His Life and Works But all variable stars need not necessarily be due to the light being intercepted by a dark body. The Children's Book of Stars Leo contains a remarkable variable star, R, deep red in color, and varying in a space of a hundred and forty-four days from the fifth to the tenth magnitude. Pleasures of the telescope An Illustrated Guide for Amateur Astronomers and a Popular Description of the Chief Wonders of the Heavens for General Readers Among the telescopic stars are many of a deep blood-red tint, variable stars being numerous among them. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z The Algol variables.—On the other hand, some variable stars present an almost perfect regularity, repeating their changes time after time with a precision like that of clockwork. A Text-Book of Astronomy 2011-01-05T03:00:57.347Z He discovered double stars, variable stars, nebulæ, and comets; and Mr. William Herschel, of Bath, the amateur astronomer, was gradually emerging from his obscurity, and becoming a known man. Pioneers of Science One very well-known variable star you can see for yourselves, and as an ounce of observation is worth a pound of hearsay, you might take a little trouble to find it. The Children's Book of Stars Scattered over and around the region where the nebul� are thickest we find eight or nine variable stars, three of the most remarkable of which, R, S, and U, may be found on the map. Pleasures of the telescope An Illustrated Guide for Amateur Astronomers and a Popular Description of the Chief Wonders of the Heavens for General Readers It affords exceptional facilities for rapid and convenient observing, as for variable stars, and is adaptable to both refractors and reflectors. Astronomy: The Science of the Heavenly Bodies 2012-03-17T02:01:02.630Z Algol is one of the most conspicuous of these variable stars, as they are called. A Text-Book of Astronomy 2011-01-05T03:00:57.347Z It was not, however, until the close of the nineteenth century that much attention was paid to variable stars. Astronomy of To-day A Popular Introduction in Non-Technical Language These are in the constellation called Perseus, and a little to the right of the middle and lowest one is the only variable star we can see in the sky without a telescope. The Children's Book of Stars But this opinion may not, after all, be correct, for Mr. Bailey's observations show that variable stars sometimes exist in large numbers in clusters, although the variables thus observed are of short period. Pleasures of the telescope An Illustrated Guide for Amateur Astronomers and a Popular Description of the Chief Wonders of the Heavens for General Readers One of the most remarkable of variable stars is called Mira ‘the wonderful,’ in the constellation Cetus. The Astronomy of Milton's 'Paradise Lost' Wolf pointed out in 1852 the striking resemblance in character between curves representing sun-spot frequency and curves representing the changing luminous intensity of many variable stars. A Popular History of Astronomy During the Nineteenth Century Fourth Edition As in many other branches of astronomy, photography is now employed in this quest with marked success; and lately many variable stars have been found to exist in clusters and nebulæ. Astronomy of To-day A Popular Introduction in Non-Technical Language One variable star in Perseus, discovered in 1901, rose to such brilliancy that for one night it was queen of the Northern Hemisphere, outshining all the other first-class stars. The Children's Book of Stars This object was the earliest known case of a variable star, except the so-called temporary stars, to which we shall presently refer. The Story of the Heavens At its eastern border is situated the variable star η Argus, which fluctuates between the first and seventh magnitudes in a period of about seventy years. The Astronomy of Milton's 'Paradise Lost' The luminous outbursts, not the obscurations of variable stars, obey a law analogous to that governing the development of spots on the sun. A Popular History of Astronomy During the Nineteenth Century Fourth Edition The chief discoveries with regard to variable stars have been made by the naked eye, or with a small binocular. Astronomy of To-day A Popular Introduction in Non-Technical Language Since then it has been known as a variable star with a period of about 331 days 8 hours. Myths and Marvels of Astronomy More striking to the general observer than the ordinary variable stars are the temporary stars which on rare occasions suddenly make their appearance in the heavens. The Story of the Heavens A wonderful variable star in Perseus, which goes through its changes in about two days and twenty-one hours. The Sailor's Word-Book An Alphabetical Digest of Nautical Terms, including Some More Especially Military and Scientific, but Useful to Seamen; as well as Archaisms of Early Voyagers, etc. The variable star in Ophiuchus has an analogous system, and observation has already revealed a great number of others. Astronomy for Amateurs The theory in question will, however, apparently account for only one class of variable star, namely, that of which Mira Ceti is the best-known example. Astronomy of To-day A Popular Introduction in Non-Technical Language It is a noteworthy circumstance about the variable star in the Whale, deservedly called Mira, or The Wonderful, that it does not always return to the same degree of brightness. Myths and Marvels of Astronomy The temporary and the variable stars form but a very small section of the vast number of stars with which the vault of the heavens is studded. The Story of the Heavens This class of stars is known as variable stars, and has received the attention of modern astronomers for many years, in order that the cause of their variation might, if possible, be ascertained. Aether and Gravitation It belongs to the category of variable stars which we shall study later on. Astronomy for Amateurs For the other leading type of variable star, Algol, of which mention has already been made, is the best instance. Astronomy of To-day A Popular Introduction in Non-Technical Language The variable star Algol or Caput Medusæ, which marks the head of Gorgon, was accounted 'the most unfortunate, violent, and dangerous star in the heavens.' Myths and Marvels of Astronomy If the sun were withdrawn from us to the distance of Nova Cygni, it would seemingly have dwindled down to an object not more brilliant than the variable star. The Story of the Heavens One of the most interesting of variable stars is that known as Omicron Ceti, whose period of change is about 331 days. Aether and Gravitation And here let us pause for an instant to consider the variable stars. Astronomy for Amateurs That is, however, not the received opinion about variable stars. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told To-night the astronomers on Earth will discover a new star—a variable star as they'll call it—for it will grow dimmer as it moves away from our system. A Honeymoon in Space The most celebrated of all the variable stars is that known as Algol, whose position in the constellation of Perseus is shown in Fig. The Story of the Heavens Argelander was more than any one else the founder of that branch of his science which treats of variable stars. The Reminiscences of an Astronomer There are several others of the same type: these are not, properly speaking, variable stars. Astronomy for Amateurs Many astronomers believe that in "variable stars" we have another star, following that of the dullest red star, in the dying of suns. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told We may remark, in conclusion, that though there are quite a number of variable stars, their nature and the cause of their changes are but imperfectly understood. The Prairie Farmer, Vol. 56, No. 2, January 12, 1884 A Weekly Journal for the Farm, Orchard and Fireside A possible explanation will be considered under variable stars. Recreations in Astronomy With Directions for Practical Experiments and Telescopic Work Some of the variable stars offer strong evidence as to the early life of the double stars. Popular Science Monthly Oct, Nov, Dec, 1915 — Volume 86 I have also taken up the observation of variable stars in a limited portion of the heavens. Men of Invention and Industry One class of these variable stars, which takes its name from the star Algol, is of special interest. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told What does your wisdom make of that wandering and variable star behind those apple boughs?' Rewards and Fairies It is possible that this is a variable star of a period of about three hundred and ten years, and will blaze out again about 1885. Recreations in Astronomy With Directions for Practical Experiments and Telescopic Work So we find parallax, proper motion, double stars, binary systems, variable stars, and new stars all bound together. History of Astronomy Yes," replied the doctor, "our recent investigations of the periods of some of the variable stars show irregularities in brightness, period, and proper motion. Daybreak; a Romance of an Old World But, in a broad sense, the sun-spots and the phenomena connected with them must have a relation to terrestial meteorology, for they prove the sun to be a variable star. Curiosities of the Sky It was the review of a pamphlet by an American astronomer, in which the author announced a conclusive discovery with regard to variable stars. Two on a Tower But these variable stars are still obscure, and we do not need their aid. The Story of Evolution But all variable stars do not suffer the sudden variations of Algol. History of Astronomy I observe from seven or eight till about two in the morning, with a view to my great work on variable stars. Two on a Tower This leads up to the notable fact, first established by Professor Bailey a few years ago, that such clusters are populous with variable stars. Curiosities of the Sky I am preparing a work on variable stars. Two on a Tower ‘I have made an amazing discovery in connexion with the variable stars,’ he exclaimed. Two on a Tower New Stars.—Extreme instances of variable stars are the new stars such as those detected by Hipparchus, Tycho Brahe, and Kepler, of which many have been found in the last half-century. History of Astronomy Compared with comets, variable stars, which he had hitherto made his study, were, from their remoteness, uninteresting. Two on a Tower Moreover, change of color from white to red is characteristic of all variable stars of long period, such as ``Mira'' in Cetus. Curiosities of the Sky |
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