Star (astronomy)

“ The glass reveals to us the fact that the star-dust which we call the Milky Way is an aggregation of innumerable single suns. Sweeping the arching blue with the telescope, we find some stars are golden, some green, others purple, many silvery-white, and some are twins. Probably there is no such thing as stars of the first and second magnitude, as the common expression names them. It is most likely only a question of distance, which regulates the brightness to our vision. ”

“ On account of the immense distances of the stars we can only perceive them to be mere points of light. We can never see a star to be a globe with marks on it like the moon, or like one of the planets—in fact, the better the telescope the smaller does the star seem, though, of course, its brightness is increased with every addition to the light-grasping power of the instrument. ”

“ If you happen to glance at the sky at a point many degrees away from the place where they shine, your eye will inevitably be drawn to them. They have greater attractive power than a single large star, and the effect of their intermingled rays [Pg 110] is truly fascinating. ”

“ Among the stars which we can see with our telescopes, we feel confident there must be many from which the light has expended hundreds of years, or even thousands337 of years, on the journey. When, therefore, we look at such objects, we see them, not as they are now, but as they were ages ago; in fact, a star might have ceased to exist for thousands of years, and still be seen by us every night as a twinkling point in our great telescopes. ”

“ Nebulous stars, which, according to Sir John Herschel's definition, consist of "a sharp and brilliant star, concentrically surrounded by a perfectly circular disk or atmosphere of faint light, in some cases dying away insensibly on all sides, in others almost suddenly terminated." ”

“ The bright point of light which thus seems to us to be a star when we look at it with the naked eye is really another world, or planet as it is called, and very like our own Earth. To prove that this moving point of light is really a world, or planet, and not a distant star, all you need to do is to look at it through a pair of opera glasses, or a small telescope, when it will be seen to be a round body, whereas a star when viewed through the greatest telescope is never larger than a mere point of light. (See Fig. 50.) ”

“ They certainly could, and thus he became convinced that this marvellous object was no mere creation of the fancy, but a veritable celestial body—a new star of surpassing splendour which had suddenly burst forth. In these days of careful scrutiny of the heavens, we are accustomed to the occasional outbreak of new stars. ”

“ These bright patches, then, which form the Milky Way, are really groups of stars or star-clusters, and when some of these clusters are photographed through a telescope as many as 15 or 20 thousand stars can be counted, while the real number of stars that lie beyond and which cannot be seen is past all calculation, and, just think of it, every one of these stars is a Sun as large or larger than our Sun! ”

“ They thus had a telescope more than three hundred feet long as immovable as the solid earth, but, alas for their calculations, the star itself shifted its position, and their gigantic observing tube became useless until modern science inferred from its position the date of their building. How imposing to the imagination this association between a particular star and the mightiest structure made by human hands on the earth! ”

“ But smaller instruments reveal only the in-running star streams and the sprinkling of stellar points over the main aggregation, which cause it to sparkle like a cloud of diamond dust transfused with sunbeams. The appearance of flocking together that those uncountable thousands of stars present calls up at once a picture of our lone sun separated from its nearest stellar neighbor by a distance probably a hundred times as great as the entire diameter of the spherical space within which that multitude is congregated. ”

“ Whenever you have a chance of looking at the heavens through a telescope, you should ask to be shown what is called a double star. There are many stars in the heavens which present no remarkable appearance to the unaided eye, but which a good telescope at once shows to be of quite a complex nature. These are what we call double stars, in which two quite distinct stars are placed so close together that the unaided eye is unable to separate them. ”

“ These brightest stars, which are called first magnitude stars, should be among one's first star acquaintances, for they serve conveniently as guides to locate the other stars, which are also classified according to magnitudes. ”

“ After once recognizing a few of these constellations or beholding through a telescope the glories of a double star or the face of a distant world, one will never again fail through indifference to raise his eyes to the heavens. There is one thing certain—if all the wondrous phenomena of visible stars could be seen on but one of the nights of our long ride about the sun, the civilized world would spend its last cent on glasses and sit up until dawn to feast its eyes on the sublimity of the spectacle. ”

“ If the stand is raised off the ground a foot or so, on a firm foundation, thus bringing the artificial horizon closer to the telescope, faint stars are more easily observed, and the movement of the sextant necessary to keep the star in the field, owing to its motion in the heavens, will be lessened. ”

“ We have every reason for knowing that with larger telescopes, with more sensitive plates, with more prolonged exposures, ever fresh myriads of stars will be brought within our view.
You must remember that every one of these stars is truly a sun, a lamp, as it were, which doubtless gives light to other objects in its neighborhood as our sun326 sheds light upon this earth and the other planets. In fact, to realize the glories of the heavens you should try to think that the brilliant points you see are merely the luminous points of the otherwise invisible universe. ”

“ For it must be remembered that every star is a sun, which, reasoning by analogy, is the centre of a stellar system, just in the same way that our sun is the centre of our solar system. Like our sun, all stars shine by their own light, and the quality of that brilliancy decides the magnitude of the star, the magnitude being indicative of the relative brilliancy of a star rather than its size. ”

“ We stand on our comparatively little earth in what seems the centre of this great universe of stars all around. It is true we do not often see the stars in broad daylight, but they are there nevertheless. The blaze of sunlight makes them invisible. A good telescope will always show the stars, and even without a telescope they can sometimes be seen in daylight in rather an odd way. If you can obtain a glimpse of the blue sky on a fine day from the bottom of a coal pit, stars are often visible. ”

“ Where Man's Earthbound eyes are fortunate to count a thousand stars in a winter sky, here were tens of thousands, bright enough to be a Sirius or a Capella at the bottom of a sink of atmosphere like Earth's—tens of billions of stars in all, whirling close to each other, so that star greets star over distances that are hardly more than planetary. Sol's nearest neighbor star is four light-years away. ”

“ A star below the horizon is visible because refraction raises the image.
A star’s light does not bend uniformly, however. Light rays of different wave lengths bend at different angles, so that when white light is scattered or “dispersed” into its component colors, the blues and greens are bent more than the reds. The density and the temperature of the air also affect the beam, so that as a star’s light travels from the thin upper atmosphere to the denser air near the earth, the colors shift constantly and the star seems to twinkle, flicker, and change in color and brightness. ”

“ It had long been recognised that as the earth describes a vast orbit, nearly two hundred million miles in diameter, in its annual journey round the sun, the apparent places of the stars should alter, to some extent, in correspondence with the changes in the earth's position. The nearer the star the greater the shift in its apparent place on the heavens, which must arise from the fact that it was seen from different positions in the earth's orbit. ”

“ But we can be cunning—we can steadily watch, and the moment we find one of these star-like points beginning to creep about we can pounce upon it. We know by its movements that it is only disguised as a star, but that it is really one of the planets. ”

“ Great progress was made when systematic observations began, such as following the motion of the moon and planets among the stars, and the inferred motion of the sun among the stars, by observing their heliacal risings—i.e., the times of year when a star would first be seen to rise at sunrise, and when it could last be seen to rise at sunset. The grouping of the stars into constellations and recording their places was a useful observation. The theoretical prediction of eclipses of the sun and moon, and of the motions of the planets among the stars, became later the highest goal in astronomy. ”

“ Either that they belong to our stellar system, and hence the stars must be small and young, or they are another universe of millions of suns, so far way that the inconceivable distances between the stars are shrunken to a hand's-breadth, and their unbearable splendor of innumerable suns can only make a gray haze at the distance at which we behold them. ”

“ Southern Irregular and Suspected Variables
[Pg 59]
XII
STAR-CLUSTERS
Endlessly varied is the grouping of the stars. We find solitary stars, twin stars, large stars with small companions, bright stars with faint companions, stars alike in colour and type, stars in strongly contrasted colours, one young, the other aged, stars with invisible companions, couples close enough to touch one another, and couples so distant that the satellite takes more than a century to revolve round its primary. ”

“ The brightest stars, of which there are about twenty, are said to be of the first magnitude. Those just inferior to the first magnitude are ranked as the second; and those just341 lower than the second are estimated as the third; and so on. The smallest points that your unaided eyes will show you are of about the sixth magnitude. Then the telescope will reveal stars still fainter and fainter, down to what we term the seventeenth or eighteenth magnitudes, or even lower still. The number of stars of each magnitude increases very much in the classes of small ones. ”

“ The most superficial view of the sky shews that the stars visible to the naked eye are very unequally distributed on the celestial sphere; the same is true when the fainter stars visible in a telescope are taken into account. If two portions of the sky of the same apparent or angular magnitude are compared, it may be found that the first contains many times as many stars as the second. ”

“ The Milky Way is so full of wonders that centuries of observation and study cannot exhaust them. There is nothing more impressive than to see how it often follows curves of lucid stars as if some mysterious attraction were drawing it toward them; and yet it itself consists of stars.
A few more words of practical advice to the beginner. Let him, at first, confine himself to the bright and conspicuous stars and the striking groups shown in the charts, assigning each to its proper constellation. ”

“ On taking a casual glance at the midnight sky on a clear moonless night, one is struck with the apparent countless multitude of the stars; yet this impression of their vast number is deceptive, for not more than two thousand stars are usually visible at one time. ”

“ The discovery of revolving double stars assured us that the great governing force of the planetary movements, and of our own material existence, sways equally the courses of the farthest suns in space; the application of prismatic analysis certified to the presence in the stars of the familiar materials, no less of the earth we tread, than of the human bodies built up out of its dust and circumambient vapours. ”

“ Star after star was brought to the centre of the field of view of his telescope, and after being carefully examined was then displaced, while another star was brought forward to be submitted to the same process. In the great majority of cases such observations yield really nothing of importance; no doubt even the smallest star in the heavens would, if we could find out all about it, reveal far more than all the astronomers that were ever on the earth have even conjectured. What we actually learn about the great majority of stars is only information of the most meagre description. ”

“ There are found in the sky many thousands of these close double stars, of which some are only optically double—i. e., two stars nearly on line with the earth but at very different distances from it—while more of them are really what they seem, stars near each other, and in many cases near enough to influence each other's motion. ”

“ If now the stars be regarded as motionless and the sun be moving towards a particular point on the celestial sphere, then by an obvious effect of perspective the stars near that point will appear to recede from it and one another on the celestial sphere, while those in the opposite region will approach one another, the magnitude of these changes depending on the rapidity of the sun's motion and on the nearness of the stars in question. ”

“ He also detected spots on the sun’s disk, the phases of Venus, and irregularities on the moon’s surface, and declared the Milky Way to be composed of a countless tract of separate stars.
When we remember the limited power of the telescope of the age, we can but marvel, not at how little, but how much was known regarding the starry skies. ”