Astronomy

Another science which stands in an intimate relation to religion, is Astronomy.

This sublime science teaches us the magnitudes and distances of the heavenly bodies, their arrangement, their various motions and phenomena, and the laws by which their movements are regulated. It presents to our view objects the most wonderful and sublime; whether we consider the vast magnitude of the bodies about which it is conversant—their immense number—the velocity of their motions—the astonishing forces requisite to impel them in their rapid career through the regions of the sky—the vast spaces which surround them, and in which they perform their revolutions—the magnificent circles they describe—the splendor of their appearance—or the important ends they are destined to serve in the grand system of the universe. Having adverted to this subject, when illustrating the Omnipotence of the Deity, I shall here simply state a few additional facts with respect to the general appearance of the heavens, the bodies which compose the planetary system, and the discoveries which have been made in the region of the stars.

When we lift our eyes toward the sky, we perceive an apparent hollow hemisphere, placed at an indefinite distance, and surrounding the earth on every hand. In the day-time, the principal object which appears in this hemisphere is the sun. In the morning, we see him rise above the distant mountains, or from the extremity of the ocean: he gradually ascends the vault of heaven, and then declines and disappears in the opposite quarter of the sky. In the northern parts of the globe, where we reside, if, about the 21st of March, we place ourselves on an open plain, with our face toward the south, the sun will appear to rise on our left, or due east, about six in the morning, and about the same hour in the evening he will set due west. In the month of June, he rises to our left, but somewhat behind us, in a direction toward the north-east, ascends to a greater hight at noon than in the month of March, and, after describing a large arc of the heavens, sets on our right and still behind us, in the north-western quarter of the sky. In the month of December, if we stand in the same position, we may observe, without turning ourselves, both his rising and setting. He rises in the south-east, ascends to a small elevation at noon, and sets in the south-west, after having described a very small arc of the heavens. Every day he appears to move a little toward the east, or contrary to his apparent diurnal motion; for the stars which are seen to the eastward of him, appear every succeeding day to make a nearer approach to the place in which he is seen. All the variety of these successive changes is accomplished within the period of 365 days 6 hours, in which time he appears to have made a complete revolution around the heavens from west to east.

The moon is the next object in the heavens which naturally attracts our attention; and she is found to go through similar variations in the course of a month. When she first becomes visible at new moon, she appears in the western part of the heavens, in the form of a crescent, not far from the setting sun. Every night she increases in size, and removes to a greater distance from the sun, until at last she appears in the eastern part of the horizon, just as the sun disappears in the western; at which time she presents a round full-enlightened face. After this she gradually moves farther and farther eastward, and her enlightened part gradually decreases, until at last she seems to approach the sun as nearly in the east as she did in the west, and rises only a little before him in the morning, in the form of a crescent. All these different changes may be traced, by attending to her apparent positions, from time to time, with respect to the fixed stars.

A dark shadow is occasionally seen to move across the face of the moon, which obscures her light, and gives her the appearance of tarnished copper. Sometimes this shadow covers only a small portion of her surface; at other times it covers the whole of her disc for an hour or two, and its margin always appears of the figure of a segment of a circle. This phenomenon, which happens, at an average, about twice every year, is termed an eclipse of the moon. It is produced by the shadow of the earth falling upon the moon, when the sun, the earth, and the moon are nearly in a straight line; and can happen only at the time of full moon. Sometimes the moon appears to pass across the body of the sun; when her dark side is turned toward the earth, covering his disc either in whole or in part, and intercepting his rays from a certain portion of the earth. This is called an eclipse of the sun, and can hap- page 79 pen only at the time of new moon. In a total eclipse of the sun, which seldom happens, the darkness is so striking, that some of the planets and sometimes the larger stars are seen, and the inferior animals appear struck with terror.

Again, if on a winter's evening, about six o'clock, we direct our view to the eastern quarter of the sky, we shall perceive certain stars just risen above the horizon; if we view the same stars about midnight, we shall find them at a considerable elevation in the south, having apparently moved over a space equal to one-half of the whole hemisphere. On the next morning, about six o'clock, the same stars will be seen setting in the western part of the sky. If we turn our eyes toward the north, we shall perceive a similar motion in these twinkling orbs; but with this difference, that a very considerable number of them neither rise nor set, but seem to move round an immovable point, called the north pole. Near this point is placed the pole star, which seems to have little or no apparent motion, and which, in our latitude, appears elevated a little more than half way between the northern part of our horizon and the zenith, or point above our heads.

The following cut, which represents the principal stars in the constellations Ursa Major and Ursa Minor, will enable the reader to recognize the Pole star, by attending to the following directions. The seven stars in the lower part of the figure represent Ursa Major, or the Great Bear, sometimes known by the names of the Plow and Charles's Wain. The stars on the upper part represent Ursa Minor, or the Little Bear, the largest star of which, on the right hand side, is the Pole star. About the beginning of November, at 6 or 7 o'clock in the evening, the Great Bear will appear near the north, at a low elevation above the horizon, and nearly in the position here represented. The two stars on the right hand side of the Great Bear are called the Pointers, and are distant from each other about 5 degrees. If a line connecting these stars be considered as prolonged upward to a considerable distance (about 29 degrees), until it meet the first bright star, that star is the Pole star, which is here represented at the higher part of the figure. Were the same observation made about the middle of April, at 10 o'clock in the evening, the Great Bear will appear almost directly over our heads, above the Pole star, and then we must conceive the line connecting the two Pointers as drawn downward toward the Pole star. At different times of the night, and at different periods of the year, the Great Bear will appear to be in different positions with respect to the Pole star, sometimes below, sometimes above, and at other times to the east or the west of it. But in all positions, a line drawn through the Pointers will always direct the eye to the Pole star.

A person who has directed his attention to the heavens for the first time, after having made such observations, will naturally inquire—Whence come those stars which begin to appear in the east? Whither have those gone which have disappeared in the west? and, What becomes, during the day, of the stars which are seen in the night?—It will soon occur to a rational observer, who is convinced of the roundness of the earth, that the stars which rise above the eastern horizon come from another hemisphere, which we are apt to imagine below us, and when they set, return to that hemisphere again; and that the reason why the stars are not seen in the day-time, is not because they are absent from our hemisphere, or have ceased to shine, but because their light is obscured by the more vivid splendor of the sun.^* page 80 From such observations we are led to conclude, that the globe on which we tread is suspended in empty space—is surrounded on all sides by the celestial vault—and that the whole sphere of the heavens has an apparent motion round the earth every twenty-four hours. Whether this motion be real, or only apparent, must be determined by other considerations.

Such general views of the nocturnal heavens, which every common observer may take, have a tendency to expand the mind, and to elevate it to the contemplation of an Invisible Power, by which such mighty movements are conducted. Whether we consider the vast concave, with all its radiant orbs, moving in majestic grandeur around our globe, or the earth itself whirling round its inhabitants in an opposite direction—an idea of sublimity, and of almighty energy, irresistibly forces itself upon the mind, which throws completely into the shade the mightiest efforts of human power. The most powerful mechanical engines that were ever constructed by the agency of man can scarcely afford us the least assistance in forming a conception of that incomprehensible Power, which, with unceasing energy, communicates motion to revolving worlds. And yet, such is the apathy with which the heavens are viewed by the greater part of mankind, that there are thousands who have occasionally gazed at the stars for the space of fifty years, who are still ignorant of the fact, that they perform an apparent diurnal revolution round our globe.

Again, if we contemplate the heavens with some attention, for a number of successive nights, we shall find, that by far the greater part of the stars never vary their positions with respect to each other. If we observe two stars at a certain apparent distance from each other, either north or south, or in any other direction, they will appear at the same distance, and in the same relative position to each other, the next evening, the next month, and the next year. The stars, for instance, which form the sword and belt of Orion, present to our eye the same figure and relative aspect, during the whole period they are visible in winter, and from one year to another; and the same is the case with all the fixed stars in the firmament. On examining the sky a little more minutely, however, we perceive certain bodies which regularly shift their positions. Sometimes they appear to more toward the east, sometimes toward the west, and at other times seem to remain in a stationary position. These bodies have obtained the name of planets, or wandering stars; and in our latitude are most frequently seen, either in the eastern and western, or in the southern parts of the heavens. Ten of these planetary orbs have been discovered: six of which are, for the most part, invisible to the naked eye. By a careful examination of the motions of these bodies, and their different aspects, astronomers have determined that they all move round the sun as the center of their motions, and form, along with the earth and several smaller globes, one grand and harmonious system. This assemblage of planetary bodies, is generally termed the Solar system, of which I shall now exhibit a brief outline.