POPULAR LESSONS IN ASTRONOMY.
POPULAR LESSONS IN ASTRONOMY.
THE EARTH IN ITS RELATION TO THE SUN, MOON AND STARS.
§ 1. The Earth on which we live, and on which plants, trees and animals successively live and die, is only a small part of the world; it is but one of the smallest bodies in the Universe. To the world belong yet theSunfrom which we receive warmth and light, theMoon, and an innumerable class of bodies, which, at night, appear to us as so many points of light. These are calledStars.
The reason why the Stars appear to us so small, is because they are so far from us; and things appear smaller in proportion as they are farther removed from us. This you will have noticed, when looking from a high steeple on the people below, or on a vessel far out in the harbour, or on a chain of mountains at a great distance.
The reason why the Stars appear to us so small, is because they are so far from us; and things appear smaller in proportion as they are farther removed from us. This you will have noticed, when looking from a high steeple on the people below, or on a vessel far out in the harbour, or on a chain of mountains at a great distance.
§ 2. Most all Stars appear to us, every night in the same position; they seem actually to befixedin the heavens; and for this reason they are calledfixed Stars. There are however Ten others, of which it has been ascertainedthat they move regularly round the Sun in large circles. These are calledPlanetsorwandering Stars.—The fixed Stars are supposed to be similar to the Sun, in as much as they are bodies which have their own light. The Planets, on the contrary, are of themselves dark bodies, and receive, like our Earth, light and warmth from the Sun. We see them only in consequence of the solar light which theyreflectfrom their surfaces, and this is the reason why they appear to us as bright as the other Stars.
§ 3. The discoveries of Philosophers have proved beyond a doubt,that our Earth itself is one of those Planets, which move round the Sun in stupendouslarge circles, whose grandeur is hardly conceived by the most powerful imagination.Our Earth, therefore, is, itself, a Wandering Star, and the line in which it moves round the Sun is called itsWayorOrbit.
§ 4. The Planets, together with our Earth keep each a certain fixed distance from the Sun. On this account they do not disturb each other in their orbits. But they vary from each other in magnitude; although all of them (consequently also our Earth) have aroundshape, similar to a ball.
In former times men believed that the Earth was flat, or a circular plate on all sides surrounded by water. But this is not true. For it has been proved by a great many observations and actual measurements, that the Earth has a spherical (ball-like) form. Moreover there are navigators who have actuallysailed round the world, and who have noticed the fact that at sea, the tops of distant objects are seen sooner than the rest; which again proves the spherical form of our Earth. For an illustration you may look at the adjoining plate Plate No.I.The man who is represented as standing on a portion of our Earth, will at first only see the topmast of a vessel at sea; when she comes nearer his eye will discover a much greater portion of her; but when in the third position every part of the vessel will be visible.
In former times men believed that the Earth was flat, or a circular plate on all sides surrounded by water. But this is not true. For it has been proved by a great many observations and actual measurements, that the Earth has a spherical (ball-like) form. Moreover there are navigators who have actuallysailed round the world, and who have noticed the fact that at sea, the tops of distant objects are seen sooner than the rest; which again proves the spherical form of our Earth. For an illustration you may look at the adjoining plate Plate No.I.
The man who is represented as standing on a portion of our Earth, will at first only see the topmast of a vessel at sea; when she comes nearer his eye will discover a much greater portion of her; but when in the third position every part of the vessel will be visible.
§ 5. Some of the Planets are, in their motion round the Sun,accompanied by other dark bodies, which, like the Planets themselves, receive light and heat from the Sun. These are calledSatellitesorMoons. Such a Satellite is theMoon which accompanies our Earth; and there are Planets (as we shall see hereafter) which have Four and Six, and One that has even Seven Moons.
§ 6. Besides the Planets and Moons there is yet another class of bodies, moving round the Sun in exceedingly long ovals. They are but seldom visible, and are distinguished from other heavenly bodies by a tail which is often three, four, and more times larger than the body itself. These are calledComets; but their number has not, as yet, been precisely ascertained.
§ 7. The Planets, Moons and Comets, together with the Sun around which they move, form what is called ourSolar System. But what will you say, if you are told that each fixed Star in the firmament is a Sun which, like our’s, has its Planets and satellites and Comets; in short, that each fixed Star is the centre of a solar system, a thousand and more times larger than our own!! But how infinitely great must God’s Creation appear to us, when we reflect that all these globes, as well as our own, may be inhabited by reasonable beings!!!
No. I.
No. I.
No. I.
RECAPITULATION OF LESSON I.
[If the pupil has learned and understood this lesson, it may perhaps be not unreasonable to suppose he will like to know something more about the Planets and the Moons in our system. But the teacher ought not to allow him to enter upon the second lesson, before he has recapitulated the first.]
[If the pupil has learned and understood this lesson, it may perhaps be not unreasonable to suppose he will like to know something more about the Planets and the Moons in our system. But the teacher ought not to allow him to enter upon the second lesson, before he has recapitulated the first.]
QUESTIONS.
[§ 1.] Does the Earth, or the globe on which we live, comprise the whole world which God has created? Is our Earth any considerable portion of the Universe? What other bodies belong to it? Why do the Stars appear to us so small?
[§ 2.] Do all the Stars which we see remain in the same position? What are those called which remainfixed? What, those, which are moving regularly round the Sun? What are the fixed Stars supposed to be? Have the Planets any light of their own? From what body do the Planets receive their light?
[§ 3.] What important discoveries have Philosophers made respecting the nature of our Earth?
What is the line in which our Earth moves round the Sun, called?
[§ 4.] Why do the orbits of the different Planets not disturb each other? Are all Planets of the same magnitude? What is their shape? What is the shape of our Earth? What reason have you to believe, that the Earth is round? Explain PlateI?
[§ 5.] By what are some Planets in their motion round the Sun accompanied? What are the bodies which accompany them called? What body accompanies our Earth in its motion round the Sun? Are there Planets which have more than One Moon?
[§ 6.] What other class of bodies is there, besides the Planets and the Moons? Are these bodies always visible? By what are these bodies distinguished? What are they called?
[§ 7.] What do the Planets, Moons and Comets, together with the Sun, round which they move, form? What is each fixed Star supposed to be?