The starry skies: or, First lessons on the sun, moon and stars

Chapter I. This Earth Of Ours

Once upon a time — thus runs a certain tale-^ there was a man who wanted to see what could be found at the other end of the world.

So he left his home behind him, and started off to explore. He had a toilsome journey. He wandered over wide plains ; he climbed steep mountains ; he forded dangerous rivers ; he crossed stormy seas. Through weeks and months, and even years, he kept straight on, steadily on, patiently on, never turning to right or to left. And at last, what do you think he found ?

Was it a world of giants ? Or a land of fairies? Or a dark ocean, without any further shore ? Or a vast range of hills, reaching skyward ? Or a profound depth, going downward ?

He certainly must have found something, because he came to the end of his journey and travelled no more. He had no need to travel any more. His task was done : the puzzle was found out ; and he had arrived at " the other end of the world."

Only it was no " end " at all, but just the very same spot from which he had started. For he had actually found his way back to his own old home again.

Don't you think he must have been rather astonished ? It was not at all what he had expected.

Suppose that a spider, living in the middle of a very big plain, were to make up his mind to walk to the outside edge of that plain, and see what might chance to be there. And suppose that, having climbed little hillocks, and crossed little brooks, trying always to keep steadily in the same forward direction, he were to find himself all at once back on the very same spot from which he had first set forth !

He would no doubt be a good deal surprised ; and if he had sense to think the matter over he would see plainly that he had not managed, after all, to keep going straight forward, but that he must somehow have turned round without knowing it and gone back to his starting point.

The man in the story made no such mistake, however. He did not turn round. He went always on, and on, in exactly the same direction. Yet in the end he found himself at home ! There is the curious part of the matter.

If the world were a flat plain, like the top of a large round table, the man could not have done this. It would be out of the question. He might have turned round and walked back ; he could not have walked steadily onward and onward, farther and farther away from his home, only to find himself suddenly there again. The thing would be impossible.

Whether any living man ever took such a journey round the world is more than doubtful. But I can assure you of this : tha t if any man ever did take such a journey it would end just as that man's journey is said to have ended. By keeping straight forward, always in one direction, and by going on long enough, he would in time get back to his own house again.

How could he ? That is the question. If a spider were to walk on for ever, straight across a flat plain, he would never get back to his starting-point.

But the world on which we live is not a flat plain. For a long while men believed that it was ; and they made a mistake.

Let us think again of a spider — one of those tiny red spiders often found in a garden — and let us suppose this wee red spider to be standing on a huge round globe, as large as a house. Suppose that the spider, having very short sight, fancied himself to be on a flat table and resolved to take a walk to the further end, to see what he might find there.

You and I, looking on, would know there was no end to the globe : but the spider could not guess this. He would walk on and on, in a straight line, believing himself always to be on a flat surface. And if he contrived to keep a perfectly straight line all round the globe — not an easy thing to do — then, whichever direction he began to go in, the end would be the same : if he kept on long enough he would go round the whole huge ball, and would arrive again at the spot where first he had stood.

If he did not manage to keep quite a direct line, but zigzagged a little to right or left, he would not reach the same spot ; though even then he would get back to the same side of the globe as before. He would find no " end " to it, because a globe, properly speaking, has no " ends."

And this Earth, on which we live, is not flat, like a board or table, but round, like a globe or orange. It is really very like an orange ; for an orange is not a perfect globe, but is a little flattened on its sides, or, as we commonly say, " at the ends." Our Earth also is rather flat in shape at the north and south poles. A round globe, like an orange, or like the Earth, has really no " ends " at all : though we often use the word when speaking of the two poles.

If you were to take such a journey, starting from your home, and keeping a perfectly straight line onwards always in one direction, you too would in time come back to the spot from which you started.

But a journey of this kind would be very hard to manage : far more so than it sounds. Every little hillock, every little streamlet, every house and every tree, to say nothing of rivers and towns, mountains and oceans, would turn you out of your path. By the time you got round the world, although you would return to the same side of the globe from which you first set out, you might be a long way off from the exact spot.

In case you do not know where the two " poles" are, you should ask some one to show you on a school globe. The north pole and the south pole are both very cold parts of our Earth. Ice and snow are there all the year round.

Half way between the north and the south poles is the equator — a line drawn exactly round the whole Earth : and all round the Earth, on or near the equator, are the very hottest countries. About half way between the north pole and the equator, and between the south pole and the equator, are the " temperate " parts of the Earth — not so very cold, or so very hot.

If a man is travelling from near the north pole towards the equator, or from near the south pole towards the equator, he gets into warmer and warmer places.

But if he is travelling from the equator towards the north pole, or from the equator towards the south pole, he gets into colder and colder places.

The right name for a globe-shaped body, like an orange or like the Earth, is a " sphere." Neither an orange nor the Earth is a perfect sphere, because both have flattened ends ; still, the ends are only a little flattened, and we always speak of the Earth as a " sphere."

A " hemisphere " means a " half -sphere." If our whole Earth were cut into two equal-sized pieces each of those pieces would be a " hemisphere."

We always think of the equator as dividing our Earth into two halves. The half towards the north is called " the northern hemisphere ;" and the half towards the south is called " the southern hemisphere."

Since our Earth is said to be a round globe, like a ball, why do we not see over the edge ? A fly, standing on an orange, would have, it is true, a rounded surface just under his feet ; but he could take a good view downward over the edge. It would look like an edge to him, though there is no edge really to a ball.

THIS EARTH OF OURS. II

If our world were as small as an orange, and we by comparison were each as large as a fly, then we should be able to do the same.

But the Earth is huge in size : and we are very tiny — yes, exceedingly tiny, side by side with the great Earth! And the surface on which we stand curves away so very gently, so very gradually, that it looks like a flat surface to us — just as the large globe would have seemed flat to the wee red spider, only very much more so. For the difference in size between the Earth and a man is far greater than the difference between the globe and the wSpider.

You may get some idea of how things are, by standing on the sea-shore, and gazing out to sea. Far away the sky and earth seem to meet in a long line, which we call "the horizon." That line is always around you, on all sides, wherever you are, though often you cannot see it, because of hills or buildings or trees coming between.

Beyond that line the rounded surface of the Earth drops away, so that you can see it no more. It is, in fact, what looked like an edge, to the fly standing on the orange. To us it looks much more as if the ground slanted upwards to meet the sky. But there is no real upward slant. After a certain number of miles, the surface of the ground or the ocean dips downward, out of sight, and all else beyond that line is out of sight also.

Put your eyes close down upon a large schoolroom globe. You will see at once how the solid ball hides from you part of the room. You can see the ceiling, and perhaps the window and the fireplace, but beyond the globe all is hidden. Your horizon, as you stand thus, is just where you seem to see a sort of edge to the globe, beyond which its rounded surface dips away, out of view.

Looking upward into the sky we are able to see enormous distances — hundreds of miles, thousands of miles, millions of miles, billions of miles away ! Light travels to earth from far, far distant stars : and we ' can perceive those feeble gleams because nothing comes between to hide them.

On the Earth it is very different. Here we can commonly see only a few miles off. Not because our eyes are not strong enough : but because the Earth's rounded surface soon dips away, and all beyond that dip is cut off from us by the solid body of the Earth.

On a flat plain, or close to the surface of the sea, our view is very narrow. If we climb a hill we get a wider landscape, because we can see farther over the " dip," and from a mountain-top the view is very greatly increased.

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Still, no matter how high we go, the Earth's surface always stretches away to north and south, to east and west. It always seems to rise and meet the sky, making our horizon-line.

If we could get very, very far off indeed, into the sky, we should then see our Earth floating, like an enormous ball — a huge round solid globe. But this we are never able to do. We know our Earth to be a round ball : but we cannot stand apart and see her to be such.

Did you ever notice a ship " hull-down " on the horizon? — that is, with its masts standing up above the horizon, and its body hidden ?

This again was caused by the shape of the earth : the hull of the ship having dipped down below the horizon, while the masts still stood up within sight.

When we see the Sun in the sky, he is always a round body. But when he sinks at night below the horizon part of the round surface is hidden first, and then the whole. Hidden in the same way : by the Earth's rounded surface coming between him and our eyes.

At the moment when the Sun is all but gone, only one glimmer being visible, you might say of him too, as of the ship, that he is "hulL down."

QUESTIONS.

1 . What is a Sphere ?

A body in the shape of a rounded ball or globe.

2. What shape is our Earth ?

The Earth is a sphere in shape : but not a perfect sphere, because flattened at the north and south poles.

3. What is a hemisphere ?

A hemisphere is a half -sphere.

4. Describe the two hemispheres of the Earth, commonly so called ?

The northern hemisphere is the whole of the Earth north of the equator; and the southern hemisphere is the whole of the Earth south of the equator.

5. What is the Equator?

A line supposed to be drawn round the whole earth, exactly half-way between the north and south poles.

6. What is the horizon ?

The horizon is that line in the distance where the sky and earth seem to meet.

7. What hides all below the horizon ? The solid body of our Earth.

8. How far can a man see on the Earth ?

A few miles, usually. On a hill he has a much wider view.

9. How far can a man see in the sky ?

He can see stars millions and billions of miles away.

10. What is meant by a ship " hull-down?"

A ship " hull -down" is partly above and partly below the horizon.

n. What becomes of the Sun when he sets ? He goes down below the horizon.

12. Is the Sun then too far off for us to see him ?

No : he is only hidden from us after sunset by the solid body of the Earth coming between him and our eyes.

13. Does the Earth's surface really rise to meet the sky?

No : it really drops away, so that beyond a certain line we can no longer see it.

l6 THE STARRY SKIES.

Chapter II. Why Men Do Not Fall Off

We come now to a curious thought.

The world is a round ball; and people live on all parts of it. Therefore, a man on the opposite side from us stands with his feet turned upwards towards our feet and his head pointing in the other direction — " hanging do wn wards, in short," you might say.

This seems extremely odd.

Suppose you hold a big ball, and place a pea on the top of it. The pea will stay where you put it, if you keep your hand steady. But if you place the pea at the side or bottom of the ball it will instantly drop away. Try for yourself, and you will see.

To be sure, a fly or a spider might stand with equal ease on the top or the bottom of the ball. The feet of a fly and a spider are made for clinging and walking in such a position. Alan is not formed to stand or walk upside down, like a fly on the ceiling.

Now, why do n't the people on the other side of the world, in Australia for instance, drop off the earth, and fall away into the sky ?

Of course there is a sky under our feet, just as much as over our heads. The entire world is surrounded on all sides by sky ; not only over our heads, but down under our feet, beyond the solid Earth on which we stand, and in all directions.

If you were to travel round the world, and were to reach Australia — then, as you stood on the ground, your feet would point upwards to the feet of people in the United States ; just as two flies, standing on two opposite sides of a ball, have their feet pointed, those of one fly towards those of the other. It cannot help being so, because of the shape of our Earth.

How do you think you would feel there ? Do you think you would be in danger of dropping off the Earth into the blue sky ?

Not in the least. No more danger of such an accident in Australia than in America. Nothing indeed would astonish you more ! Instead of being disposed to fall from the Earth, you would find it every inch as hard there as here to get away from the Earth. Your own weight would hold you fast to the ground in Australia just the same as in America.

Try to jump up into the air, with all your strength. Try your very utmost ; get as far away as you can from the ground, and stay up in the air as long as possible.

B:l.'!.t Wovkls. 2

Not much good ; is it ? Do what you will, you do not find that you can rise more than a foot or two, and you instantly drop back again. The most powerful leaper can manage at most only a few feet. A man is quite unable to stay up in the air at all, unless something holds him there : far less is he able to drop or float away into the sky.

And the reason why he cannot is that he is too heavy. He is too heavy in America : and he is too heavy in Australia. In both cases he is heavy towards the ground : and he cannot get away from the ground without something to bear him up. It is just as impossible that people in Australia should drop off the world into the sky as that people in America should do so.

But — you will perhaps say — the sky is above us here ; and in Australia it would be under us.

Oh, no ; it would not ! The sky is all round the whole Earth, on every side alike. In all parts of the world people have the sky over their heads and firm ground beneath their feet.

The Australian sky is under the feet of those who live in North America : that is true. But then it is no less true that the North American sky is under the feet of those who live in Australia. To you the Earth is underneath : the sky is overhead. To an Australian also the Earth is underneath and the sky is overhead. All round the world it is the same. Down means

WHY MEN DO NOT FALL OFF. IQ

always towards the ground. Up means always towards the sky.

If you hold up a stone in the air, and let it go, what happens ? The stone drops at once to the ground.

If you fling a ball into the air, what happens ? The ball goes a little upwards, carried by the force of your fling : but soon it curves over and comes to the ground.

If you tilt up a jug full of water, what happens ? The water pours down upon the floor.

If a man steps over a precipice-edge, what happens ? He falls to the bottom, and is most likely killed.

But these things are not more true of the United States than of Australia. All round the world, in every part, it is the same. Water always flows downward. Loose bodies always drop downward, unless kept up by something.

We have been asking why it is that people never drop off from the Earth into the sky. Of course nobody ever asks that question about the part of the Earth on which he happens to be. Whether he is in England, or in America, or in Australia, he knows very well that he is in no danger of "dropping off." The very idea as to himself would seem absurd. To " drop off " would really be to rise upward into the sky : and he feels that he is much too heavy for that. It is only when he thinks about the other side of the world, and about people walking there with their heads hanging downward

But they do not walk with their heads hanging downward. Their heads, like ours, point upward to the sky ; and their feet, like ours, rest firmly on solid ground; and they too, like us, are heavy towards the Earth. It is as impossible for a man in Australia as for a man in England or America to " drop off " the Earth — in other words, to rise upwards towards the sky. His own weight holds him down.

What do we mean by "weight?" What makes a man " heavy ?"

He is made heavy by the Earth's pulling or attracting him ; and this gives him weight.

And how does the Earth pull ?

There I cannot tell you much. We know that the Earth does pull : but how she pulls is another question. We name that pulling "Attraction," and sometimes we call it by a longer word, "Gravitation." But not the very wisest man living can explain to us exactly what attraction is. He can only tell us what it does.

Did you ever see a magnet ? It is generally shaped rather like a horse-shoe : and the two ends have an odd drawing power. A number of tiny iron shavings, held near enough, will jump up to meet the magnet as if they were alive.

This is because the magnet pulls them towards itself. Sometimes a toy-box of metal ducks or fishes is sold, with a magnet ; and they will follow the magnet to and fro, in a basin of water.

Now our Earth seems to be a sort of huge magnet, with power to pull towards herself, not only iron or steel, but every single thing and creature upon her surface. Not only on one side of the Earth, but around the whole globe, on every part, there is the same steady downward drag, always toward the centre of the Earth.

The mountains are pulled earthward : so are houses and trees, rocks and soils, seas and rivers, animals and men. There is not a single thing on or near the surface of our Earth which is not thus drawn earthward.

If it were not for this attraction nothing would have any weight. When you leap upward and instantly drop back it is because the Earth drags you down. Without such dragging you would not be heavy at all.

Think what that would mean. You might jump over the highest mountains with ease: or you might spring away into the sky, and never return : only, of course, there is no air, far away in the sky, and you could not breathe without air.

But if the Earth did not attract we should have no air here either, because it would long ago have all wandered away. Earth's strong attraction holds the air prisoner, as well as all other things upon her surface.

Now do you begin to see how it is that people do not fall away into the sky, from any part of Earth ? They are held firmly down by Earth's perpetual drag, which gives them weight. Whether they are in England or in Australia, in Asia or in America, makes no difference. The pull is always downward, always earthward. The difficulty always is to get away from earth, upward, toward the sky.

So when we think of the world as a whole we have to remember that in the surrounding sky there is no true "up" or "down" in one direction more than another. " Up " is towards the sky for each man, from that part of Earth on which he stands : and as our Earth is ever turning round and round our " up " is constantly changing its direction.

'Perhaps you will think that I am rather slow in getting to my subject of "The Starry Skies." Two whole chapters first about this old Earth of ours !

But indeed I have not been slow : for on the very first page we started right off with a Bright World in the Sky.

By this time you know that our world is actually in the sky, just as much as the sun and moon are in the sky. We are in the moon's sky, and in the sun's sky, and in the sky of all other planets and all other stars. For our Earth floats in the same boundless sky-depths as all of them, those sky-depths which are usually known by the name of Space.

So now, when " Space " is spoken of, you will understand. You will know that it means the Sky, in which float all the heavenly bodies.

"Only" — you will perhaps say — "the Moon and the Sun are bright ; and so are the Stars. But our dull old world is not bright at all."

That is a great mistake, I assure you. Our world is very bright indeed. She shines with an exquisite radiance. Not indeed with such a dazzling glory as the Sun, but quite as brightly as the Moon.

Have you ever noticed how the ocean shines, and flashes forth light, when the Sun beats down full upon it ? Or, again, have you not been struck with the shining of white clouds in sunlight ? More or less the whole surface of our Earth catches and gives forth again the brightness that comes to her from the Sun.

If we could travel away from the Earth to a good distance — say, as far as to the Moon — we should see the round Earth like an enormous, brilliant Moon in the sky, only far larger and more beautiful than our Moon ever looks to us.

Some parts would be darker, some more shining ; but as a whole the Earth would be a splendid sight.

Not bright ? Yes, indeed ; we are living on a very bright world indeed, though we cannot always see her radiance.

QUESTIONS.

1. What is Space ?

By Space we mean Sky — the whole great Sky, in which are all the heavenly bodies.

2. Is our Earth in the Sky ?

Just as truly as the Sun and Moon are in the Sky. They are in our sky, we are in their sky.

3. Does our Earth float in Air ?

No ; she floats in the Sky : and the air is a part of the Earth.

4. Do people on the other side of the globe walk head downwards ?

No; they walk as we do, on firm ground, with the Sky over their heads.

5. What is meant by " up " and " down " to us on Earth ?

On every part of the Earth up is always toward the Sky, and down is always toward the Earth.

6. Give some examples of the way in which all things move earthward.

Water always pours downward. A stone flung, or a ball dropped, always reaches the ground.

7. Why do things descend thus ?

Because of their own weight or heaviness.

8. What causes weight ?

The pull of the earth.

9. Give two other names for that " pull." Attraction and Gravitation.

'10. Tell me a few things that are pulled earthward. Men, animals, trees, houses, rocks, cities, hills, mountains, lakes, rivers, oceans, air, clouds, etc.

11. What keeps people on the other side of the Earth . from dropping off into the sky ?

They cannot possibly drop off ; because the sky there is upward, the same as here.

12. What would " dropping off " really be ?

It would be rising upward into the sky.

13. Why should a man not rise upward ? He cannot, because he is too heavy.

14. He is heavy towards what ?

He is heavy towards the Earth, because of the Earth's attraction.

15. Is he as heavy in Australia as in the United States ? Exactly the same.

1 6. In what direction is he pulled there ?

Towards the Earth. All round our whole world the pull is towards the centre of the Earth.

17. Can our Earth be called " a bright world ?"

Quite as much so as other planets. If we were far enough off she would be seen by us to shine with reflected sunlight, like the Moon.

Chapter III. By Day And By Night

Let us take a good look up into the sky, and see what is to be found there.

First, by day. Beginning- in the early morning, just before sunrise, we have perhaps a clear sky, grayish rather than blue, and towards the east a brightening glow shows that the Sun is about to appear. That glow grows stronger and stronger, and soon a tiny glimmer creeps up over the rounded surface of our earth. Then the broad golden face follows, till the sun is visible, and full daylight has arrived.

But the Sun does not stand still there, low down on the horizon. He goes on rising higher and higher, " climbing the heavens " steadily, one hour after another. At mid-day — twelve o'clock — he has reached his very highest point. Then he begins to descend, moving downward towards the west till he reaches the western horizon and vanishes from our sight.