CHAPTER IV.. How the World Spins.

HOW THE WORLD SPINS.

In our last chapter we saw how the Sun rises and sets in the day, and how the Moon and Stars rise and set in the night.

True, they also rise and set, by day as well as by night. The Moon often does so: and all day long there are Stars coming up in the east, and stars crossing the sky, and stars going down in the west. But we cannot see them. Until the great Sun has withdrawn his radiance the little star-gleams are hidden from us, and even the Moon can seldom be caught sight of.

In the daytime, when you look up into the blue sky, and see a blaze of sunlight, you should sometimes remember that the stars are there. All day long, as well as all night long, the stars are there, shining just as usual. All day long, as well as all night long, they are moving steadily across our sky: rising, marching onward, and setting. We cannot see them; but that is because our eyes are weak, not because the stars themselves do not shine.

So by day and by night the heavenly bodies seem to be ever on the move. No matter what part of the world you may be in--whether England or America, whether India or Australia--still you will find them moving. By day you will see the Sun rising in the east, journeying towards the west, and setting. By night you will see the Moon, and most of the stars, rising in the east, journeying towards the west and setting.

This goes on continually. It is always the same. Year after year, there is no change.

The Sun rises in one spot, crosses the sky, sets; and then a few hours afterwards rises again in very nearly the same spot as before, to cross the sky by very nearly the same path, and to set in almost exactly the same part of the western horizon. Each day there is a tiny, very tiny, difference; but by the end of twelve months the Sun gets back to exactly the same spot in rising and setting as in the previous year. And most of the stars follow the Sun’s example.

Why should not one fix upon a bright star overhead, and hurry along on the ground, just as fast as the star goes, so as to keep it overhead longer--to keep it in sight?

There is no reason why one should not do this, if only one could get along fast enough.

It would have to be very rapid travelling. If you wished to keep that star in sight, overhead, for twenty-four hours, you would have to do--what do you think? You would have to rush round the whole world in twenty-four hours!

If you could possibly manage to do that, you might possibly choose any bright star overhead that you liked, and keep it in view all night; in fact for two nights, with no day between; for you would journey with the night.

Or if you chose to follow the Sun by day, keeping him overhead in your rapid rush over continents, and mountains, and oceans, you might have a double day of twenty-four hours, with sunshine all the while and no darkness.

But think what such a rush would mean! Think how big the world is! People sometimes do travel all round the whole earth, and the journey takes them many months. Even if they stopped to look at nothing by the way, and went as fast as possible, and cared nothing about being tired--even then, at the very least, it would take them many weeks.

To get round the world, on the Equator, or from England, or from the United States, or from Australia, in twenty-four hours, is a thing which no living man could ever do! The Sun and the stars go much too fast for us.

They are seen to whirl round the whole earth, swiftly and calmly and easily, with no manner of fuss or difficulty, once in every twenty-four hours!

Ah! but do they? That is the question. Do they really all whirl round and round, at this rate?

When you take a journey in a train, and look out of the window, what do you see?

Everything seems to be moving. The more distant hills travel slowly; fields and villages speed at a good rate; houses and hedges near at hand rush by; and the telegraph poles flash past as if running away. But one house does not go one way and another house in the opposite way. All of them journey in the same direction.

Do they really journey? Are the fields and hills, the villages and trees and telegraph poles, all spinning swiftly along, while you in your train sit quite still, not moving at all?

It must be one of the two things: either they are on the move, and you are quiet; or else they are quiet, and you are yourself rushing along, so that they only seem to move.

You would not have much difficulty in deciding. Even if you did not feel the carriage in which you sit to be shaking and jarring with its own rush, still you would count it easier to believe that the train was going forward than to think that all the hills and fields and trees and houses were speeding the opposite way.

It is almost the same thing with our earth. We see the Sun, and the Moon, and all the stars, hurrying past, and we have to believe one of two things: either they are all moving, and we are still; or else we are moving and that makes them only seem to move.

For a long while people were not quite so sensible about the heavenly bodies in the sky as you would be about the houses and fields seen out of a train. It seemed to them easier to believe that all the stars went round and round the earth, than to believe that the solid earth herself moved.

There was this excuse, that the earth does not jar and rattle like a train, and also that the distances of the stars cannot be easily seen at a glance, like the distances of hills and valleys.

We have learned differently now. We know that our earth does indeed move; and that the daily journey of the Sun, the nightly journey of the moon and planets and stars, is not a real journey. It is only a seeming journey. They seem to move, because our earth truly moves, just as the hedges and trees seem to move when looked upon out of a train which really moves.

Day and night the earth moves. Day and night, year after year, she spins, like an enormous top, upon her axis.

By the “axis” of the earth I mean a straight line through her centre, from the north pole to the south pole.

If you have a school-globe you will see that it turns round and round upon a kind of large pin, which reaches from one pole to the other. That is its “axis,” and that is how the Earth spins.

Or you may stick a long bonnet-pin through an orange, from one flattened end to the other, and spin the orange upon that pin, which is then the axis of the orange.

A spinning-top also has an axis. There is no pin stuck through the top; but as it whirls round, humming, and remaining in one spot, there is a line from top to bottom of it which does not seem to move. The whole top whirls round this line, which again is the axis of the top.

Our Earth has no huge pin passed through her body; but, like the top, as she spins there is a line straight through her, from the north to the south pole, which keeps still, while round it whirls the whole big body of the Earth. And that is the Earth’s axis.

If a man stands close to the north pole, or close to the south pole, at either end of the axis, he moves very little. But if he is far away from the poles, on or near the equator, the ground on which he stands rushes along at a great rate, carrying him with it.

He does not feel the movement. He is not shaken or jolted. The Earth whirls very smoothly. As she spins she carries with her, on her surface, all the mountains and seas, the hills and valleys, the trees and towns and villages, yes, and the very air which we breathe. Nothing is left behind.

So the man cannot know how fast he is going by any feeling of his own. He can only know it by looking up into the sky. There he sees the Sun, the Moon, the Planets, the Stars, all hurrying past. Why? Because he is hurrying past--not because they are.

They all go in the same direction, from east to west. We have seen this plainly. It is not a journeying of some stars one way, and some stars another way. It is one great sweep of the whole heavens from the east of the world toward the west of the world.

And the reason of this is that our Earth spins or whirls from the west to the east.

That is what makes the Sun and the Stars all seem to rise in the east and set in the west.

In the morning, when you get up early, and look towards the east, you are gazing at that part of the sky towards which you are travelling. The Sun is not coming to meet you, but you are going to meet him. This solid world on which you stand is whirling like a big teetotum, carrying you round in his direction.

So presently you see him seem to creep up over the horizon. And by-and-by, at mid-day, the moving surface of the Earth has carried you on almost underneath him. And later in the evening, as you are still whirled on toward the east, you leave the Sun behind you, in the west.

But still he goes on rising to other parts of the world, as country after country spins round into his light.

At night it is the same thing over again. Each star that rises only seems to rise, because we on the Earth’s surface are whirled round towards that part of the sky in which the star always shines. Then we pass on, and leave that star behind, as we left the Sun; and we say that it has set.

But the Sun and the Star have not moved. It is we who have moved; not they.

So when we think of the Earth as a whole we have to picture her, not only as a large solid globe floating in the sky, but as a spinning globe, ever turning round and round like a top or a teetotum.

It is this whirling movement of the Earth which gives us Day and Night.

For, as our Earth floats and spins, one side of her is always turned toward the Sun, and is in daylight; the other side is turned away from the Sun, and is in darkness. Each land and ocean in turn comes towards the Sun in the east and passes onward, leaving the Sun in the west.

And around, on all sides, is the great Sky, which sometimes we name “Space,” and which sometimes we call “The Heavens.” In that Sky float all the Worlds and all the Stars, as well as our Earth and our Moon and Sun. And in that sky is GOD himself.

HE made the Sky, the Sun and the Moon and the Earth, the Planets and the Stars; and HE is everywhere, around and amidst and in them all. Wherever in the boundless reaches of Space we may wander in thought, we shall never find a spot where God himself is not.

QUESTIONS.

1. Where are Stars in the day-time?

In the sky: only we cannot see them.

2. Could a man travel round the world from America or England as fast as a Star travels?

No: he would have to go round the whole world in twenty-four hours.

3. Do the Stars really journey round the world?

They only seem to do so.

4. But the Sun rises and sets, does he not?

He seems to do so. It is really our Earth that moves.

5. In what way does the Earth move?

Once in twenty-four hours she whirls round on her axis from west to east.

6. What is the Earth’s axis?

An imaginary line through her centre, from the north pole to the south pole.

7. How does our Earth’s spinning make the heavenly bodies seem to move?

A little in the same way that, when we journey in a fast train, houses and trees and fields seem to go the other way.

8. Did people always know that the Earth whirled round?

No; they used to think it was a real journeying of the Sun and Stars in our sky.

9. Where does the surface of the Earth move fastest?

On the equator. The ground there rushes at a great speed.

10. Where does it move most slowly?

At the poles.

11. Does a man standing on the equator feel how fast he moves?

No; because the Earth moves smoothly; and everything on the ground and in the air is carried along by the Earth.

12. How can he know that the Earth moves?

By looking up into the sky--like a man in a train looking out of the window.

13. How does the Earth’s spinning make the Sun seem to rise?

The Sun remains fixed--but a man on the Earth is carried round towards the east, and so the Sun seems to come towards him from the east.

14. And how does it make the Sun seem to set?

The man is still carried on towards the east, and by-and-by he leaves the Sun behind him in the west.