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 Until the great Sun has withdrawn his radiance the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.