THE SUN BY DAY.
If you look at the Sun in our sky before he sets, and then, a little
later, at the Moon when she has risen, it might seem that the two are
very much of the same size and very much at the same distance.
To be sure, the Sun is the brightest; a great deal the brightest. He
has such a dazzling face that you cannot look at him steadily. But
certainly he does not look larger than the Moon.
What do you think the size of the Sun really and truly is?
Once upon a time people supposed him to be about as big as he looked.
And afterwards they fancied that perhaps he might be even as large as a
little country called Greece, a much smaller country than England.
But the Sun is bigger than England, bigger than America, bigger than
all the oceans of the Earth heaped together; bigger than the Moon,
bigger than the whole Earth, bigger than Earth and Moon rolled into
one--oh, we are a long way off yet from the truth!
The Sun is a round globe in shape, like the Earth and the Moon. But he
is ever so much larger.
Our Moon, as you know, is about two thousand miles through from side
to side. Our Earth is nearly eight thousand miles through. But that
enormous globe, the Sun, is--how much do you guess?--is about _eight
hundred and fifty thousand miles through_!
Can you picture to yourself what this means? Rather hard, is it not!
The Earth seems so big to us who live upon its surface, and yet she is
so small beside the great Sun!
Suppose you had a huge hollow ball the size of the Sun. And suppose
you wished to run through that hollow ball a very, very long
knitting-needle--eight hundred and fifty thousand miles long--so as
just to go from side to side of the huge ball. And suppose upon that
big knitting-needle you wished to string a great many Earths or Moons,
exactly like our Earth or our Moon, as large beads might be strung
close together upon a wire.
How many worlds, the size of our Earth, do you think you would need to
reach all through the Sun from side to side? And how many worlds the
size of our Moon?
You would want more than one hundred Earths. And if, instead of Earths,
you chose to string Moons on the big needle, you would need more than
four hundred Moons.
These would not fill up the enormous hollow ball. They would only reach
through in one straight line from side to side, showing the _diameter_
of the Sun.
Now try again to think of the Moon as a tiny ball, softly bright on one
side, only one inch through; and of the Earth as another ball, shining
on one side, four inches through. Think of them, if you like, as a
large grape and a small cocoa-nut made of silver.
Then take the same measure for the Sun, letting one little inch do duty
always for two thousand miles. The Sun must dwindle and dwindle in size
till every two thousand miles in him has become a single inch.
We shall then have a huge ball, or balloon, four hundred and twenty-six
inches, or some _thirty-five feet_, through, from side to side.
Thirty-five feet is a great deal more than four inches. _One_ foot is
twelve inches long.
You have seen many a tall man close upon six feet in height. This
balloon, to picture the Sun, must be so large that six tall men might
be put inside it, one upon the head of another. The whole string of six
tall men would about make the through measure of the globe.
So we have a Moon the size of a large grape, an Earth the size of
a small cocoa-nut, and a Sun the size of a balloon big enough to
contain six men in a long row, one upon another. The two little balls
would shine softly, on one side only; but the large balloon should be
exceedingly brilliant and dazzling all round.
If the Moon is so tiny and the Sun is so huge, how is it that they seem
to be the same size in our sky?
Because of the very great difference in their distance from us. The
Moon is near; the Sun is far away.
Suppose you are looking at a man near at hand and at a house miles
away; which seems to you the bigger? Of course the man, because he is
so close. Yet really the house is much the larger of the two.
The Moon is only about two hundred and forty thousand miles off; but
the Sun is about ninety-two millions of miles away.
Think what a difference! Two hundred and forty thousands are only a
small part of a single million; for a million is a thousand thousands.
If you have one thousand beads in a heap, you would need one thousand
of those heaps to make a million beads. And when you get to the idea
of what is meant by a million, you have to remember that the Sun’s
distance is ninety-two times _that_ number of miles.
After all, we cannot comprehend these figures; they are too
bewildering. We may talk of thousands and millions of miles, but we do
not _see_ them in our minds.
The chief thing to do is to gain some notion of one distance side by
side with another: and here the three balls all help us again.
Picture to yourself the tiny Moon-ball, as big as a large grape, and
the Earth-ball, as big as a small cocoa-nut; and in your mind put the
two _ten feet_ apart. There you have the sizes and the distance of the
Earth and the Moon brought down from thousands of miles to inches.
Then picture to yourself the Sun, as big as a balloon--the length of
six tall men through its middle--and in your mind put that balloon
_three quarters of a mile_ away from the small Earth and Moon. Somebody
will tell you of a house or a place about three-quarters of a mile away
from your house, if you ask.
Now do you see how great the difference is between the distance of the
Sun from us and the distance of the Moon?
Close upon four thousand feet off, instead of only ten feet off!
Almost thirteen hundred yards, instead of a little over three yards!
Ninety-two millions of miles, instead of two hundred and forty thousand
miles!
The _kind_ or _quantity_ of difference between the two is the same,
whether we reckon it in inches or feet, in yards or miles, in hundreds,
or thousands, or millions of miles.
The Moon and Sun are quite unlike in their way of shining.
Our little Moon has no brightness of her own. She only shines when and
where the Sun shines upon her.
But the radiance of the Sun is his own; it is a part of himself. He
shines because it is _in_ him to shine; it is his nature to shine. He
is brilliant all round, not on one side only. If the Sun were destroyed
the Moon would shine no longer. But if the Moon and the Earth and
all the Planets came to an end it would make no difference in the
brightness of the Sun.
The Sun’s shining is like the shining of the Stars, not like that of
the Earth and the Moon: for the Sun himself is a Star; one Star among
millions of Stars. He only looks so much larger and brighter than other
Stars because he is so much nearer than they are.
Our Earth and Moon are not stars; they are planets, or worlds,
travelling round the Sun, and belonging to him. They are not hot
bodies, glowing with their own light; but cool and dark bodies,
bright only when the Sun shines on them. Moonlight, and also
Earthlight--which we, living on the Earth, cannot see--are both really
reflected Sunlight.
There are other planets also, besides the Earth and the Moon, belonging
to the Sun: such as Venus, and Mars, and Jupiter. None of these planets
are Stars. They are all Worlds.
QUESTIONS.
1. What shape is the Sun?
Like the Earth and the Moon, a globe or sphere in shape.
2. What is the Sun’s diameter?
The Sun is about 850,000 miles through.
3. Why do the Sun and Moon seem about the same size in our sky?
Because the Moon is very near, and the Sun very distant.
4. How far off is the Sun?
About 92 millions of miles.
5. What would be the sizes of these three globes, if we let one inch
stand for 2,000 miles?
The Moon would be a ball one inch in diameter; the Earth a ball four
inches in diameter; the Sun a ball thirty-five feet in diameter.
6. What would be their distances, brought down thus?
The Moon would be about ten feet off from the Earth, and the Sun would
be about three-quarters of a mile from them both.
7. How many thousands of miles make a million miles?
A thousand thousands.
8. How does the Moon shine?
By reflecting Sunlight.
9. How does the Sun shine?
By his own brightness.
10. Which part of Moon and Sun are bright?
The Moon, like the Earth, is bright only on that side which faces the
Sun; but the Sun is brilliant all round.
11. Is the Sun a World?
No, the Sun is a Star.
12. Are the Planets Stars?
No; the Planets, like Earth and Moon, are Worlds.