The Moon.
We have been told that the earth moves around the sun; does any planet move around the earth?
Yes; one planet moves around the earth.
What is that planet called?
It is called the Moon.
Fig. 3.
How often does the moon move around the earth?
Once in 27 d. 7 h. 43 min.
How long is the time from new moon to new moon again?
It is 29 d. 12 h. 44 min.
How often do we have new moon?
Once every 29 d. 12 h. 44 min.
What is the period from one new moon to another called?
It is called a Lunar month.
Are the lunar months all of the same length?
Yes; they are all of the same length.
Is there any other kind of month?
Yes; the Calendar month, as it stands in almanacs.
How many calendar months in a year?
There are twelve calendar months in a year.
Are the calendar months all of the same length?
No; some are thirty-one days long, some thirty days long, and one only twenty-eight days long.
When can we see the moon and stars best?
We can see them best when it is night.
From what do the moon and the other planets get their light?
They get their light from the sun.
What do they do with this light?
They reflect it.
How do we see them?
We see them by the light which they reflect.
Why cannot we see the moon and stars in the day-time?
Because the bright light of the sun hides their light.
Are there stars in every direction around the earth?
There are stars in every direction around the earth.
How do we know this?
Because stars may be seen from every part of the earth, when it is night.
Stars are in every direction around the earth, just as we may imagine the apples to be in every direction around a boy who has climbed into a tree full of that fruit.
What planet moves around the earth?
The moon moves around the earth.
Upon what part of the moon does the sun shine?
It shines upon the part towards the sun.
What does the moon do with the light which it receives from the sun?
The moon reflects the light received from the sun.
What is this reflected light called?
It is called moonlight when reflected from the moon.
Is that part of the moon on which the sun shines always towards the earth?
It is not always towards the earth.
When all of the moon on which the sun shines is towards the earth, how does the moon appear?
The moon appears to be round, and the whole of it seems to shine.
What is the moon then called?
It is called the Full Moon.
When no part of the moon on which the sun shines is towards the earth, how does the moon appear?
We do not see the moon at all, and we say there is no moon.
When a small part of the moon on which the sun shines is first turned towards the earth, what is it called?
It is called the New Moon.
Does the lighted part of the moon grow?
It seems to grow larger and larger, until the whole of the moon is lighted.
What is it then called?
It is then called the Full Moon.
What then takes place?
It seems to grow smaller and smaller, until the whole of the lighted part is gone.
Just before the last part is gone, what is it called?
It is called the Old Moon.
How long is it from one full moon to another full moon?
It is a lunar month.
How many full moons are there in a year?
There are thirteen full moons in a year.
Is the sun much larger than the moon?
The sun is many thousand times larger than the moon.
Why does the moon appear nearly as large as the sun?
Because it is so much nearer to us.
How far is the moon from the earth?
The moon is nearly 240,000 miles from the earth.
How far is the sun from the earth?
The sun is nearly 92,000,000 miles from the earth.
How long does it take the light of the sun to reach the earth?
It takes about eight minutes; therefore, the light of the sun must travel about twelve millions of miles in a minute, or two hundred thousand miles in a second of time. At this rate, the light would come from the moon to the earth in a little more than one second of time. It would take no longer for it to come than it does for the pulse to beat once, or the clock to make one tick.