The Earth’s Satellite

The seasons are fixed by wisdom divine,

The slow changing moon shows forth God’s design;

The sun in his circuit his Maker obeys,

And running his journey hastes not nor delays.


In the last issue of “The Beacon Lights” various aspects of the moon were discussed.  Perhaps, other question may have arisen; for example, “Why does the moon appear larger when it rises than when it is overhead?”  Actually, it is further away from us when it makes its appearance.  A current explanation is that it appears greater in size at the horizon because it is in juxtaposition with trees or buildings with which its size can be compared, while when viewing it overhead, there is nothing visible near it only the endless expanse of the heavens.  According to recent reports Harvard psychologists discovered that the moon appears larger overhead than at the horizon when one is in a reclining position and visa versa when one stands upright.  This effect, they claim, is due to a very peculiar property of the brain and eye, which makes objects directly in front of one appear larger than when on an angle.  Try both—the upright and reclining positions the next time you observe the full moon and note the difference in size.

Frequently the question arises, “Why does the moon change its shape?”  Surely, we all have observed at one time different phases of the moon—new moon, full moon, quarter moon, etc.  The continuous change in the moon’s appearance to us who inhabit the earth is due to the moon’s revolution around the earth.  Perhaps, you recall that the moon does not give light as the sun and stars do, but only reflects light.  It is a spherical mirror, only one half of which is exposed to the sun’s rays at any one time and, consequently, the other half is continuous darkness.  When we observe the full moon, we see the complete half which is exposed to the sun.  The new moon, of course, is invisible—the other half not exposed to the sun.  When the moon is between and earth and the sun, we see the “new moon” phase.  It is invisible because we see the unlighted side.  However, when the moon is on the reverse side of the earth, we have a “full moon,” which reflects all the rays toward us.  We see the moon pass thru a continuous cycle of phases (faces)—commencing with the new moon, crescent, first quarter, gibbous (meaning hunched), full moon, gibbous, last quarter, crescent and the new moon.  This cycle requires approximately 29 days and 13 hours.  When it increases in size it is called a “waxing moon,” and when it recedes it is called a “waning moon.”

A third question sometimes asked is: “What effect has the moon upon the earth?”  The most striking, perhaps, is the relationship between the moon and the tides.  The attraction of the moon is chiefly responsible for the rising and falling of tides.  Water is moveable, whereas land is stationary; hence, although the force of attraction is exerted on both, only the water rises.  Not only the water on the side nearest the moon rises, but also the water on the opposite side, while the two sides at right angles experience a low tide.  Every 12 hours and 25 minutes there is a high tide, in other words, two high and two low tides per day.

Tides are not only interesting phenomena, but of great significance to the seafaring people.  In the Bay of Fundy off the coast of Newfoundland, the difference in water level between high tide and low tide varies as much as 60 feet per day.  However, on most of the Atlantic Coast the rise is only one to three feet, depending on the ocean bed and the irregularity of the coastline.  Mariner’s Charts have been provided which list the time and rise in tides for every day of the year for all important harbors.

In the Old Testament the new moon was relied upon to mark off the months of the year and aided in determining the feasts.  During the days of the patriarchs many of the heathen nations worshipped the moon.  In Egypt it was customary to sacrifice a pig at full moon.  During these times it was also a common practice to predict important political events on the basis of the moon’s rising or appearance.

Since the months were determined by the moon and began at the time of the new moon, the Israelites set aside this day as a holy day.  Watchmen were assigned to the heights around Jerusalem, and when sufficient evidence had been gathered that it was “new moon” the Sanhedrin pronounced the word of consecration.  If cloudy weather prevented careful observation, the thirtieth day after the previous new moon was celebrated.  A beacon fire was then lit on the Mount of Olives, which was followed by similar fires built on other high mountains throughout the land.  Thus, the entire population would know when a new month had begun.  Later the appearance of the new moon was announced by messengers, because the Samaritans started fires prematurely to purposely upset the Jewish time table.  Thus we can realize that from the beginning of time, the moon has played an important role in the history of mankind.


The sun with royal splendor

Goes forth to chant Thy praise,

And moonbeams soft and tender

Their gentler anthem raise;

O’er every tribe and nation

The music strange is poured,

The song of all creation

To Thee, creation’s Lord.”