Our Earth and Its Fellow Planets [ 403 



SUN'S RAYS 



THE MOON IS ECLIPSED WHEN COVERED BY THE EARTH'S SHADOW 



An eclipse of the moon does not occur each time the moon makes its circle around 

 the earth; usually the sun passes above or below the earth's tapering shadow, 

 which is nearly a million miles long! But when sun, earth, and moon are in line, 

 the earth blots out the sun's rays. However, some of these rays are bent in passing 

 through the earth's atmosphere enough to make the moon faintly visible, with 

 a coppery tint. Astronomers predict these eclipses with extraordinary precision. 



In its journey around the earth, the moon usually passes once a 

 month either below or above the shadow cast from the darkened 

 side of the earth. But sometimes the moon passes through this 

 earth shadow and then becomes nearly invisible eclipsed. A whole 

 year may go by without a lunar eclipse; in another year there may 

 be as many as three eclipses. 



On some of these occasions the moon passes through the edge of 

 the shadow and only part of it is darkened; at other times it is 

 completely in the shadow. But even during a total eclipse the 

 moon does not entirely disappear from view it only dims and 

 changes color. The point is that it does not completely lose all 

 sunlight. Some of that light is refracted (bent) by the earth's 

 atmosphere; and because red, orange, and yellow pass most easily 

 through the atmosphere, the moon appears a deep copper color 

 when it is eclipsed. 



Astronomers can predict eclipses. Newspapers and almanacs tell 

 when they will occur, and from what places they may be seen. 



