SECTION G 

 THE HEAVENLY BODIES 



CHAPTER XXXII 



THE EARTH AS A PART OF THE SOLAR SYSTEM 



1. In what ways are the sun and moon dif- 

 ferent ? 



2. How do stars differ from planets? 



Solar system. The earth is but one of many heavenly 

 bodies scattered through space. In this chapter we will 

 try to obtain some idea of these bodies and of their relation 

 to the earth. The earth, the other planets, the moon, and 

 the sun are included together in what is called the solar 

 system. The center of this system is the sun. Revolving 

 around this sun are the planets situated at varying distances 

 from the common center. Some of these, such as Mercury 

 and Venus, are nearer the sun than is the earth ; others, 

 such as Mars, Saturn, Uranus, and Neptune, are farther 

 away than the earth. 



The positions of these planets may be illustrated by 

 means of circles, as shown in figure 206. The dot in the 

 center represents the sun. The circles represent the orbits 

 of the various planets. If one inch be taken to represent 

 the distance of the earth from the sun, then to represent the 

 orbit of the moon, a circle should be drawn around the earth 

 at a distance of one four-hundredth of an inch from it. 

 This is too small to be shown on this diagram. All these 



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