THE SOLAR SYSTEM 5 



seen that they are continually changing their places among; 

 the stars, whereas the positions of the stars do not appear 

 to change relatively to one another. 



These bright, steady-shining points are called planets, 

 from the Greek word meaning wanderer, and they belong to 



PART OF THE MILKY WAY 



There are hundreds of millions of stars in the Milky Way, so thickly strewn 

 that they appear to the eye as an irregular stream of light across the 

 sky. The plate for this photograph was exposed ten hours and a 

 quarter. 



a family of heavenly bodies, of which the earth is one, that 

 make regular circuits about the sun. This family of the 

 sun is called the solar system. The planets are by far the 

 nearest of all star like bodies, although the earth's nearest 

 neighbor, the planet Venus, never comes nearer than 23 

 millions of miles. The most distant planet, Neptune, is 



