SHOOTING STARS 405 



Some of these planets, such as the Earth, Jupiter, and 

 Mars, have moons which in turn revolve around them. 

 These simply reflect sunlight, and do not give any light 

 themselves. All of these moons, planets, and the sun to- 

 gether make up a small heavenly group which we call the 

 Solar System. You may think the word small used inad- 

 visedly. It is a large 

 system when com- 

 pared with the size 

 of the earth, but 

 compared with the 

 size of the other 

 systems and the vast 

 expanse of the uni- 

 verse which we look 

 into on a clear night, 

 it is absolutely insig- 

 nificant. It is rea- 

 sonable to believe 

 that each of the mil - 



Relative sizes of planets, sun, and moon. 



lions of stars in the 



sky has its own family of planets and moons, just as our 

 sun has, but since these are so far away and have no light 

 of their own, they are invisible to us. 



Shooting stars. We have all seen the burst of stars 

 which comes from the explosion of a beautiful rocket, 

 and indeed we have sometimes mistaken the light from 

 a small toy balloon for that of a star. It is not strange 

 that some people have been deceived by so-called " shoot- 

 ing stars " and thought that stars were actually falling. 

 Such, however, is not the case. There are throughout 

 the space which surrounds the earth and other planets 



