THE EARTH 3 



The largest of the planets is Jupiter, which is more 

 than three hundred and seventeen times as large as the 

 earth. Saturn is next smaller, and then follow in order 

 Neptune, Uranus, Earth, Venus, Mars, and Mercury. 



The brightest of the planets are Venus, Mars, Jupiter, 

 and Saturn, and they are plainly visible at certain periods. 



Neptune 



FIG. . 1. The Sun and Planets. 



It is very seldom that all four are seen at the same time 

 in any evening, but two are often in the sky together 

 and sometimes three. Part of the time they are morn- 

 ing stars and at other times evening stars. The other 

 three planets Mercury, Uranus, and Neptune can- 

 not be seen easily without a telescope. 



Satellites or Moons. Not only do the planets revolve 

 around the sun, but each of them, except Mercury and 



