X THE STARRY HEAVENS 389 



know for certain, Mercury is the one nearest 

 to the Sun, its average distance being 

 36,000,000 miles. It is much smaller than 

 the Earth, its weight being only about ^th 



'ee^e^-.. 



-■'Neptune 



. -~,Uranus 



Fig. 52. — Relative distances of the Planets from the Sun. 



of ours. Mercury is a shy though beautiful 

 object, for being so near the Sun it is not 

 easily visible ; it may, however, generally be 

 seen at some time or other during the year as 

 a morning or evening star. 



