464 



GENERAL SCIENCE 



again into the great heated mass of material of which the sun 

 is composed. The cooling of these oxides makes them appear 

 dark. 



The Moon. The next body of interest to us in the sky is the 

 moon. Many superstitions and erroneous beliefs have come down 

 to us regarding the moon. Some people have believed that the 



moon controls the weather; 

 this, of course, is absurd. The 

 moon is about 239,000 miles 

 from the earth. The moon, 

 unlike our earth, turns on its 

 axis once in 27^ days, which 

 means that daylight on the 

 moon is as long as 14 of our 

 days, and that a night is of equal 

 duration. 



When the moon comes up 

 above the horizon it appears 

 to be considerably larger than 

 later in the evening. There 

 are two reasons for this: 



1. We are looking through 

 a greater amount of atmos- 

 phere. This magnifies the size 

 of the moon. 



2. We are comparing the 

 size of the moon with objects 

 on the horizon. 



After it has risen in the sky there is nothing with which to make 

 comparison. 



No one has ever seen the other side of the moon since it revolves 

 around the earth with the same side toward us. The ancients 

 early noticed that the moon did not rise at the same time every 

 night, and at certain times did not appear during the night at 

 all but during the day. They observed that the moon rose 1 hour 

 later (53 minutes) each night. 



The light of the full moon is only about eoo^oo that of the sun. 



FIG. 353a. Mountainous surface of the 

 moon. 



