THE MOON, PLANETS, AND COMETS 



245 



which is received from the sun. This conclusion is quite 

 erroneous, for the brightest full-moon light is only about 

 TinfW of the brightness of sunlight. Taking the whole 

 month into consideration, the amount of light and heat re- 

 ceived from the sun is about 2,500,000 times the amount 

 received from the moon ; or, in other words, the earth receives 

 as much light and heat 

 from the sun in thir- 

 teen seconds as it re- 

 ceives from the moon 

 during a whole year. 

 It follows from this 

 that it is not reasona- 

 ble to suppose that the 

 moon has any impor- 

 tant climatic effects 

 on the earth. This con- 

 clusion is confirmed 

 by observations which 

 have been made by the 

 weather bureaus of 



, FIG. 123. New moon 



various countries for 



. The moon in its second day, also the old moon in 



many years. It IS found dimoutline. Photograph by the Yerkes Observatory 



from the records that 



there is no certain relationship between the phases of the 



moon and the characteristics of the weather. 



251. Distance and size of the moon. It is commonly sup- 

 posed that it is impossible to measure with certainty the 

 distances to the heavenly bodies and that what astronomers 

 say about them is merely speculation. This opinion is errone- 

 ous, for these distances are measured in the same sense that 

 distances are measured on the surface of the earth, and the 

 percentage of error is very small except for the stars. The 

 essence of the method of measurement is very easy to under- 

 stand. It depends upon the fact that the moon appears in 



