The Sun 215 



miles, or nearly no times the earth's diameter, and the 

 area of its surface is about 12,000 times the area of the 

 surface of the earth. Can you think of anything so 

 immense ? Imagine the surface of the sun to be divided 

 into states each the size of Ohio or Virginia. Now 

 imagine a giant who at one stride could step from Boston 

 to Albany ; a second stride carrying him to Harrisburg, 

 a third to Columbus, a fourth to Indianapolis, and so 

 on. Let this giant begin visiting the states on the sun, 

 spending but a minute in each state and never visiting 

 the same one twice. If the giant begins at noon to- 

 day, making a visit of a minute to each state, how 

 long would it take him to visit all the states? Cer- 

 tainly 60 minutes would not suffice ; would 60 years ? 

 The twentieth century would have passed before he 

 could complete the task. You can readily calculate 

 how long it would take him to make all his visits if 

 you call the area of Ohio or Virginia 40,000 square 

 miles and the area of the earth 200,000,000 square 

 miles. 



How we know the size of distant objects. Just as 

 surveyors can calculate accurately the distance of a 

 tree by sighting at it from the ends of a line, so they 

 can determine also the height of a tower without going 

 up on it, by measuring the angle formed by two lines 

 directed, one toward its top, the other toward its base. 

 They must know also the distance of the tower from 

 the place from which they are viewing it. From Figure 

 133 it is obvious that the larger the object, the larger 

 will be the angle made by the lines from the two ends 

 of it. 



