CHAPTER XXI 

 THE SUN AND OTHER STARS 



266. Questions for Discussion. 1. The earth is so far from the sun 

 (92,900,000 miles) that we cannot understand what the enormous 

 distance really means. Can you devise a demonstration which will 

 give a better sense of this distance? 2. The diameter of the sun is 

 866,000 miles. How many earths side by side would be required to 

 extend directly through the sun? 3. Since the earth receives but a 

 very small part of the light and heat which is radiated from the sun, 

 what becomes of the rest of the radiated light and heat? 4. What is 

 a spectroscope? How does it enable astronomers to determine the 

 nature of the sun and stars? 5. Are some of the stars like our sun 

 in the sense that they are centers of great solar systems? 6. Are there 

 stars which are. larger and which give off more light than our sun ? 



7. Why do we not receive more light and heat from the larger stars? 



8. By use of the text discussions and a star chart see if you can locate 

 the following : the Big Dipper, the Pleiades, the North Star, Cassiopeia, 

 Pegasus, Orion, the Milky Way. 



267. Distance and size of the sun. When we are told that 

 the average distance of the sun from the earth is 92,900,000 

 miles, we at once realize that we have no appreciation of the 

 meaning of such a distance. It may help if we interpret in 

 terms of some of the things we do or see others do. For 

 example, if we could ride without stopping from the earth 

 to the sun in an aeroplane which travels at the rate of 

 100 miles an hour, it would take one hundred and six years 

 to reach the sun. This means that if a very speedy aeroplane 

 could make a continuous trip from the earth to the sun, it 

 would require for the trip something like the whole amount 

 of time that has passed since your great-grandparents were 

 little children. If an athlete who can run 100 yards in ten 



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