478 GENERAL SCIENCE 



Movement of Stars. The stars seem always to be in the same 

 place, but in reality they are moving through space. Some of the stars 

 are traveling at enormous rates of speed, but they are so far away that 

 it would require years to detect any movement even if any star should 

 move one million miles per day. Our own star, the sun, is moving at 

 the rate of about 800 miles per minute. Scientists believe that stars 

 are all moving around some great center or centers. 



Nebulae. It is believed stars were made from vast gaseous bodies 

 called nebulae (meaning cloud). Nebulae are scattered throughout 

 the sky as masses of misty light moving through space like stars. They 

 are made up of glowing gases. Many of them are spiral or disc shaped. 



A nebula is a star in the process of forming. Only two or three 

 nebulae can be detected without a telescope. A blur of light surround- 

 ing the third star of Orion's sword is one of the nebulae which may be 

 observed with the naked eye. It is estimated that some of the nebulae 

 are so far away as to require 8,000,000 years for their light to reach us. 



Age of the Star. The color of the stars tells us something as to 

 the age of a star. When they are young stars, they are composed of 

 thin gas and shine wittua blue or white light. The star Rigel (re-gel), 

 below the belt of Orion, is a white star. 



The older the stars grow, the more solid they become, and the 

 more their light resembles that of the sun. As they grow older, they 

 also become red and more condensed. Betelgeuse in the constellation 

 of Orion is an example of a red sun. The colors of the stars vary. 

 Brilliant white, violet, blue, green, yellow, orange, fiery red and red 

 are some of the colors of the important stars. 



When the stars become very old they lose all color and heat. There 

 are many such stars, each representing a sun which has become cold and 

 desolate. 



Size of Stars. The stars vary in size. It is possible we do not see 

 the largest suns in the universe. Canopus (ca-no'-pus) is believed to 

 be larger and greater than Sirius (sir'-i-us). This star is in the southern 

 hemisphere, and looks only about half as bright as Sirius. Canopus' 

 distance from us is so unthinkably immense, and its size so far beyond 

 our estimate, we cannot begin to realize the wonder of this huge sun. 



Constellations and Important Stars. Ursa (ur'-sa) Major and Ursa 

 Minor, the Big Bear and Little Bear (Big Dipper and Little Dipper), 



