326 THE COMING OF MAN 



it, and all their moons about them, with the comets 

 coming from we know not whence, and after tm*n- 

 ing about the sun going back again to we know 

 not where? If you can do this, you will have a pic- 

 ture of our solar system as the men we have called 

 ''the searchers of the sky" see it. They think of 

 each star in the sky as the center of a system like 

 ours, moving as our sun moves. Is it not a vast and 

 wonderful universe in which we live? 



There is one star, the light of which fades and then 

 grows bright again. The Arabs long ago noticed 

 this, and named the star Algol, or the demon, be- 

 cause it seemed to wink at them. Now our as- 

 tronomers have found that that winking star is a 

 great sun, having a dark companion which revolves 

 around it, which cuts off part of its light from us. 

 Is that dark companion a world, moving around 

 the sun Algol? They think it is. So when Algol 

 seems to wink we are really seeing an eclipse of a 

 sun billions and billions of miles away. 



Among the stars are many that are double; that 

 is, instead of having a dark companion revolving 

 around them, as our world revolves around the sun, 

 two brilliant suns revolve around each other. What 

 would we do in summer if we had two suns in the 

 sky at once; or if one was in the sky by day and one 

 by night? We should have no night then, only a 

 short twilight twice a day; and how should we get 

 any rest or sleep? 



There is one of these star systems that to the 

 naked eye looks like a single star, but when seen 

 through a telescope it becomes three dazzUng suns, — 



