THE BIRTH OP THE SUN AND PLANETS 15 



body was at least 500 billion miles away from the earth 

 that is to say, so far away that it would take 1,500 

 million years to count the miles, at one mile per second 

 we begin to realise what this means. It means a 

 sudden conflagration of a most stupendous character; 

 you have some idea of it if you imagine a sun to be 

 made of petroleum and suddenly P-ed. Astronomers 

 watched it with great curiosity for months. The blaze 

 slowed down, flickered and flared, and at last went again 

 below the range of visibility. But all during the winter 

 a little cloud of luminous matter was creeping out from 

 either side of the point of light. At the end of six 

 months the cloud was " no bigger than a man's hand " 

 in the large telescope very much smaller, in fact but 

 astronomers knew what that meant, having regard to the 

 distance. It was several billion miles in extent: its 

 "creeping" meant a motion of more than 100,000 miles 

 a second. A new nebula was given to the universe if 

 we may set aside the opinion of a few that it was the 

 sudden lighting-up of a dark nebula. I said that a nebula 

 was formed under our eyes in 1901. It really happened 

 under the eyes, or over the head, of Napoleon I ; but the 

 conflagration was so far away that, though the waves of 

 light were hurrying with the message across space at the 

 speed of 186,000 miles a second, it took them 99 years 

 at least to bring it to the earth. 



What was the cause of the catastrophe, and therefore 

 of the birth of the nebula? If we know this we have a 

 sufficient suggestion to offer to those persistent people 

 who refuse to go on until they know where our nebula 

 came from. We do not know definitely, but we know 

 several ways in which it might arise. Many observers 

 thought Sir R. Ball and others still think that two 

 dead stars came into collision. If such a thing even a 

 "grazing" or partial collision did happen, it would be 



