136 SCIENCE AND IMMORTALITY 



Venus both outstrip it ; and though Neptune does 

 not go nearly so fast, it describes an orbit twenty- 

 seven or twenty-eight times as long. 



A remarkable thing about the solar system is its 

 isolation in space. " Our solar system," says Sir 

 Robert Ball, " forms a little island group, situated 

 at almost incomprehensible distances from the 

 stars. The solar system is isolated from its 

 neighbours just as a rock a few yards square in 

 the middle of the Atlantic would be isolated from 

 the coasts of Europe and America." 



Yet the solar system is not fixed like a rock : 

 the Sun and its retinue of planets are constantly 

 moving through space to a certain point in the 

 constellation of Hercules. Every two days it is 

 about a million miles nearer this point, and at 

 the present rate of progress we shall reach the 

 constellation of Hercules in about a million years. 



So much for the Earth in its social relations ; 

 we will now consider for a moment its individual 

 characters and its life history. When was it 

 born ? What has it done since birth ? How old 

 is it ? How was it shapen ? What is to become 

 of it ? 



The manner of its birth we have already 

 considered ; but when was it born ? We do not 

 now believe that it was born in the year 4004 

 B.C., but the date of its birth we do not know. 



