THE SIDEREAL UNIVERSE. 713 



time when the whole will be annihilated in one common 

 wreck. The earth, in fact, after its period of incandescence 

 and of life, will, in cooling, pass successively through the dif- 

 ferent stages that the moon has already passed through, and 

 like it will one day be but a dead and frozen star. Every- 

 thing on its surface indicates that it is slowly undergoing 

 the same transformations as its satellite has undergone. It 

 has been calculated that Mh of the primitive ocean has 

 been already absorbed. The rest is doubtless destined to 



258. Comparative Dimensions of the Earth and Moon. 



rejoin this other portion, and this disappearance will take 

 place with the greater facility in proportion as the terres- 

 trial crust gets thicker by the effect of cooling ; for it has 

 been calculated that the earth could easily absorb fifty 

 oceans such as its own. 



The surface of the earth will then crack and split like 

 that of the moon at the present day, and its atmosphere 

 will rush into all the hollows, while long before that life will 

 be everywhere extinct ; so that the earth will be nothing 

 but a corpse. This strange catastrophe, however, which the 

 study of the moon indicates as inevitable, will take place 



