FREE BOOKS

Author's List




PREV.   NEXT  
|<   83   84   85   86   87   88   89   90   91   92   93   94   95   96   97   98   99   100   101   102   103   104   105   106   107  
108   109   110   111   112   113   114   115   116   117   118   119   120   121   122   123   124   125   126   127   128   129   130   131   132   >>   >|  
comparable with the entire diameter of the earth--existing between its equatorial and its polar diameter, the former being 75,000 and the latter 68,000 miles. We found the density of Jupiter astonishingly slight, but that of Saturn is slighter still. Jupiter would sink if thrown into water, but Saturn would actually float, if not "like a cork," yet quite as buoyantly as many kinds of wood, for its mean density is only three quarters that of water, or one eighth of the earth's. In fact, there is no known planet whose density is so slight as Saturn's. Thus it happens that, notwithstanding its vast size and mass, the force of gravity upon Saturn is nearly the same as upon our globe. Upon visiting Venus we should find ourselves weighing a little less than at home, and upon visiting Saturn a little more, but in neither case would the difference be very important. If the relative weight of bodies on the surfaces of planets formed the sole test of their habitability, Venus and Saturn would both rank with the earth as suitable abodes for men. But the exceedingly slight density of Saturn seems to be most reasonably accounted for on the supposition that, like Jupiter, it is in a vaporous condition, still very hot within--although but slightly, if at all, incandescent at the surface--and, therefore, unsuited to contain life. It is hardly worth while to speculate about any solid nucleus within, because, even if such a thing were possible, or probable, it must lie forever hidden from our eyes. But if we accept the theory that Saturn is in an early formative stage, and that, millions of years hence, it may become an incrusted and habitable globe, we shall, at least, follow the analogy of what we believe to have been the history of the earth, except that Saturn's immense distance from the sun will always prevent it from receiving an amount of solar radiation consistent with our ideas of what is required by a living world. Of course, since one can imagine what he chooses, it is possible to suppose inhabitants suited to existence in a world composed only of whirling clouds, and a poet with the imagination of a Milton might give us very imposing and stirring images of such creatures and their chaotic surroundings, but fancies like these can have no basis in human experience, and consequently can make no claim upon scientific recognition. Or, as an alternative, it might be assumed that Saturn is composed of lighter elements and mate
PREV.   NEXT  
|<   83   84   85   86   87   88   89   90   91   92   93   94   95   96   97   98   99   100   101   102   103   104   105   106   107  
108   109   110   111   112   113   114   115   116   117   118   119   120   121   122   123   124   125   126   127   128   129   130   131   132   >>   >|  



Top keywords:

Saturn

 

density

 

Jupiter

 
slight
 

composed

 

visiting

 

diameter

 

equatorial

 
analogy
 

habitable


follow

 
prevent
 

receiving

 
amount
 

incrusted

 

immense

 

distance

 
history
 

probable

 

forever


hidden

 
millions
 

radiation

 

formative

 

accept

 

theory

 
required
 

fancies

 
surroundings
 

chaotic


imposing

 

stirring

 

images

 

creatures

 
experience
 
assumed
 
lighter
 

elements

 

alternative

 

scientific


recognition

 

imagine

 
existing
 

nucleus

 

living

 

chooses

 
suppose
 

imagination

 

Milton

 

comparable