54 DISTANCE OF FIXED STARS. SECT. VII. 



of the periodic times of any two planets being as the cubes of 

 their mean distances from the sun, their absolute distances in 

 miles are easily found (N. 134). This law is very remarkable, 

 in thus uniting all the bodies of the system, and extending to 

 the satellites as well as the planets. 



Far as the earth seems to be from the sun, Uranus is no less 

 than nineteen, and Neptune thirty times farther. Situate on the 

 verge of the system, the sun must appear from Uranus not much 

 larger than Venus does to us, and from Neptune as a star of the 

 fifth magnitude. The earth cannot even be visible as a telescopic 

 object to a body so remote as either Uranus or Neptune. Yet man, 

 the inhabitant of the earth, soars beyond the vast dimensions of the 

 system to which his planet belongs, and assumes the diameter of 

 its orbit as the base of a triangle whose apex extends to the stars. 



Sublime as the idea is, this assumption proves ineffectual, 

 except in a very few cases ; for the apparent places of the fixed 

 stars are not sensibly changed by the earth's annual revolution. 

 With the aid derived from the refinements of modern astronomy, 

 and of the most perfect instruments, a sensible parallax has been 

 detected only in a very few of these remote suns, a Centauri 

 has a parallax of one second of space, therefore it is the nearest 

 known star, and yet it is more than two hundred thousand times 

 farther from us than the sun is. At such a distance not only 

 the terrestrial orbit shrinks to a point, but the whole solar system, 

 seen in the focus of the most powerful telescope, might be eclipsed 

 by the thickness of a spider's thread. Light, flying at the rate of 

 190,000 miles in a second, would take more than three years to 

 travel over that space. One of the nearest stars may therefore 

 have been kindled or extinguished more than three years before 

 we could have been aware of so mighty an event. But this 

 distance must be small when compared with that of the most 

 remote of the bodies which are visible in the heavens. The fixed 

 stars are undoubtedly luminous like the sun: it is therefore 

 probable that they are not nearer to one another than the sun is 

 to the nearest of them. In the milky way and the other starry 

 nebulas, some of the stars that seem to us to be close to others 

 may be far behind them in the boundless depth of space ; nay, 

 may be rationally supposed to be situate many thousand times 

 farther off. Light would therefore require thousands of years to 

 come to the earth from those myriads of suns of which our own 

 is but " the remote companion." 



