THE NEW COSMOLOGY 



between them and the earth. This proves sufficiently 

 that their centre belongs to the sun and is the same about 

 which the orbits of Venus and Mercury circle. Since, 

 however, all have one centre, it is necessary for the space 

 intervening between the orbits of Venus and Mars to 

 include the earth with her accompanying moon and all 

 that is beneath the moon ; for the moon, which stands 

 unquestionably nearest the earth, can in no way be 

 separated from her, especially as there is sufficient 

 room for the moon in the aforesaid space. Hence we 

 do not hesitate to claim that the whole system, which 

 includes the moon with the earth for its centre, makes 

 the round of that great circle between the planets, in 

 yearly motion about the sun, and revolves about the 

 centre of the universe, in which the sun rests motion- 

 less, and that all which looks like motion in the sun is 

 explained by the motion of the earth. The extent of 

 the universe, however, is so great that, whereas the dis- 

 tance of the earth from the sun is considerable in com- 

 parison with the size of the other planetary orbits, it 

 disappears when compared with the sphere of the 

 fixed stars. I hold this to be more easily comprehen- 

 sible than when the mind is confused by an almost 

 endless number of circles, which is necessarily the case 

 with those who keep the earth in the middle of the uni- 

 verse. Although this may appear incomprehensible 

 and contrary to the opinion of many, I shall, if God 

 wills, make it clearer than the sun, at least to those who 

 are not ignorant of mathematics. 



" The order of the spheres is as follows : The first and 

 lightest of all the spheres is that of the fixed stars, 

 which includes itself and all others, and hence is 



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