It will even happen, after not so very long a time, that one of those which have hitherto been continually in motion will finally coincide with the pole and stand still, but after a period of repose will again begin to move.

The other stars in the mean while, which unquestionably move, all have, as was said, a great circle for an orbit and keep this unchangeably.
"The improbability is further increased--this may be considered the sixth inconvenience--by the fact that it is impossible to conceive what degree of solidity those immense spheres must have, in the depths of which so many stars are fixed so enduringly that they are kept revolving evenly in spite of such difference of motion without changing their respective positions.

Or if, according to the much more probable theory, the heavens are fluid, and every star describes an orbit of its own, according to what law then, or for what reason, are their orbits so arranged that, when looked at from the earth, they appear to be contained in one single sphere?
To attain this it seems to me much easier and more convenient to make them motionless instead of moving, just as the paving-stones on the market-place, for instance, remain in order more easily than the swarms of children running about on them.
"Finally, the seventh difficulty: If we attribute the daily rotation to the higher region of the heavens, we should have to endow it with force and power sufficient to carry with it the innumerable host of the fixed stars--every one a body of very great compass and much larger than the earth--and all the planets, although the latter, like the earth, move naturally in an opposite direction.

In the midst of all this the little earth, single and alone, would obstinately and wilfully withstand such force--a supposition which, it appears to me, has much against it.

I could also not explain why the earth, a freely poised body, balancing itself about its centre, and surrounded on all sides by a fluid medium, should not be affected by the universal rotation.