All the planets and their satellites move in ellipses of such small eccentricity that they are nearly circles.

All the planets move in the same direction and nearly in the same plane.

The movements of the satellites are in the same direction as those of the planets.

The movements of rotation of the sun, of the planets, and the satellites, are in the same direction as their orbital motions, and in planes little different.
It is impossible that so many coincidences could be the result of chance! Is it not plain that there must have been a common tie among all these bodies, that they are only parts of what must once have been a single mass?
But if we admit that the substance of which the solar system consists once existed in a nebulous condition, and was in rotation, all the above peculiarities follow as necessary mechanical consequences.

Nay, more, the formation of planets, the formation of satellites and of asteroids, is accounted for.