Page:The evolution of worlds - Lowell.djvu/145

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THE OUTER PLANETS
113

in the plane in which either particle was previously moving, both will be thrown more or less out of the general plane of their fellows, and the ring at that point, even if originally flat, will not remain so. For the ring, though very narrow relatively, has a real thickness, quite sufficient for slantwise collision, if the bodies impinge. Now the knots or beads on the rings appeared exactly inside the points where the satellites' disturbing action is greatest, or, in other words, in precisely their theoretic place. We can hardly doubt that such, then, was their origin.[1]

The result must be gradually to force the particles as a rule nearer the planet, until they fall upon its surface, while a few are forced out to where they may coalesce into a satellite,—a result foreseen long ago by Maxwell. It is this process which in the knots we are actually witnessing take place, and which, like the corona about

  1. Paper by the writer in the Phil. Mag., April, 1908.