Page:Popular Science Monthly Volume 13.djvu/353

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ON THE FORMATION OF NEBULÆ.
359

ON THE FORMATION OF NEBULÆ.

By WILLIAM M. DAVIS, Esq.

THE close proximity of the satellites of Mars to their primary has led me to investigate the lesson taught by them and other satellites of short periods.

This investigation has enabled me to demonstrate:

I. That the nebular hypothesis fails to account for the present condition of the solar system, without the additional hypothesis of a resisting medium in space.

II. It has enabled me to show, also, that, although this medium tends to bring the solar and all other systems to a state of quiescence, it has no such tendency on the material universe as a whole, provided that the ponderable matter thereof be of infinite extent. If, however, the ponderable matter—as distinguished from the ether—be of finite extent, it should come to rest, as will be shown in the sequel.

The first proposition will be established by taking the first satellite of Mars as an example, and proving that it must have been at least fifteen or twenty times as far as it now is from its primary when it was able to take on the globular form from the nebulous ring out of which it was made. This being established, it follows, as a necessity, that its orbit must have contracted into its present dimensions since it was thus formed; and the satellite during this time has condensed into its present condition.

As the same cause which contracts the orbits of the satellites should produce a like result upon those of the planets, it follows that they, too, must have been farther away from the centre of the system than they now are, when they took on the globular form from their nebulous rings.

The hypothesis of a resisting medium has been adopted to account for this contraction of orbits, as no other hypothesis seems competent to do so.

That this satellite of Mars and others in our system were much farther away from their primaries than they now are, will be proved, by proving that, if a nebulous satellite revolved around any primary in the short period in which most of the solid ones now do, the tidal energy—or tendency to elongation and disruption—which would, in that case, be generated on its opposite sides by such rapid revolution, would be sufficient to tear it into atoms. These atoms would be distributed around the primary in the form of a nebulous ring, which ring would be in a state of stable equilibrium, and therefore could not be reconverted into the globular form.

Permit me, then, to bring forward some imaginary experiments, for the purpose of illustrating certain dynamical principles (and methods) to be employed in proving the fact just stated.