Page:Popular Science Monthly Volume 15.djvu/19

Rh both bodies were ten times as great, the conflict of the invading mass would be about 100,000 times as violent, and a correspondingly greater amount of energy would be converted into electric, magnetic, and calorific forces. Accordingly, great suns, in passing through their most terrific scenes, call forth a world-making power of the greatest vigor; and will not only give birth to larger spheres, but also send them forth in wider orbits.

But the size and mass which a world attains must depend mainly on the numbers of meteors and comets frequenting the solar dominions while it was in the course of formation. At the birth of Jupiter this vagrant matter was more than usually abundant, and it served to give the planet a predominance over the other members of the solar family. It is very probable that the minute and the rare tenants of space are very numerous in the Milky Way; but this abundance of chaotic material, though calculated to increase the size of worlds, must shorten their term of existence, as the increase which suns obtain in mass and attraction would have the same effect as a resisting medium in abridging the lives of their planets. Events involving the mortality of worlds would thus become more frequent; and it is worthy of remark that it was in or near this part of our universe that most of the temporary stars have sent forth their sudden display of brilliancy. In such a region a planet of large size in closing its career by incorporating with a sun would be attended by an electro-magnetic energy sufficient to give birth to another planetary member of considerable magnitude on the outer zone of the solar system, so that the existence of worlds would not be wholly dependent on the union of double suns.

But even in our own part of the celestial domain there are to be found evident marks of the occurrence of one of those stupendous events to which I have ascribed the appearance of temporary stars, and which are so intimately connected with the birth and death of worlds. On comparing the observations of Carrington and Spoerer with those of Vogel and Young, it appears that for the sun's equatorial zone the time of rotation is scarcely twenty-two days, while it is nearly four weeks for the parallel of fifty degrees. So great and unexpected a difference in the diurnal motion of its parts proves that our central luminary must have at some past time received a large mass, which had a direct motion over his equator, and was finally precipitated to his surface. Whether the incorporating mass was a planet, or the last remains of the great companion which cooperated in giving being to the solar family, the effects deserve attention so far as they show the present working of a power which has been long in a declining condition. The movement of one zone of matter over another having a different velocity of rotation must be a source of solar magnetism, and this force may be therefore regarded as much weaker than it was a million years ago, but much stronger than it will be in very distant future ages.

Yet, even in its reduced state, this magnetic agency is not without