Rensselaer Union, Volume 2, Number 45, Rensselaer, Jasper County, 4 August 1870 — Spots on the Sun. [ARTICLE]

Spots on the Sun.

Our readers are all familiar with the existence of spots on the surface of the sun, and their variation in number and size from one time to another. Tho exigence of these spots, and the question of their periodicity, have been investigated by astronomers for some years past, and several successive periods of appearance and disappearance have been established quite satisfactorily. —• — The principal of these are. an elevenyear period, a fifty-six year period, a two-hundred-and-tWenty-three-day period, a twenty seven day period, and a five-hun-dred-and-eighty-fottr day period. Among other causes for the occurrence of these spots, and their periodicity, that of planetary disturbance has been warmly urged, although the precise connection between the position of the planets and the solar spots is not ’yet established. Professor Kirkwood, an eminent American astronomer, has lately published an elaborate memoir, in which, as a summary of his investigations, he states that the fact of the connection between the changes of the solar spots and the position of certain planets is unquestionable, and that a particular region of the solar surface is more susceptible than others to planetary disturbances, these occurring, as they do, between definite parallels of latitude, the number being greater in the northern than the southern hemisphere of the sun. He also announces that of the cycles of variation above mentioned, that of eleven years has been traced to the influence of Mercury; and that the marked irregularity of this period, from 1822 to 1867, is equally dufe to the disturbing action of Venus also; and finally, that tho fifty-six-year cycle is determined by joint action of Mercury and the earth. —Hirper's Magazine.