SUN-SPOTS.
Grave Doubts.
Herbert Spencer says: "At present none of the interpretations of the sun-spots can be regarded as established."
How numerous and how strange have been the theories promulgated as to the character of the manifestations called sun-spots. The dark spots in the sun have been supposed to be "solid bodies revolving very near its surface," "Smoke of volcanoes;" "Scum floating upon an ocean of fluid matter;" "Clouds;" "Opaque masses floating in the fluid matter of the sun, dipping down occasionally," "Fiery liquid surrounding the sun which, by its ebbing and flowing, the highest parts of it were occasionally uncovered, and appeared under the shape of dark spots, and by the return of the fiery liquid, they were again covered, and in a manner successively assumed different phases;" "Interruptions of continuity in the bright envelopes immediately surrounding the sun," "Cavities" etc.
Overestimate of the Degree of Spot-shadow.
Public sentiment in regard to the degree of darkness which is disclosed in sun-spots is exceedingly erroneous. It is believed that the spots are really dark. Zöllner, however, states that "The black umbra of a spot emits four thousand times as much light as that derived from an equal area of the moon." "The blackest part of the spot is intrinsically bright."
What They are not, and what They are.
These phenomena may not arise from disruptions taking place on the sun's surface, neither from violent agitations near that surface. The essential and intimate character of the so-called sun-spots may be found in the interruptions of continuity in the fluid occupying the solar cone-space. This fluid which we call sunlight intercommunicates between the entire opposing surface of sun and earth, unless interrupted by some temporary cause. Any cause which is capable of producing results of such character and magnitude can only act by more or less completely interrupting the development or transmission of this fluid.
The result of such action would be disclosed to us by a decreased brilliancy in the direction of the sun. The so-called sun-spot would be in character, magnitude, form, and shade proportionate to the extent and character of the disturbing force. The permanence or evanescence of the spot would indicate the sun or earth as being the locality of such derangement. The more permanent form being developed at the sun, and the more ephemeral at the earth.
Any forces in operation at the earth which might interfere with the intercommunication of light, would lessen the brilliancy of the light, at the earth-extremity of the cone-space; and the deficiency thus produced would disclose to an observer at the earth all the appearances of a spot upon the surface of the sun. The so-called spot, thus produced, might therefore not be regarded as a veritable spot upon the sun's disc, but rather as an optical illusion.
They are Caused by Magnetic Perturbations.
What may be the forces in operation on the part of the sun, and earth alike, which may so interfere with the development or transmission of light through the solar cone-space?
The condition of the contents contained within the enclosure of the sun-crust and earth-crust, is presumably one of unrest; its actions varying from repose to the most violent agitation, with a tendency to the cyclonic in its motions. Although the earth-core may not be presumed to be an entire moving mass, yet it is known to be in a measure incandescent, and molten. Magnetic storms occur within our earth-crust which sway the needle without, and almost instantaneously manifest their presence over areas of more than half the globe. The same phenomena are undoubtedly present in increased development at the sun.
We may therefore with reason suppose that perturbations, however produced, occur within those spheres, of such an extent and character as might be a sufficient cause of the interruption of development, or of transmission of that fluid.
Inconsistency of the Present Accepted Philosophy.
The ephemeral or evanescent character of many of the so-called sun-spots, removes them from the domain of sun-phenomena, otherwise than in appearance.
Figures that are Deceptive.
Some of these spots even of large dimensions come into the field of view almost instantaneously; and as suddenly disappear. Thus Krone "observed a spot of no inconsiderable dimensions which sprang into existence in less than a minute of time." Dr. Wollaston says:—"I once saw with a two-inch reflector a spot which burst in pieces as I was looking at it." Biela also notes that "spots disappear sometimes in a single moment." Sir William Herschel "turned away his eyes from a group of spots he was observing, and when he looked again the group had vanished."
Of those who attempt to make an estimate of these phenomena by mathematical formulæ, we would ask, What velocities must these sudden and apparently widespread outbursts represent, if they take place at the sun?
Effects of these Wonderful Phenomena.
That this phenomenon is a result of an interruption of the solar current is rational to suppose. It is indisputable that the interruptions which produce these manifestations have an important bearing upon terrestrial phenomena. Winds, storms, vegetation, healthfulness, are manifestly influenced, and in a measure controlled by these perturbations.
Mistaken Conceptions.
The claim of many scientists that spot periods may be calculated, and classified, possesses no element even of probability, much less of fact, to sustain the supposition. The evanescent character of many of these spots places them beyond the sphere of statistical calculation.
May not be Tabulated.
Not even concerted and systematic investigation can insure reliable conclusions, for persons separated by even inconsiderable distances would not always observe precisely the same spot manifestations. Moreover, the spots appear and vanish so quickly that no correct estimate can be made at any single locality. As well attempt to map and chart the aurora borealis.
Unbiassed Estimate of their Character and Location.
Scheiner was one of the first who ever observed these spots through a telescope, and was therefore uncontrolled by theories in his estimate of their character and location. He held it "impossible that they could be on the sun itself," and imagined some of them to be "as far from the sun, as the moon, Venus, or Mercury."