Panel IV of the solar surface was distinguished by nothing special. However, Jung did not provide a true interpretation of this phenomenon. Three years passed, and the Dutch researcher P. Zeeman suggested that spectral lines undergo splitting in a magnetic field, meaning that instead of one spectral line, two appear. This discovery, predicted by Faraday, was made by Zeeman while studying the spectrum of a sodium flame placed in a strong magnetic field. Instead of one yellow sodium line, two or three appear, depending on whether the spectrum of the flame is observed along the magnetic field or perpendicular to it. H. Lorentz explained Zeeman’s phenomenon as a strong complication of the magnetic field; instead of oscillating in a straight line, the electron describes a star-like figure, which correspondingly alters the spectral line. The consequences derived by Lorentz from his theory were brilliantly confirmed by Zeeman’s experiments. In 1903, Hale proved that the cause of the splitting of spectral lines in sunspots is magnetism. It turned out that the spots are colossal magnets. When one of the poles, either the south or the north, of such a magnet is turned toward us, the other is located somewhere in the depths of the Sun. Hale called these spots unipolar. Next come bipolar spots, both poles of which we can observe, and finally, multipolar spots, consisting of a group of poles turned toward us. About 60% of all sunspots have two poles—north and south—on the surface of the Sun.
Out of 970 spots recorded from 1915 to 1917, more than half turned out to be of opposite polarity, followed by spots with uniform polarity (32–35%) and then multipolar spots (1–2%). Bipolar spots must be connected to each other—their channels descending into the depths of the Sun must meet somewhere there, forming something like a giant curved tube. Finally, there is one more type of spots. These are “invisible” sunspots. They are also of great interest, as they apparently have the ability to exert a certain influence on the Earth during the passage of the plane of solar storms through the central solar meridian.
Under “invisible” spots, as Hale explains, we should understand areas of the Sun where spots do not yet exist but will soon appear. This is the birthplace or new formation of a sunspot, which is not yet visible to the eye but can be detected by a number of accompanying phenomena on its surface, obtained in certain forms on spectrograms.
What phenomena in the substance of a sunspot cause the emergence of a magnetic field? Most likely, the main role here is played by the vortex motion of gaseous matter, the flows of electric particles—electrons. The rapid vortex motion of electrically charged particles gives rise to the appearance of convectional electric currents. A convectional electric current always arises when electricity, being at rest relative to the conductor, moves together with this conductor relative to other bodies. A convectional current is accompanied by conduction currents in adjacent conductors; these latter currents can even arise if the convectional current is constant in magnitude and direction. At the same time, we know that with a constant galvanic current, no currents arise in adjacent conductors. Despite this difference between a convectional current and a galvanic current, both of these currents generate a magnetic field around themselves, the magnitude and direction of the tension of which are determined by the same law of Biot and Savart. The magnetic effects of electric convection were first detected by Rowland in 1879. However, according to Ch. Abbot, the electrification of the spot’s vortex may arise due to the friction of particles of heterogeneous substances carried in the vortex. Abbot draws this conclusion from the assumption that in the central part of the vortex, due to the relatively low temperature (up to 350°C), the formation of liquid and even, apparently, solid particles should be expected.
Among subsequent works aimed at explaining the nature of sunspots, the theory of W. Bjerknes stands out. We must also mention another remarkable phenomenon in the distribution of spot polarity over time. Research by Hale on the distribution of magnetic forces in sunspots showed that in groups of two spots, the magnetic poles are distributed as follows: during the same 11-year cycle, which begins with the next minimum, in the same hemisphere of the Sun, one and the same pole (for example, the north) is always (in all groups) located in the spot that goes ahead, while the other is in the opposite hemisphere, where the leading spot has the other, i.e., the south, pole. Thus, the group represents something like two subsurface magnets located inside the Sun, with ends emerging outward. In single spots, the other pole, according to Hale’s findings, is not visibly manifested; such places Hale calls “invisible spots.” During the minimum period, a change in the polarity of the groups occurs. If before the minimum the leading spot had a north pole, then after the minimum in the new cycle it will have a south pole. Thus, regarding this period, solar activity should be counted not in 11 but in 22 years. This change occurs sharply, and solar activity at the time of the minimum experiences a sharp turning point. Unlike the 11-year quantitative period of sunspots, this 22-year period could be called the “magnetic period of sunspots.”
Fig. II. The influence of the planets Jupiter, Earth, Venus, and Mercury on solar activity. The upper curve is the constellation of the planets. The lower curve is solar activity (according to F. Malbure).
The periodic influence of the Sun on the Earth was usually attributed to sunspots, but it may also originate from the solar atmosphere, whose state is subject to the same periods. Therefore, studying all layers of this atmosphere is of the greatest interest. Due to lack of space, we will have to skip the discussion of other solar phenomena, such as prominences, flares, flocculi, filaments, alignments, granules, and the solar corona. We will only note that prominences, like spots, can exert a very powerful influence on terrestrial phenomena, as they are associated with enormous eruptions of solar matter, when streams of electric particles are ejected into space. Prominences have a periodicity that coincides with the periodicity of spots.
A question arises: what causes this general periodicity of solar activity? At present, a number of astronomers hold the view that, while the cause of the emergence of all solar phenomena should be sought inside the Sun, the distribution of these phenomena in time and across the surface of the luminary can be attributed to the influence of the planets. Indeed, a number of researchers (E. Fränkel, Maunder) have found periods in solar activity corresponding to the orbital periods of certain planets. It can be considered that the Sun is a sensitive instrument that responds to all changes in the gravitational field due to the movement of planets in space.
But how does this solar pulse, these periodic fluctuations in the intensity of the star’s activity, affect the Earth, and through what intermediaries are all these influences exerted? These are the questions we are now entitled to ask. However, let us first consider what energy factors the Sun produces into cosmic space, in which the Earth’s globe also revolves.
Chapter V. Earth’s Spasms Within the Embrace of the Sun
We are deeply accustomed to the idea that the Sun is extremely distant from us. One hundred forty-nine and a half million kilometers separate us from the Sun, and all terrestrial dimensions and distances seem so insignificant compared to this truly colossal distance. However, this view is fundamentally incorrect. Its fallacy stems from the fact that we do not take into account one most important factor—the dimensions of the luminary itself and the associated mass of the body and the size of the radiating surface, i.e., the gravitational force of the Sun and the power of its radiation.
If the Sun were the same size as the Earth, then the distance separating us from this tiny Sun, although it would remain the same as it is now, would at the same time be much greater! This paradox, however, becomes clear from the obvious proposition that distance in this case is a function of influence and is in inverse relation to it. Therefore, to visually represent the distance separating us from the Sun, it is necessary to measure it not in absolute units of linear measures, but in relative terms, in measures of the Sun itself. Such a measure can be the diameter of the luminary. Dividing the number of kilometers separating the Sun from the Earth by the number of kilometers in the diameter of the luminary, we obtain the number 107. Thus, the Earth is separated from the Sun by only one hundred seven solar diameters. No wonder A. Eddington, speaking of the Sun, remarks: “It is within our reach.”
Given the diameter of the Sun, equal to 1,390,891 km, as well as the enormous power of the physical and chemical processes occurring on the Sun, it must be recognized that the terrestrial globe is located in the field of its influence of enormous intensity.
Our Sun is the center of an extremely harmonious and coherent system of planets. The Sun is the “lamp of the world,” reigning at the center, in the words of the great Copernicus. When the Pythagoreans created their theory of the “harmony of the spheres,” based on elementary ideas about the motion of the planets, they could not even imagine how lawful the motions of the planets actually are and how sensitive and at the same time strong the connection of the planets is in all manifestations of their physical life.
Just as physiologists find in living organisms a connection between its individual organs, consensus partium, consisting in the regulation and coordination of various parts through the nervous and circulatory systems, so astronomers, studying phenomena in the solar system, discover in it phenomena analogous to the functions of a living organism. It took many decades of brilliant scientific development for us to merely approach an understanding of the wonderful physical and chemical processes occurring in the sphere of influence of the Sun and headed by it.
All these physical and chemical processes are largely determined by the true state of the Sun and are its derivatives. The analogy between the physiological mechanisms of a living being and the physical and chemical mechanisms of the solar system will seem even more convincing to us if we recall the connections that exist in both cases. Indeed, can we not say that the great interplanetary consensus partium is carried out by electromagnetic forces, these “nerves” through which regulatory currents flow from the Sun, and corpuscular radiations—“the bloodstream” that brings to the planets a share of sustenance for their vital activity?
No wonder Theon of Smyrna, as if foreseeing future scientific discoveries, called the Sun the “heart of the world.” Unknown to us in their nature but given to us in experience, the forces of gravity emanate from the Sun in all directions, adhering to a simple and clear law: gravity is directly proportional to the masses of the interacting bodies and inversely proportional to the square of their mutual distance. The mass of the Sun is 750 times greater than the mass of all the planets of our system combined. And mighty Neptune, moving in the peripheral orbit of the system and 30 times farther from the Sun than the Earth, is held by the Sun with the ease of a feather, taming its impulses from every point of its path to fly off along the tangent into the dark abysses of the Universe.
Of all the rich radiation of the Sun, our planet receives only one billionth of the energy it expends. However, this amount of energy is enough to fill the Earth with all kinds of manifestations of life. We will not illustrate the energy coming from the Sun with numerical data here—let us just say that they testify to
Fig. 12. Curves of average annual temperatures of cities in the USSR and the period of solar activity. The lower curve is the 11-year period of solar activity. Curves: 1 – annual temperature of Arkhangelsk (1826–1915). 2 – annual temperature of Petrograd (1826–1915). 3 – annual temperature of Moscow (1826–1915). 4 – annual temperature of Kazan (1828–1915). 5 – annual temperature of Astrakhan (1837–1915). 6 – annual temperature of Zolotoust (1837–1915). 7 – annual temperature of Kiev (1826–1915). 8 – annual temperature of Nikolaev (1826–1915). One of the annual temperature maxima occurs one year before the maximum of sunspots. In the 3rd and 4th years after the maximum of sunspots, a secondary temperature maximum falls, and the third temperature maximum coincides with the years of the sunspot minimum (according to A. P. Moiseev).
