In I. Ya. Ballakh's article the idea is put forward that explosive (non stationary) processes have played an important part in the formation and development of the solar system.
S. S. Gamburg describes an interesting similarity in the structure of the solar and planetary systems which, in the author's opinion, bespeaks the fact that these systems have been formed in stages. S. B. Pikel'ner gives an up-to-date account of the nuclear reactions considered to be the source of the Sun's radiation. He also discusses in his article the evolution of the Sun. Proceeding from some examples involving basic problems in geology, geophysics, geochemistry, and astronomy, V. V. Fedynskii points to the unexpected ways in which these sciences come into contact when projects of comprehensive study are contemplated.
Part Three, the longest in the collection, deals with the structure and development of the Earth. In his comprehensive article "The Symmetry of the Earth as Related to its Gravitational Field, Tectonics, and Hydro geology", B. L. Lichkov examines the interaction between the variations in the rate of rotation of the Earth and the motions occurring in the terrestrial crust. The article underscores the unity of the three envelopes of the Earth (lithosphere, hydrosphere, and atmosphere), and it attributes the zonality of their structure to the action of centrifugal forces. Of special interest are the author's discussions on the formation of river beds and on subsurface drainage, conditioned by the processes under consideration. T. D. and S. D. Reznichenko have written a substantial article analyzing the connection between the diurnal rotation of the Earth and tectonic and climatic processes. The authors have some original ideas concerning the transport of sedimentary rocks by rivers, which they inter pret as a process counteracting the concurrent variations in the rate of rotation of the Earth. The article presents a novel view on the course of events in the Quaternary period, which will no doubt prove most interesting.
Deep seismic sounding constitutes at present the most effective method for studying the structure of the terrestrial crust and the upper mantle of the Earth. Soviet scientific achievements in this field are described by P. S. Veitsman, in an article giving a résumé of the findings of the Conference on Deep Seismic Sounding convened by the Academy of Sciences of the USSR in 1960.
V. A. Tsaregradskii writes an interesting article in which he sustains the viewpoint of investigators who claim that the variations in the rate of rotation of the Earth constitute one of the main causative factors of tectonic processes. The author considers that the rate of rotation of the Earth is regulated by the position of the solar system in the Galaxy. Since the Sun has a period of revolution about the galactic center of about 170 million years, it follows that the orogenic cycles and other geological events in the life of our planet should recur with the same periodicity. The same view point is adopted by G. F. Lungersgauzen, in his consideration of the periodic variation of the Earth's climate in the geological past. In Lungersgauzen's opinion, the long-term variations in the climate which depend on the position of the Sun in the Galaxy can be attributed to the absorption of sunlight in the dust matter concentrated in a thin layer near the galactic plane.
V. V. Piotrovskii points out the recurrent pattern that may be observed in the morphological features of the Earth's surface, in the structure of the Earth's crust, and even in all three envelopes of the planet. According to the author, the simple mathematical relationships which describe this repeating pattern reflect an objective fact and deserve further study.
G. G. Khizanashvili discusses in his article the formation of submarine troughs, resulting from the fluctuations in the level of the World Ocean and climatic conditions. The zone most favorable for the formation of submarine troughs is thus found to be confined between the latitudes of 32 and 50°, which is indeed borne out by observation.
Many advances have recently been made in paleomagnetic research. The findings of these investigations were presented at the Fourth All-Union Conference on Paleomagnetism, of which an account is given in the article by S. Yu. Brodskaya. V. B. Neiman draws up some hypothetical hypsographic curves to describe the distribution of heights and depths on Mars and Venus, proceeding from available data on these curves for the Earth and, in part, for the Moon.