a branch of biophysics that studies the influence of changes in solar activity on terrestrial organisms. The founder of heliobiology was the Soviet physicist A. L. Chizhevskii, whose first work in this field appeared in 1915, but other scientists, including the Swede S. Arrhenius, preceded him in relating fluctuations in solar activity to many manifestations of vital activity in the inhabitants of the earth.

Fluctuations in solar activity accompanied by periodic increases in the number of spots and chromospheric flares (11-year cycle on the average) alter the intensity of the X-ray, ultraviolet, and radio-frequency radiations of the sun and the corpuscular particle fluxes emitted by it. The cyclic variations in solar radiation affect the life processes of terrestrial organisms. For example, changes in solar activity were found to affect the growth rings of trees, the yields of grain crops, the reproduction and migration of insects, fish, and other animals, and the genesis and exacerbation of a number of diseases in man and animals.

Soviet scientists have conducted extensive research in heliobiology. A. L. Chizhevskii found a relationship between changes in solar activity and the development of epidemics and epizootics, exacerbations of nervous and mental diseases, and some other biological phenomena. The physician S. T. Vel’khover demonstrated changes in the stainability and pathogenicity of certain microorganisms during solar flares. The entomologist N. S. Shcherbinovskii observed that the periodicity of locust onslaughts corresponds to the sun’s rhythm—that is, locusts return every 11 years. The hematologist N. A. Shul’ts found that abrupt changes in solar activity affect the number of white blood cells in human blood and relative lymphocytosis.

The Italian physical chemist G. Piccardi discovered that various physical factors, particularly changes in solar activity, alter colloidal solutions. The Japanese hematologist M. Takata developed a test for the precipitation of blood proteins that was sensitive to changes in solar activity. The French physician M. Faure showed that sudden deaths and exacerbations of chronic diseases increase as a result of increased solar activity. Faure organized the world’s first solar medical service.

Research in heliobiology includes the study of the correlation between changes in a particular biological parameter (according to statistical data) and fluctuations in solar activity and testing on different biological objects the effect of conditions that simulate certain factors in solar activity. Development of the latter field has just begun. The world’s first laboratory for heliobiology was organized in the USSR in Irkutsk in 1968. Heliobiology is closely related to other branches of biology, medicine, space biology, astronomy, and physics. Its main objectives are to determine the factors in solar activity that influence living organisms and the nature and mechanisms of such influences. Forecasts of sharp fluctuations in solar activity (chromospheric flares in particular) should be taken into account not only in space biology and medicine but also in the public health system, agriculture, and other branches of science and the economy.


Chizhevskii, A. L. Epidemicheskie katastrofy i periodicheskaia deiatel’nost’ solntsa. Moscow, 1930.
Shcherbinovskii, N. S. “Tsiklicheskaia aktivnost’ Solntsa i obuslovlennye eiu ritmy massovykh razmnozhenii organizmov.” In Zemlia vo Vselennoi. Moscow, 1964.
Solnechnaia aktivnost’ i zhizn’. Riga, 1967.
Chizhevskii, A. L., and Iu. G. Shishina. V ritme solntsa. Moscow, 1969.