Issued by the Soviet Union in 1964, this 10 kopeck stamp commemorates the International Year of the Quiet Sun (1964–1965), a global scientific program dedicated to studying solar activity during a period of minimal sunspot activity. The design vividly symbolizes Earth and the Sun, with red orbital lines and radiating solar flares representing the scientific observation of solar phenomena. The deep blue globe contrasts sharply with the radiant red sun, embodying the USSR’s pride in its achievements in space and atmospheric sciences.