太陽活動周期
Solar cycle 14 was the fourteenth solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 11.5 years, beginning in January 1902 and ending in July 1913. The maximum smoothed sunspot number (SIDC formula) observed during the solar cycle was 107.1, in February 1906 (the lowest since the Dalton Minimum), and the starting minimum was 4.5. During the minimum transit from solar cycle 14 to 15, there were a total of 1023 days with no sunspots (the second highest recorded of any cycle to date).