Physical Sciences: Sunspots and Planets

Abstract

MOST current literature on solar activity assumes that the planets do not affect it, and that conditions internal to the Sun are primarily responsible for the solar cycle. Bigg¹, however, has shown that the period of Mercury's orbit appears in the sunspot data, and that the influence of Mercury depends on the phases of Venus, Earth, and Jupiter. These four are the “tidal planets”; their relative tidal heights raised on the Sun are Mercury 1.15 + 0.65, Venus 2.17 ± 0.04, Earth 1.00 ± 0.05, and Jupiter 2.28 ± 0.32. The ranges of values are due to the orbit eccentricities. No other planet raises a solar tide greater than 2% of the Earth's contribution. Here I discuss the relationships between planetary tides on the Sun and number of sunspots. The effects attributed to Mercury have been neglected because of their very short period of about 3 months compared with the period of the Sunspot cycle, which averages about 11.1 yr.