Visible sunspots vary in number according to a cycle of how many years?
Solar cycle an average duration of about 11 years. Solar maximum and solar minimum refer respectively to periods of maximum and minimum sunspot counts. Cycles span from one minimum to the next. The solar cycle was discovered in 1843 by Samuel Heinrich Schwabe, who after 17 years of observations noticed a periodic variation in the average number of sunspots. Rudolf Wolf compiled and studied these and other observations, reconstructing the cycle back to 1745, eventually pushing these reconstructions to the earliest observations of sunspots by Galileo and contemporaries in the early seventeenth century. Following Wolf's numbering scheme, the 1755–1766 cycle is traditionally
Sunspots (economics) controversial but has been widespread in many areas of economics. For example, in the words of Arthur C. Pigou, 'Sunspots' have been included in economic models as a way of capturing these 'extrinsic' fluctuations, in fields like asset pricing, financial crises, business cycles, economic growth, and monetary policy. Experimental economics researchers have demonstrated how sunspots could affect economic activity. The name is a whimsical reference to 19th-century economist William Stanley Jevons, who attempted to correlate business cycle patterns with sunspot counts (on the actual sun) on the grounds that they might cause variations in weather and thus agricultural output. Subsequent