![](c09_fig15.jpg)
Figure 9-15 RIVUXG The Sunspot Cycle (a) The number of sunspots on the Sun varies with a period of about 11 years. (b) This photograph, taken near sunspot maximum in 2001, shows a number of sunspots and large sunspot groups. The sunspot group visible near the far right side of the Sun’s disk has about the same diameter as the planet Jupiter. (c) Near sunspot minimum, as in this 2006 photograph, essentially no sunspots are visible.