A Puzzle about the Sun

摘要: During the period from 19 October 2003 to 4 November 2003, there appeared three large areas of sunspot group on the sun’s surface, with each larger than Jupiter, leading to exceptionally high levels of the sun's activities. An 11-year cycle of the sunspot activities has long been recognized, and the last maximum occurred in 2000-2001 (see Fig. 1). It has been expected that next minimum will come in 2006. Does this recent short-term sunspot activity mean the interruption of the normal cycle? The answer is “no”. In terms of seasonal average or annual average, the current numbers of sunspots are still on way to drop, and the minimum around 2006 will not be missed. Actually, sunspot number almost decreased to zero for several days in the last week of January 2004. The short-lived ups and downs in the sunspot number are a normal part of the 11-year solar cycle.