Every 11 years, when the solar magnetic field goes into overdrive, in some areas of the sun's surface the temperature sinks to 4000oC, so that these areas look darker in color than the surrounding photosphere. Seen from the earth they appear as small dark spots on the face of the sun, but in fact a single sunspot may be many times larger than the total surface area of the earth.
而每十一年太陽磁場發飆時，會出現溫度降為四千度的區域，相較之下顏色黯淡，從地球遙望，就是人們眼中的太陽黑子，許多黑子實際上都大過地球表面積。