Sunspot

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A sunspot is a temporarily darker region on the Sun's visible surface where strong magnetic fields suppress convection and reduce the local temperature. Sunspots often occur in groups and may be associated with flares and coronal mass ejections.

The number of sunspots rises and falls in an approximately 11-year solar cycle. During solar maximum, sunspots and magnetic activity are more common; during solar minimum, the Sun may remain nearly spotless for extended periods.

The complete magnetic cycle lasts about 22 years because the Sun's global magnetic polarity reverses near each sunspot maximum and returns to its original orientation after two 11-year cycles.

Changes in solar activity affect ultraviolet radiation, the solar wind, and space weather. Total solar energy reaching Earth varies only slightly over the sunspot cycle, so recent global warming cannot be explained by changes in sunspot activity.

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• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Sunspot