Sunspot

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A sunspot is a temporarily darker region on the Sun's visible surface where concentrated magnetic fields suppress convection and reduce the local temperature. Sunspots often appear in groups with complex magnetic structure.

Sunspot numbers rise and fall in an approximately 11-year cycle. Solar maximum has many spots, flares, and coronal mass ejections, while solar minimum may include long intervals with few visible spots.

The Sun's global magnetic polarity reverses around each maximum, giving the complete magnetic or Hale cycle a period of about 22 years. Individual sunspot groups usually persist for days or weeks.

Sunspot observations provide one of the longest records of solar activity. Solar cycles affect ultraviolet radiation, the solar wind, cosmic-ray modulation, auroras, satellites, radio communication, and other aspects of space weather.

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