NASA - Solar Cycle @LittleSDOHMI

Uploaded October 2011 | Updated September 2026, 2 weeks ago

The number of sunspots increases and decreases over time in a regular, approximately 11-year cycle, called the sunspot cycle. The exact length of the cycle can vary. It has been as short as eight years and as long as fourteen, but the number of sunspots always increases over time, and then returns to low again.

Credit: NASA

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