An area on the surface of the sun marked by a lower temperature than its surroundings and that has magnetic activity.
The number of sunspots is higher during periods of high solar activity, and varies in particular with the solar cycle.
The lighter surrounding of a sunspot with the darker central umbra.
The darker central portion of a sun spot, surrounded by the lighter penumbra.
- SOHO - Solar and Heliosphere Observatory Sunspot data and images.