article_snippet.sent: Sunspots have a temperature of anywhere from 2,700 to 4,200°C (4,890 to 7,590°F), compared to 5,500°C (9,930°F) for the surrounding solar material, which is why they are so visible. 
article_snippet.sent: They can have a temperature of anywhere from 2,700 to 4,200°C (4,890 to 7,590°F), compared to 5,500°C (9,930°F) for the surrounding solar material, which is why They are so visible.
article_snippet.sent: the sun goes through a periodic change in activity known as a solar cycle, which has an average duration of 11 years.
article_snippet.sent: This also affects the frequency of sunspots.
highlights_snippet.sent: The number on the surface correlates with how active the sun is .
  
highlights_snippet.sent: Have temperature of up to 4,200°C (7,590°F), compared to 5,500°C (9,930°F) of the surrounding solar material .
  