Aurora records reveal shortened solar cycle during Maunder minimum

Sunspots change in number depending on how much magnetic activity the solar dynamo generates. But there’s not total chaos: These changes occur in a cycle, which lasts about 11 years on average. The sun also experiences extended periods of low activity that can last for decades, called grand minima. The Maunder minimum, which occurred between 1645 and 1715, is often viewed as an archetypal example of the sun’s behavior during these abnormal periods.