Table of contents: 1  Overview. 2  Detailed Reports Checklist. Statements Regarding Other IRS Filings and Tax Compliance. 3  Other organizations in North Carolina.  Affiliated organizations.
Answer: The amount of magnetic flux that rises up to the Sun's surface varies with time in a cycle called the solar cycle. This cycle lasts 11 years on average. This cycle is sometimes referred to as the sunspot cycle.
Predicting the behavior of a sunspot cycle is fairly reliable once the cycle is well underway (about 3 years after the minimum in sunspot number occurs [see Hathaway, Wilson, and Reichmann Solar Physics; 151, 177 (1994)]). Prior to that time the predictions are less reliable but nonetheless equally as important.