Sunspots are regions of very strong, concentrated magnetic fields, similar to fields associated with ordinary magnets on Earth but very different in origin and structure. Scientists look for patterns in astronomical phenomena; in sunspots, they have found an intriguing natural cycle. For reasons that are not well understood, the Sun’s magnetic field waxes and wanes in an approximately 11-year cycle. In this time, sunspots will increase from their minimum to their maximum number, and decrease again to their minimum. This process, known as the “solar cycle,” is really a 22-year phenomenon since the poles of the sunspot “magnets” reverse with each cycle. 
    Sunspots appear dark because