evidence: Sunspots are dark, planet-size regions of strong magnetic fields on the surface of the sun. They can spawn eruptive disturbances such as solar flares and coronal mass ejections (CMEs). [...] The frequency and intensity of sunspots visible on the surface indicate the level of solar activity during the 11-year solar cycle that is driven by the sun's magnetic field. Sunspots are our window into the sun's complicated magnetic interior, and they have fascinated solar observers for hundreds of years. [...] Then a few years later, the poles start to flip again, everything gets reconfigured, and the number of sunspots starts to to dwindle once more.