As our closest star, the Sun gives us much of the information we know about stars in general, since it’s the only one closest enough to study in detail. One intriguing feature of the Sun is sunspots, dark spots on the surface that increase and decrease in number with the Sun’s solar cycle. Sunspots seem to hold clues to solar flares and coronal mass ejections (CMEs), two energetic types of solar activity that can disrupt local “space weather”—the term given to conditions in the outermost layers of the Earth’s atmosphere such as the magnetosphere and the ionosphere, which help protect us from solar radiation and charged particles. Such disruptions can damage everything from satellites in Earth orbit to transmission lines on the surface, and even expose astronauts to dangerous radiation.