Our sun is about five times less magnetically active than other sunlike stars—effectively a special case. The reason for this could reside in the planets in our solar system, say researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). In the last 10 years, they have developed a model that derives virtually all the sun's known activity cycles from the cyclical influence of the planets' tidal forces. In a new study published in Solar Physics, they have now demonstrated that this external synchronization automatically curbs solar activity.