Unexpected Storm

A "dead" sunspot produced an explosion of energy and particles on April 11, as shown in this sequence of images from Solar Dynamics Observatory, a Sun-watching satellite. The cloud of charged particles is expected to reach Earth on April 14, perhaps creating bright displays of the northern and southern lights and causing minor disruptions to satellites and radio communications. The Sun is early in its current magnetic cycle, which was forecast to be of below-average intensity. In the last few months, however, the level of activity has far exceeded the forecasts. [NASA/SDO]