Solar flares, among the solar system's mightiest eruptions, are tremendous explosions in the sun's atmosphere that are capable of releasing as much energy as 1 billion megatons of TNT. Solar ejections are often associated with flares and sometimes occur soon after the flare explosion. Coronal mass ejections are clouds of electrified, magnetic gas, weighing billions of tons, ejected from the sun and hurled into space with speeds ranging from 12 to 1,250 miles per second. Earth-directed coronal mass ejections cause magnetic storms by interacting with the Earth's magnetic field, distorting its shape, and accelerating electrically charged particles (electrons and atomic nuclei) trapped within. Severe solar weather is often heralded by dramatic auroral displays, northern and southern lights, and magnetic storms that occasionally affect satellites, radio communications, and power systems.