Restless Sun

A powerful solar flare sends radiation and electrically charged particles racing into space in this January 23 image from the orbiting Solar Dynamics Observatory. The flare, which is the bright area at top left, was an explosion triggered by tangled lines of the Sun's magnetic field. Some of the energy and particles reached Earth, causing power-grid operators to take special precautions against surges of energy and airlines to reroute flights that normally pass over the north pole, which receives little protection from Earth's own magnetic field. [NASA/SDO]