Spaceweather.com July 19, 2012 - Sunspot complex AR1520-1521 erupted again on July 19th, this time producing an M7-class solar flare that almost crossed the threshold into X-territory. NASA's Solar Dynamics Observatory recorded the extreme ultraviolet flash: The explosion produced a bright coronal mass ejection: movie. The cloud should miss Earth. Although the explosion occured on the other side of the sun's western limb, our planet could feel some effects. The blast site is magnetically connected to Earth by backward-spiralling lines of magnetic force. Protons accelerated by the flare are being guided to us by those lines of magnetism, and a mild radiation storm is underway. Solar flare alerts: text, voice.