Behemoth sunspot 1302 unleashed another strong flare on Saturday morning--an X1.9-category blast at 5:40 am EDT. NASA's Solar Dynamics Observatory (SDO) recorded the extreme ultraviolet flash.
A NASA SDO movie shows a shadowy shock wave racing away from the blast site. This is a sign that the blast produced a coronal mass ejection (CME) that could deliver a glancing blow to Earth's magnetic field on Sept. 26.