SOLAR ACTIVITY IS HIGH: Suddenly, the sun is very active. Yesterday, Earth-orbiting satellites detected two powerful X-class solar flares. This interest-compressed movie from NASA's Solar Dynamics Observatory shows both: The northern flare ( X 1. 8 ) came from active sunspot 4274. The southern flare ( X 1. 1 ) came from a sunspot hidden behind the sun's limb. It was probably more powerful than its nominal classification because the flare was partially eclipsed by the edge of the solar disk. Ther