NASA’s STEREO-B spacecraft is monitoring an active region hidden behind the sun’s eastern limb. On May 5th, it produced an impressive coronal mass ejection (CME, movie) and a burst of Type II radio emissions caused by a shock wave plowing through the sun’s outer atmosphere.
Activity has continued apace today, May 6th, with at least two more eruptions (stay tuned for movies). Furthermore, the most recent UV images from STEREO-B reveal not just one but two active regions: image.
At the root of all this activity is probably a complex of sunspots. The region is not yet visible from Earth, but the sun is turning it toward us for a better view. Readers with solar telescopes should keep an eye on sun’s northeastern limb for an emergence on May 7th or 8th.