With no sunspots actively flaring, the face of the sun is quiet. The edge of the sun, however, is not. Astronomers are monitoring three large prominences--plumes of magnetized plasma jutting tens of thousands of kilometers into space. NASA's Solar Dynamics Observatory captured all three in a single image on Nov. 27th:
None of these structures is stable. Magnetic fields holding the plasma aloft are twisted, tangled, and prone to explosive magnetic reconnection. Any of the three could erupt at any moment.
Because the prominences are so large--each one is taller than Earth--they make easy targets for backyard solar telescopes. Amateur astronomers are encouraged to train their optics on the edge of the sun.