On April 19, AIA observed one of the largest prominence eruptions in years. The huge structure erupts, but a great deal of the plasma (hundreds of millions of tons) is unable to escape the gravitational pull of the Sun and falls back down as “plasma rain.” As the rain impacts the surface, bright flashes can be seen as the momentum is absorbed on impact. SDO is the first observatory to capture both the rain and the impacts, allowing us to learn a great deal from observations like this.
(Spoiler alert: Look for the plasma rain begin its fall at about eighteen seconds.)
And what is “plasma?” Glad you asked. According to NASA’s glossary:
A fourth state of matter (in addition to solid, liquid, and gas) that exists in space. In this state, atoms are positively charged and share space with free negatively charged electrons. Plasma can conduct electricity and interact strongly with electric and magnetic fields. The solar wind is actually hot plasma blowing from the sun.