Solar Prominence

Caption NASA, da "NASA - Picture of the Day" del giorno 15 Marzo 2009:"What's happened to our Sun? It was sporting a spectacular -- but not very unusual -- Solar Prominence.
A Solar Prominence is a cloud of solar gas held above the Sun's Surface by the Sun's Magnetic Field. In 2004, NASA's Sun-orbiting SOHO Spacecraft imaged an impressively large prominence hovering over the surface, pictured above.
The Earth would easily fit under the hovering curtain of hot gas.

A quiescent Prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. Although somehow related to the Sun's changing Magnetic Field, the energy mechanism that creates and sustains a Solar Prominence is still a topic of research".