Filmed over two days, the images show large glowing clouds of gas bursting from the Sun's surface and held aloft by the star's twisted magnetic fields.These huge solar prominences are several times larger than the Earth and are caused by the solar activity cycle. It is one of the most spectacular events that the twin STEREO (Solar TErrestrial RElations Observatory) craft have observed.
Seen against the brilliant solar surface in visible light, they appear as dark filaments because they are relatively cool. But they are bright themselves when viewed against the blackness of space
The Sun is a huge ball of magnetized gas and as it rotates the heat churns its subsurface layer creating enormous bubbles. The Sun's magnetic field becomes increasingly tangled and every so often large magnetic loops of gas burst out. (Daily Mail)