The NASA Solar Dynamics Observatory has released a beautiful video of a large coronal hole, which was a large feature on the Sun the week of November 30, 2014.
Coronal hole are areas where the Sun’s magnetic field is open ended and where high–speed solar wind streams particles into space. The area appears darker there because there is less material being imaged in this wavelength of extreme ultraviolet light. At its widest point, the hole extends more than 50 times the size of Earth.