January 15, 2015.
Sun starts the year with huge “hole” near its southern pole
The sun shone first in 2015 with a huge coronal hole – a darker region of low density – near the star’s southern pole. The phenomenon was captured on January 1st by a Solar Dynamics Observatory instrument of NASA’s , the US space agency.
According to NASA, the coronal holes are regions of the outermost layers of the sun, called coronas, where the magnetic field extends into space rather than be contained on the surface of the star. The particles moving along these magnetic fields can then leave the sun instead of getting stuck on its surface.
If you want to know how magnetic fields work, take a look on the video: https://www.youtube.com/watch?v=hFAOXdXZ5TM
While the particles remain trapped on the surface, they shine. The regions in which the particles escaped into space are much darker, with the appearance of a hole.
If you want to know more about this event, access: http://science-world.olanola.com/blog/43428294053/The-Mystery-of-the-South-Pole-in-the-sun