NASA’s Solar Dynamics Observatory is monitoring a large coronal hole in the sun’s northern hemisphere.
Coronal holes are places in the sun’s atmosphere where the magnetic field opens up and allows solar wind to escape. 638 more words
UPDATE: Here is a video that makes the same point in a more humorous way :
The same temperature changes are shown for the last 500 years, but these changes are in context in the second chart. 394 more words