The key thing to note about Coronal Holes is that they are one of the causes of solar winds which, in turn, cause the Northern Lights to appear in our skies. Although less violent than Coronal Mass Ejections (the other source of solar wind), they are more stable. So much so, that they often reappear 27 days after their first appearance on the surface of the sun.
If you read our blogs regularly then you will remember that we recently discussed why we really love Coronal Holes (if not you can catch up here). Not only do Coronal Holes produce high-speed streams of Solar Wind which often manifest themselves as the Northern Lights but they also help in predicting Auroral activity too.
Quite some time ago, we wrote an article debunking fears that the Northern Lights are set to disappear as the Sun approaches a period of reduced activity known as Solar Minimum. The article highlighted that yes, solar activity is likely to reduce but, happily, the incidences of Coronal Holes is expected to increase.
The Sun is currently in the declining stage of Solar Cycle 24 and this has prompted some speculation that Auroral displays will become less commonplace. Fortunately, this is not the case because the Aurora stems from two sources: Coronal Mass Ejections and Coronal Holes.
During the declining stage of the Solar Cycle it is the less violent but more stable Coronal Holes that are the more likely to cause the Northern Lights to dance in our night skies and the beauty of these holes on the SUN’s surface is that they can come round time and again.