|Full Disc Coronal hole is in the center|
A coronal hole is an area where the magnetic lines are open. The open fields allow the material to beblown off of the surface in solar winds and then that area becomes cooler. Slightly cooler so in the ultraviolet frequency those area are less bright slightly than the surrounding area. Some people have been worried that there is something wrong with the sun that there is some enormous catastrophic hole in the sun. That is completely misunderstanding what this image is showing. First you have to remember that ultraviolet light images is recording heat not visible light like what we see. Similar to an FLIR which looks at infrared but at the other end of the visible light spectrum.
This closer and brightened image reveals there is no actual hole.
The word hole is just a industry term.
Now we can look and the magnetic lines and let me say that the lines in these images are not visible lines either they are added by physicist who use computer models and observations to map where they think that are and as you can see in the following 2 images they don't always agree with each other.
|From SDO showing the lines all OPEN.|
|Magnetic fields from GONG and edited by me to include the SDO image.|
If you are worried that a Gigantic Chuck of the sun is headed our way you should know that is not true and that region has already rotated past an earth facing position. The weather we received raised the KP index to 4