Images of the sun show two very distinct features near the center of the solar disk.
A large, bright and slightly heart-shaped region in the lower right is a strong sunspot group. Each sunspot in this group is actually many, many times the size of the Earth. NOAA has named this Sunspot Region 2403, and it contains an enormous amount of energy that, given a trigger, could ignite a large flare or launch a fast coronal mass ejection. These are the waves of energy that cause power anomalies and brilliant aurora here on Earth.
Active regions are characterized by strong magnetic fields and, as the loops seen in the above image suggest, have a “roof” over the top that somewhat isolates the region from the outer solar corona.
Immediately to its left on the image is a striking dark “peninsula,” marking the area of a large coronal hole. The hole actually extends from the south pole of the sun to the solar equator. Coronal holes are the “yang” to the “yin” of the active region. That is, they have weak magnetic fields, and are open to the outer corona and the interplanetary medium. Coronal holes are like solar nozzles that spout constant, high-speed solar winds.
Here’s the really interesting part; for some yet unexplained reason, strong active regions tend to emerge near the boundaries of coronal holes. For example, one of the hot active regions during the famous Halloween Storms of 2003, Region 484, was located just ahead of a large coronal hole.
Clearly there’s a lot going on in such areas — large gradients in magnetic field as well as wildly varying plasma parameters, but as with all things space weather, the part that distinguishes the most eruptive active regions from the ones that merely reside in the neighborhood of a coronal hole remains a puzzle.
At a minimum, the fast solar wind from the nozzle will disturb the earth’s magnetic field over the next few days. But having these two features — the sunspot region and the coronal hole — so close to each other, and pointed toward Earth, means we’re much more likely to see geomagnetic storms that would impact the electrical systems on which we Earthlings depend. As a bonus, they might spark some auroras to brighten the dark night.