The ‘486’ sunspot system has been hammeringus with all these exciting flasres and Coronal Mass Ejections lately, and it’s made for some good news. But now, it’s disappearing around the western limb of the sun.
So the question is, will we see this sunspot system again? The sun’s rotational period ought to bring that part of the surface back into view in about 13 days. Will the disturbance stay active that long? How long do sunspots normally survive, and do we ever see the same ones come around on successive rotations?
The reason I ask is because heavy cloud cover kept me from seeing the auroras that appeared last week. I was hoping for a second chance.
The X30 to X40 class flare and mass ejection occured when the spot group was just passing beyond the limb of the sun, so most of the junk is not headed our way. Still, it may be worth looking for aurora on the 6th when whatever is coming this way is expected to hit.
We’ll almost certainly see something when that part of the sun comes into view again. Whether it’s a very weak remnant of an active region or a strong one, we don’t know.
We now have a limited capability to look at the far side of the sun using a technique called helioseisimology. It’s the same principle as observing a powerful earthquake all over the world and calculating the earth’s density variations based on arrival time of the seismic waves. Except the sun is constantly vibrating, so we can get useful data any time.