Monday, January 11, 2010


Thoughts on Recent Sunspot Activity

After months and months and months of very rare, tiny, short lasting sunspots, the end of the year has brought in a bevy of them, all high latitude (that is, new Cycle 24) and many of them long lasting. There have been, recently, as many as three at a time and rather than weeks or months between them, they have appeared barely a day after the last one goes away, that is, to the side of the sun away from our observation (the sun rotates and they go out of our view). The old ones (for example No. 1035) sometimes go around and come back as a so called corpse and then flare up again (current No. 1040 is old 1035 renewed). The flux density of the sun's 10.7 cm radio output, which ranges between a low of 64 (inactive sun) and high of 267 (very active sun) has finally jumped up into the 80s. So it looks like Cycle 24 is going to really get going at last.

What does that mean to us here on Earth? Well it could mean warming. Sunspots themselves are cooler (which is why they look black compared to the rest of the sun) but the ring around them is much warmer, which results in a net warming here on Earth. Also, there is a theory that increased magnetism in the sun, the source of sunspots (which are magnetic storms) causes less cosmic rays to hit our atmosphere so that we have less clouds of the type that cool the surface so that it warms a little. I'm not sure I completely embrace that theory but I do not refute it either. So all seems ready to warm up from the sun itself, right?

Well, not so fast--hold on there, kitty cat. Sunspots are not the only way to register the sun's magnetic activity.

Look at this graph.

Notice what Anthony Watt calls a "step change" in October '05 when the ap geomagnetic index dropped precipitously from a middling spike and has never recovered. Notice too that the recent index is just about zero. That is unprecedented in 165 years of observation; and perhaps we will not see any more sunspots after 2015 and sun's magnetic strength sinks below 1500 gauss. At least for a while.

So maybe 20 to 30 years of cooling is the correct prediction after all.

We'll see.


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