By David L. Brown
This is a follow-up to my post of June 29 titled “Could Quiet Sun Offset Global Warming?” (see it here.) In that piece I reported on the failure of the Sun to return to its maximum sunspot cycle, remaining a blank and featureless orange disk. As I wrote, if we are entering a new extended minima as has happened in the past, most notably during the Maunder Minimum in the 16th and 17th centuries, it could have a significant effect on global warming. High sunspot activity actually increases the amount of heat put out by the Sun, and thus an extended minima could give us a respite from global warming, helping to offset the effects of greenhouse gases.
On July 9th I followed up with a brief item titled “Sun Begins to Show Its Spots,” reporting on the appearance of a rather small and unexciting outbreak of spotting. However, that seems to have been a false alarm, since the Sun quickly returned to a condition of “Code Orange.” At left is the way it appears today, plain as a billiard 5 ball (but without the number). In fact, the similarity is so exact that I thought it would be worth posting a comparison image, as at the right below
Astronomers are vexed at the Sun’s failure to return to its usual cycle of sunspots. According to the SpaceWeather.com site, which tracks the Sun on a daily basis, the number of spot free days during 2008 was the highest since 1913 — and so far 2009 has seen even fewer spots. The average number of spotless days during an average minima is 485, and in this cycle we have already observed 733 spot-free days with no end in sight.
The Maunder Minimum is associated with the event known as the Little Ice Age, so this is a subject we should be aware of. Of course, as global warming progresses we are in no danger of any new ice ages, little or not, but at least there may be a respite from the rising temperature. I will keep an eye on this phenomenon and make occasional reports.