Spotless days: 400 and counting

Wattsupwiththat
Thursday, Aug 14, 2008

As many of you know, the sun has been very quiet, especially in the last month. In a NASA news release article titled What’s Wrong with the Sun? (Nothing) solar physicist David Hathaway goes on record as saying:

“It does seem like it’s taking a long time,” allows Hathaway, “but I think we’re just forgetting how long a solar minimum can last.”

No argument there. But it does seem to me that the purpose of Hathaway’s July 11th article was to smooth over the missed solar forecasts he’s made. Here is a comparison of early and more recent forecasts from Hathway.

He also seems intent on making sure that when compared to a grand minima, such as the Maunder Minimum, this current spotless spell is a mere blip.

The quiet of 2008 is not the second coming of the Maunder Minimum, believes Hathaway. “We have already observed a few sunspots from the next solar cycle,” he says. (See Solar Cycle 24 Begins.) “This suggests the solar cycle is progressing normally.”

What’s next? Hathaway anticipates more spotless days1, maybe even hundreds, followed by a return to Solar Max conditions in the years around 2012.

I would hope that Hathaway’s newest prediction, that this is “not the
second coming of the Maunder Minimum” or even a Dalton Minimum for that matter, holds true.

1Another way to examine the length and depth of a solar minimum is by counting spotless days. A “spotless day” is a day with no sunspots. Spotless days never happen during Solar Max but they are the “meat and potatoes” of solar minima.

Adding up every daily blank sun for the past three years, we find that the current solar minimum has had 362 spotless days (as of June 30, 2008).Compare that value to the total spotless days of the previous ten solar minima: 309, 273, 272, 227, 446, 269, 568, 534, ~1019 and ~931. The current count of 362 spotless days is not even close to the longest.

Though, Livingston and Penn seem to think we are entering into a grand minima via their recent paper.

As mentioned in “What’s next?”, we are now adding to the total of spotless days in this minima, and since the last update in that article, June 30th, 2008 where they mention this, we have added very few days with sunspots, perhaps 3 or 4.

Adding up every daily blank sun for the past three years, we find that the current solar minimum has had 362 spotless days (as of June 30, 2008).

So it would seem, that as of August 12th, 2008, we would likely have reached a total of 400 spotless days. The next milestone for recent solar minimas is 446 spotless days, not far off. It will be interesting to see where this current minima ends up.

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