September 02, 2008
UH OH: Spotless:
The sun has reached a milestone not seen for nearly 100 years: an entire month has passed without a single visible sunspot being noted. . . . When the sun is active, it's not uncommon to see sunspot numbers of 100 or more in a single month. Every 11 years, activity slows, and numbers briefly drop to near-zero. Normally sunspots return very quickly, as a new cycle begins.
But this year -- which corresponds to the start of Solar Cycle 24 -- has been extraordinarily long and quiet, with the first seven months averaging a sunspot number of only 3. August followed with none at all. The astonishing rapid drop of the past year has defied predictions, and caught nearly all astronomers by surprise.
UPDATE: Fabius Maximus notes that one observatory has found one tiny sunspot (see the update to the item linked above). He also has a big roundup on the subject.