The uncertainty of science: The solar scientists at the Marshall Spaceflight Center today revised upward their prediction for the upcoming peak of the solar maximum, from a sunspot number of 60 to 76, while simultaneously delaying the arrival of their predicted peak from the spring to the fall of 2013.

Since Marshall does not archive its predictions, I am required to keep track of the revisions they make and note them here. Previously I had outlined the changes in this prediction since January 2011. Here is an updated listing:

• In January 2011, they predicted a maximum sunspot number of 59 occurring in July 2013.
• In September 2011, they raised their prediction to 70, moving it forward to May 2013.
• In October 2011, they upped it again, to 77, moving forward to April 2013.
• In November 2011, they upped it again, to 89, moving it back to May 2013.
• In December 2011, they upped it again, to 99, moving it forward to February 2013.
• In January 2012, they revised it down slightly, to 96, still for February 2013.
• In early February 2012, they kept the number at 96, but moved the maximum back to late 2013.
• In mid February 2012 they revised the number down to 63, with the peak set for early 2013.
• In March they revised the number down to 60, predicting the peak to arrive in the spring of 2013

That is where their prediction has rested, until today.

Why they should suddenly raise the prediction number to 76, but delay the peak until the fall of 2013, leaves me baffled. As they note, “Predicting the behavior of a sunspot cycle is fairly reliable once the cycle is well underway.” You would think that by now they would have faith in their prediction. Moreover, considering the lack of sunspots the Sun continues to produce, it is even more puzzling that they should raise their prediction now.