Sun heading for hibernation, say experts

(National Geographic): When our star drops out of its latest sunspot activity cycle, the sun is most likely going into hibernation, scientists announced today. Three independent studies of the sun's insides, surface, and upper atmosphere all predict that the next solar cycle will be significantly delayed—if it happens at all. Normally, the next cycle would be expected to start roughly around 2020. The combined data indicate that we may soon be headed into what's known as a grand minimum, a period of unusually low solar activity. The predicted solar "sleep" is being compared to the last grand minimum on record, which occurred between 1645 and 1715.

Known as the Maunder Minimum, the roughly 70-year period coincided with the coldest spell of the Little Ice Age, when European canals regularly froze solid and Alpine glaciers encroached on mountain villages. "We have some interesting hints that solar activity is associated with climate, but we don't understand the association," said Dean Pesnell, project scientist for NASA's Solar Dynamics Observatory (SDO). Also, even if there is a climate link, Pesnell doesn't think another grand minimum is likely to trigger a cold snap.

"With what's happening in current times—we've added considerable amounts of carbon dioxide and methane and other greenhouse gases to the atmosphere," said Pesnell, who wasn't involved in the suite of new sun studies. "I don't think you'd see the same cooling effects today if the sun went into another Maunder Minimum-type behavior."

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