Not by Fire but by Ice
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What's Wrong with the sun?
By Stuart Clark
14 Jun 10 - (Excerpts) - "For the past two years, the sunspots have mostly been missing. Their absence, the most prolonged for nearly a hundred years, has taken even seasoned sun watchers by surprise. "This is solar behaviour we haven't seen in living memory," says David Hathaway, a physicist at NASA's Marshall Space Flight Center in Huntsville, Alabama.
"Sunspots and other clues indicate that the sun's magnetic activity is diminishing, and that the sun may even be shrinking. Together the results hint that something profound is happening inside the sun. The big question is what?
"(Sunspots) form where giant loops of magnetism, generated deep inside the sun, well up and burst through the surface, leading to a localised drop in temperature which we see as a dark patch. Any changes in sunspot numbers reflect changes inside the sun.
"The latest solar cycle was supposed to be the most active on record. The trouble was, no one told the sun.
"(During 2008) the sun was spot-free 73 per cent of the time, an extreme dip even for a solar minimum. Only the minimum of 1913 was more pronounced, with 85 per cent of that year clear.
"As 2009 arrived, solar physicists looked for some action. They didn't get it. Again, the number of sunspots has so far been well below expectations.
"The extent to which changes in the sun's activity can affect our climate is of paramount concern. It is also highly controversial. There are those who seek to prove that the solar variability is the major cause of climate change (myself included). ... Others are equally evangelical in their assertions that the sun plays only a minuscule role in climate change.
"Mike Lockwood at the University of Reading, UK ... has studied records covering data stretching back to 1650, and found that severe European winters are much more likely during periods of low solar activity (New Scientist, 17 April, p 6).
"Another example is the Maunder minimum, the period from 1645 to 1715 during which sunspots virtually disappeared and solar activity plummeted ... ushering in a period known as the Little Ice Age.
"In 2008, Judith Lean of the Naval Research Laboratory in Washington DC published a study showing that high solar activity has a disproportionate warming influence on northern Europe (Geophysical Research Letters, vol 35, p L18701).
"There is also evidence that the sun is inexorably losing its ability to produce sunspots (see "The sunspot forecast"). By 2015, they could be gone altogether, plunging us into a new Maunder minimum - and perhaps a new Little Ice Age.
"For decades, William Livingston at the National Solar Observatory in Tucson, Arizona, has been measuring the strength of the magnetic fields which puncture the sun's surface and cause the spots to develop. Last year, he and colleague Matt Penn pointed out that the average strength of sunspot magnetic fields has been sliding dramatically since 1995.
"If the trend continues, in just five years the field will have slipped below the threshold magnetic field needed for sunspots to form."
Thanks to Ty Weston, Bill Sellers, Benjamin Napier and Siroki for this link
"Just another reason why man cannot predict anything with true accuracy, says Ty. "If the sun wants to cool down and freeze us, it will."
"What if it's going into a 'minimum' period, a la Dalton, Maunder, Sporer, et al?" asks Bill.
Stuart Clark's latest book is The Sun Kings (Princeton). He blogs at stuartclark.com
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