The next 11-year cycle of increased sunspot activity, scheduled to begin around 2020, may be delayed for a couple of years and have a reduced magnitude — or it may not occur at all, researchers said Tuesday. Three different lines of evidence suggest that the sun, which is expected to reach its maximum sunspot and magnetic activity in the current cycle sometime in 2013, might even enter a prolonged quiet period similar to the so-called Maunder Minimum, a 70-year stretch from 1645 to 1715 in which virtually no sunspots were observed. That minimum coincided with the "Little Ice Age," in which temperatures were unusually low in Europe and elsewhere around the globe, and some researchers suggest that the two events were cause and effect — although direct evidence of that linkage is extremely limited.
"There is evidence that the sun goes into periods like that 10% to 15% of the time, and we may be due for another one," said David H. Hathaway, a solar physicist at NASA's Marshall Space Flight Center in Huntsville, Ala., who was not involved in the research. "They may be right," he added, but he said more data should be collected before reaching such conclusions. Other than potential effects on climate, a reduction in sunspots would have little direct impact on humans. Most of the terrestrial effects linked to sunspot activity — including interference with telecommunications, problems with power transmission, reduced lifetimes of satellites and other problems — occur when sunspot activity increases.
A minimum could even be a good time for space travel because there would be fewer magnetic storms that could harm humans who have escaped the Earth's protective magnetic field. Sunspots are caused by pockets of intense magnetic activity that disrupt the normal circulation of heated gases on the sun's surface, leading to areas of cooling and reduced brightness. Sunspot activity is linked to the solar cycle, in which the star's magnetic poles are reversed every 22 years. As the magnetic fields shift around during these reversals, they create sunspots through mechanisms that are not yet entirely clear.
The findings, presented at a Las Cruces, N.M., meeting of the American Astronomical Society's Solar Physics Division, represent the first wave of new data that should help physicists better understand the sun's internal workings, said William Dean Pesnell, project scientist of the Solar Dynamics Observatory operated by the NASA Goddard Space Flight Center in Maryland. "In the next five years, we should get to the point where we can run a large [computer] model that shows us where [solar] oscillations come from," said Pesnell, who was not involved in the research. Three separate studies reached the same conclusion on sunspots.
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