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A sun with no sun spots? What that could mean for Earth and its climate.

Three studies suggest a decline in sun spots – to the point that they could largely vanish for a long period. That could lead to fewer solar storms, as well as a chance to study whether fewer sun spots leads to a cooler climate on Earth.

By Staff writer / June 14, 2011

A photo from the NASA Solar and Heliospheric Observatory (SOHO) shows a solar flare erupting from a sun spot on Aug. 19, 2004.



Sun spots appear to be teetering on the verge of vanishing from the surface of the sun – perhaps for several decades.

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That's one possibility raised by three independent studies unveiled Tuesday at a solar-physics meeting in Las Cruces, N.M.

If the trends the studies highlight hold, the researchers say, a sun humbled by changes in its own internal workings could produce fewer solar storms during a prolonged quiet period – good news for satellite operators, astronauts, and Earthbound utility companies that must keep solar storms from triggering blackouts.

A long quiescent period also could provide an unexpected, natural laboratory for investigating often-discussed but poorly explored links between sunspot activity and global climate.

The most oft-cited example of a shutdown in sun spots is the so-called Maunder Minimum, a 70-year period that began around 1645. Sun spots virtually vanished from the sun's surface. The decline coincided with a climate period known as the Little Ice Age, when temperatures fell substantially in various locations around the globe and different times during the time span.

Researchers have been looking at this correlation with an eye toward figuring out whether and to what extent seemingly small fluctuations in sunlight that come with changes in the sunspot cycle may affect Earth's climate.

"I have not seen enough evidence either way to say whether solar activity is responsible for climate effects or not," says Frank Hill, an associate director with the National Solar Observatory in Tucson, Ariz., who led one of the studies.

But "if the next solar cycle, Cycle 25, does not occur, we'll have a splendid opportunity to find out," he adds.

On the other hand, he offers, scientists may merely be watching another cycle with a delayed onset, similar to the run-up to the current sun-spot cycle, which started more than a year late.

What are sun spots?

Sun spots are relatively cool regions of hot gas on the sun's surface, prevented by intense magnetic fields from plunging back into the depths of the sun for a reheat. These spots wax and wane in a cycle that averages 11 years.

During the peak of the cycle, the sun is at its most active, generating flares, prominences, and unleashing the granddaddies of solar outbursts: coronal mass ejections (CMEs).

All of these can occur at any time during the solar cycle, but they are most frequent during its peak.

Last week, for instance, the sun unleashed an enormous mass of charged particles in a coronal mass ejection that struck Earth a glancing blow. still, it triggered auroral displays closer to the equator than usual and anxious moments for utility-grid and satellite operators.

Evidence for a potential long-term slowdown or even halt to sun spots for a period come through three sets of measurements.


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