Absence of sunspots ‘calm before a storm of energy’

Stuart Clark
New Scientist – Washington Post
Tuesday, June 22, 2010

Sunspots come and go, but recently they have mostly gone. For centuries, astronomers have recorded when these dark blemishes on the solar surface emerge, only to fade away after a few days, weeks or months. Thanks to their efforts, we know that sunspot numbers ebb and flow in cycles lasting about 11 years.

But for the past two years, the sunspots have mostly been missing. Their absence, the most prolonged in nearly 100 years, has taken even seasoned sun watchers by surprise. “This is solar behavior we haven’t seen in living memory,” says David Hathaway, a physicist at NASA’s Marshall Space Flight Center in Huntsville, Ala.

The sun is under scrutiny as never before, thanks to an armada of space telescopes. The results they beam back are portraying our nearest star, and its influence on Earth, in a new light. 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?

(Images of the sunspots from NASA)

Groups of sunspots forewarn of gigantic solar storms that can unleash a billion times more energy than an atomic bomb. Fears that these giant eruptions could create havoc on Earth and disputes over the sun’s role in climate change are adding urgency to these studies. When NASA and the European Space Agency launched the Solar and Heliospheric Observatory almost 15 years ago, “understanding the solar cycle was not one of its scientific objectives,” says Bernhard Fleck, the mission’s project scientist. “Now it is one of the key questions.”

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