The current quiet solar cycle raises questions about its impact on Earth

Photo du soleil ...5 novembre 2013
Picture of the sun  …november 5 , 2013

The surface of the sun was surprisingly quiet – with fewer spots than at any time in the last century – encouraging curious scientists to wonder exactly what this might mean here on Earth.

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Sunspots were observed for thousands of years – first by Chinese astronomers and then, for the first time with a telescope by Galileo in 1610.

Sunspots appear in cycles of about 11 years – more in a daily avalanche and then decreasing drastically, before amplification again .

But this cycle – nicknamed “the cycle of 24 – has surprised scientists with its slowness .

The number of points scored because it began in December 2008 is well below the average over the last 250 years . In fact , this is less than half .

“This is the weakest solar cycle that was all from the space age , 50 years ,” said the National Oceanic and Atmospheric Association , the physicist Doug Biesecker .

Beau jeu

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The intense electromagnetic energy sunspot has a significant impact on emissions of ultraviolet rays and X rays of the sun as well as solar storms .

Solar storms can disrupt telecommunications and electronic networks Terre.L Activity sunspots can also have an impact on the climate of the Earth.

 Cycle 23 peaked in April 2000 with an average of 120 solar day points. Then the cycle wound down, hit bottom around December 2008, the time for scientists, began the beginning of the current cycle.

The minimum solar activity at the end of cycle 23 has led astronomers to predict a slow 24 cycle. But the reality is even fell below expectations .

In the first year of the cycle, during which solar activity have increased , astronomers have 266 days without a single stain sun.

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Hindu Devotees return after taking a holy dip at Sangam while the sun sets in Allahabad …
“The peak forecast was 90 sunspots,” said Biesecker, noting that even if the activity has increased over the last year, “it is very clear that he will not be close to 90.”

“The number of sunspots peaked last year to 67, almost half of a typical cycle,” he added.

The last time the sunspot cycle was this slow was in February 1906, the peak of cycle 14, with only 64 points per day.

The “long minimum: three years, three times more than the previous three rounds of the Space Age” was a surprise, said University of Montana physicist Andres Munoz-Jamillio.

A magnet switch

Une photo prise depuis un avion montre le soleil levant ...

A photo taken from an airplane shows the sun rising behind the clouds at dawn over the outskirts of Bankok
Cycle 24 also deviated from the standard of another surprising way.
In general, towards the end of each solar cycle of 11 years, the magnetic fields of the sun changes direction . The northern and southern hemispheres change their polarity , often simultaneously.

In exchange, the magnetic field strength drops to near zero and reappears when the polarity is reversed, the scientists explain .

But this time, something different seems to happen . The north pole already reversed polarity, several months ago – and now the same polarity as the south pole .

The most recent satellite measurements , ” the southern hemisphere should return to the near future ,” said Todd Hoeksema , Director of the Solar Observatory Wilcox at Stanford University .

It does not seem concerned about the phenomenon .

But scientists are watching closely to see the sun if the cycle 24 will be an aberration – or if it will calm the next solar cycle stretch through.

“We will not know for another good three or four years ,” said Biesecker .

Some researchers believe this could be the beginning of a long period of low solar activity.

The last time it happened, during the so-called ” Maunder Minimum ” between 1650 and 1715 almost no sunspots were observed. During the same period , temperatures plummeted to Earth , causing the so-called ” Little Ice Age ” in Europe and North America.

As the number of sunspots continue to remain low , it is possible the Earth’s climate is affected again .

But thanks to global warming, we are unlikely to see another ice age. “Things did not start to cool , they just do not grow as quickly ,” said Biesecker .

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