February 18, 2011

Powerful Solar Flares Due To Strike Earth

A surge of charged plasma particles from a massive solar eruption has brushed off the Earth's northern pole, producing auroras and disrupting some radio communications, according to NASA scientists.

However, the Earth appears to have dodged a widespread geomagnetic storm, with the effects confined to the northern latitudes, possibly as far south as Canada and Norway.

"There can be sporadic outages based on particular small-scale events," said Dean Persnell, project scientist at NASA's Solar Dynamics Observatory at Goddard Space Flight Center, during an interview with the AFP news agency.

The official forecast is "for generally quiet conditions today, perhaps some minor storming tomorrow, but nothing extraordinary," he said.

The solar storm began Tuesday at 0156 GMT, with a stunning solar eruption in a sunspot the size of the planet Jupiter. 

The event produced a Class X flash -- the most powerful of all solar events, and blasted a flood of charged plasma particles known as a coronal mass ejection (CME) toward Earth at about 560 miles per second, according NASA's Solar Dynamics Observatory.

A direct hit from a CME could set off a vast geomagnetic storm as incoming particles bounce off the planet's geomagnetic field, interfering with GPS navigational systems, disrupting radio communications, and, in theory, even triggering power outages.

The China Meteorological Administration said the solar flare resulted in "sudden ionospheric disturbances" in the atmosphere above China, and jammed shortwave radio communications in the southern part of the country.

The U.S. National Weather Service's Space Weather Prediction Service called it "the calm before the storm."

"Three CMEs are enroute, all a part of the Radio Blackout events on February 13, 14, and 15 (UTC). The last of the three seems to be the fastest and may catch both of the forerunners about mid to late ... February 17," the weather service said.

However, the twisting beam of solar particles from Tuesday's eruption was passing behind the Earth without making a direct hit, Persnell said.

"In this case, it appears it will curve around and not hit us," he said.

Satellite data indicates that "the CME is quieting down and so there is not a whole lot left to it.  So it's moved well behind us by now."

Nevertheless, solar activity is on the rise, and more CMEs will likely follow, he said.

"We are seeing more and more sunspots as what we call solar cycle 24 is turning on."

"At the peak we might see several of these CMEs a day coming off the sun."

"But they have only a five to ten percent chance of hitting us. We have to be in exactly the right place for that piece of spiral to come hit us. We'll see many more coming off the sun than we have hitting us here on Earth."

Meanwhile, the British Geological Survey said the solar storm would trigger dazzling Northern Lights displays beginning Thursday.

One CME reached Earth on February 14, "sparking Valentine's Day displays of the Northern Lights (aurora borealis) further south than usual," the BGS said.

The office published geomagnetic records dating back to the early 19th century, which it hopes will assist in preparing for future storms.

"Life increasingly depends on technologies that didn't exist when the magnetic recordings began," said Alan Thomson, BGS head of geomagnetism, in an interview with AFP.

"Studying the records will tell us what we have to plan and prepare for to make sure systems can resist solar storms."

A report by a panel of NASA scientists published in 2009 entitled "Severe Space Weather Events -- Understanding Societal and Economic Impacts" said a strong, sustained and solar flare outbreak could overwhelm high-voltage transformers and short-circuit energy grids.

Such an event could cost the U.S. as much as $2 trillion during the first year, and could take up to a decade to fully recover from such a storm, the report warned.


Image Caption: Active region 1158 let loose with an X2.2 flare late on February 15, the largest flare since Dec. 2006 and the biggest flare so far in Solar Cycle 24. Active Region 1158 is in the southern hemisphere, which has been lagging the north in activity but now leads in big flares! Here is a blowup of the flaring region taken by NASA's Solar Dynamics Observatory in the extreme ultraviolet wavelength of 193 Angstroms. Much of the vertical line in the image is caused by the bright flash overwhelming the SDO imager. Credit: NASA/SDO


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