Carrington-class* CME Narrowly Misses Earth   
       
   May 2, 2014: Last month (April 8-11), scientists, government officials,   
   emergency planners and others converged on Boulder, Colorado, for NOAA's Space   
   Weather Workshop-an annual gathering to discuss the perils and probabilities   
   of solar storms.   
       
   The current solar cycle is weaker than usual, so you might expect a   
   correspondingly low-key meeting.  On the contrary, the halls and meeting rooms   
   were abuzz with excitement about an intense solar storm that narrowly missed   
   Earth.   
       
   "If it had hit, we would still be picking up the pieces," says Daniel Baker of   
   the University of Colorado, who presented a talk entitled The Major Solar   
   Eruptive Event in July 2012: Defining Extreme Space Weather Scenarios.   
       
   http://www.youtube.com/watch?v=7ukQhycKOFw   
       
   A new ScienceCast video recounts the near-miss of a solar superstorm in July   
   2012.  Play it   
       
   The close shave happened almost two years ago. On July 23, 2012, a plasma   
   cloud or "CME" rocketed away from the sun as fast as 3000 km/s, more than four   
   times faster than a typical eruption. The storm tore through Earth orbit, but   
   fortunately Earth wasn't there. Instead it hit the STEREO-A spacecraft.   
   Researchers have been analyzing the data ever since, and they have concluded   
   that the storm was one of the strongest in recorded history. "It might have   
   been stronger than the Carrington Event itself," says Baker.   
       
   The Carrington Event of Sept. 1859 was a series of powerful CMEs that hit   
   Earth head-on, sparking Northern Lights as far south as Tahiti. Intense   
   geomagnetic storms caused global telegraph lines to spark, setting fire to   
   some telegraph offices and disabling the 'Victorian Internet." A similar storm   
   today could have a catastrophic effect on modern power grids and   
   telecommunication networks. According to a study by the National Academy of   
   Sciences, the total economic impact could exceed $2 trillion or 20 times   
   greater than the costs of a Hurricane Katrina. Multi-ton transformers fried by   
   such a storm could take years to repair and impact national security.   
       
   A recent paper in Nature Communications authored by UC Berkeley space   
   physicist Janet G. Luhmann and former postdoc Ying D. Liu describes what gave   
   the July 2012 storm Carrington-like potency. For one thing, the CME was   
   actually two CMEs separated by only 10 to 15 minutes. This double storm cloud   
   traveled through a region of space that had been cleared out by another CME   
   only four days earlier. As a result, the CMEs were not decelerated as much as   
   usual by their transit through the interplanetary medium.   
       
   A report by the National Academy of Sciences details the consequences of   
   extreme solar storms. MoreHad the eruption occurred just one week earlier, the   
   blast site would have been facing Earth, rather than off to the side, so it   
   was a relatively narrow escape.   
       
   When the Carrington Event enveloped Earth in the 19th century, technologies of   
   the day were hardly sensitive to electromagnetic disturbances.  Modern   
   society, on the other hand, is deeply dependent on sun-sensitive technologies   
   such as GPS, satellite communications and the internet.   
       
   "The effect of such a storm on our modern technologies would be tremendous,"   
   says Luhmann.   
       
   During informal discussions at the workshop, Nat Gopalswamy of the Goddard   
   Space Flight Center noted that "without NASA's STEREO probes, we might never   
   have known the severity of the 2012 superstorm.  This shows the value of   
   having 'space weather buoys' located all around the sun."   
       
   It also highlights the potency of the sun even during so-called "quiet times."   
   Many observers have noted that the current solar cycle is weak, perhaps the   
   weakest in 100 years. Clearly, even a weak solar cycle can produce a very   
   strong storm.   
       
   Says Baker, "We need to be prepared."   
       
   Credits:   
   Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:   
   Science@NASA   
       
   Web Links:  Severe Space Weather: Social and Economic Consequences --   
   Science@NASA  Space Weather Workshop -- home page   
       
   *Richard Christopher Carrington; see:   
   http://en.wikipedia.org/wiki/Carrington_Event#Carrington_Super_Flare   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)