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)