Sometimes I complain about the earthly weather, but mostly I like to post about astronomy and space events. Hope you enjoy the articles.
By: Susie77 , 8:32 PM GMT on May 02, 2014
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.
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. More
Had 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
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
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