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The Sun’s Weather Impacts Earth
In March of 1989, a huge storm wracked the Sun’s surface. A few hours later, the plasma and electrons thrown out from that storm reached Earth. The HydroQuebec Power Grid in Quebec, Canada, being near the Earth’s north magnetic pole, received a huge blast from this solar storm. The geomagnetically induced currents generated in the grid by the storm’s plasma and electrons that reached Earth literally burned it out.
The power grid went down. It was down for nine hours.
But HydroQuebec was not the only power company to feel the effects of this solar storm. New Jersey Public Service Electric and Gas had two of its main transformers blown out.
All this damage was caused by a Coronal Mass Ejection(CME) of plasma, electrons and radiation from the Sun’s Corona.
Our electric power grids are particularly susceptible to such damage from CMEs because the CMEs can induce extremely high currents in them and burn them out.
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What is the Corona?
The Sun’s corona is a strange layer of the Sun. We can see it only during eclipses, or with special instruments such as spectroheliographs. It surrounds the solar sphere probably for a million miles out into space. It is pure plasma—very hot ionized gas. In fact, the Corona is hotter than it should be in theory.
The temperature of the visible ‘surface' of the Sun—the photosphere--is about 5000 degrees F. The temperature of the Corona is as much as two million degrees F.
This seems to defy the laws of physics. As you move away from the Sun the temperature should drop. Something has to be heating the Corona.
It was not until the deployment of the SOlar and Heliospheric Observatory (SOHO), and the more recent Transition Region and Coronal Explorer (TRACE) that we got a clue as what this mechanism might be.
It seems the surface of the Sun is covered with small, short term magnetic fields that appear and disappear over an average period of 40 hours. As these fields move across the Sun, they come in contact with each other. Because fields can’t intersect, they are rearranged and reconnected, and this heats the Corona.
Researchers do not have absolute proof yet this is the answer, but it is a big step in understanding the Corona.
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What is a Coronal Mass Ejection?
A Coronal Mass Ejection (CME) is a sudden and massive expulsion of plasma from the Corona. It is caused when magnetic storms sweep through the chromosphere and photosphere. These storms transmit their magnetic energy into the Corona and literally blow huge masses of it into space. If the Earth is in the right place, the CME will wash over this planet like a tsunami.
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The Damage is Widespread
It isn’t just power grids that fall prey to these blasts from space. On June 4, 1989, in the midst of a huge solar storm, a gas pipeline in Russia exploded, destroying part of the Trans Siberian Railroad and killing 500 people.
The geomagnetic, solar storm caused by the CME had set up currents in the pipeline that ignited the gas.
And then there are our satellites. They are particularly prone to damage by CMEs, because the high energy electrons can knock out circuits, and scramble guidance and control systems. A number of satellites have been disabled over the years by CMEs. Weather and communication satellites have been disabled often.
The astronauts on the ISS are not immune to danger either. Besides plasma and electrons, CMEs send dangerous radiation our way. The ISS has shielded compartments they can retreat to for safety—if they have sufficient warning.
Airlines divert flights from the poles during CMEs because the geomagnetic disruption, and the possible disruption of navigation satellites, which can affect navigation. The radiation could also be a danger to passengers and crew.
CMEs are not the only danger our Sun sends our way. There are also solar flares. We’ll see what danger lurks there in Part 2.
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Sources and Credits
University of California at Berkeley: http://ds9.ssl.berkeley.edu/LWS_GEMS/pdfs/cannibal.pdf
University of California at Berkeley: //ds9.ssl.berkeley.edu/LWS_GEMS/pdfs/cannibal.pdf
National Oceanic and Atmospheric Admistration: http://www.magazine.noaa.gov/stories/mag131.htm