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Skies see burst of solar eruption occurring on St. Patrick’s Day

If you happened to be in one of the northern U.S. states over the weekend you would have been in for quite a show in the sky on St. Patrick’s Day. Why? According to spaceweather.com a CME impact during the early hours of March 17th sparked auroras in the United States at least as far south as Colorado. This impact caused the skies over North America to turn green on St. Patrick’s Day.
To better understand this phenomenon we will look a little deeper into what exactly a CME is, what causes it, and why should we care about it. CME stands for coronal mass ejection and is a massive burst of solar wind and magnetic fields rising above the solar corona or being released into space.
Basically they are large clouds of plasma and magnetic fields that erupt from the Sun. They can erupt in any direction, but only when the cloud is aimed at Earth will it potentially have any effect. As the CME moves through the plasma-like material that fills the solar system, it can create a disturbance known as a geomagnetic storm.
These geomagnetic storms are what have an impact here on Earth. Most commonly, the storms result in auroras, the “Aurora Borealis” in the Northern hemisphere and the “Aurora Australis” in the Southern hemisphere. However, geomagnetic storms can also disrupt communications or navigation systems.
The most damaging effect that can be produced is damage to the electrical power grid. The geomagnetic storm can induce electrical currents in the long power transmission lines, which can damage transformers. In extreme conditions, this can lead to a cascading power failure.
The most severe geomagnetic storm on record happened on September 1, 1859. The storm caused telegraph systems all over the Northern hemisphere to fail and even shocked some telegraph operators.
Studying the surface of the sun can reveal small, dark areas that vary in number and location. These sunspots result from the interaction of the sun’s surface plasma with its magnetic field. It takes approximately 11 years for the sun to move through the solar cycle that is defined by an increasing and then decreasing number of sunspots. As it reaches the close of a cycle, new sunspots appear near the equator, while a new cycle produces sunspots in higher latitudes.
As of early 2011, solar cycle 24 was under way, headed toward a peak of activity expected in 2013. The magnetic field lines that twist up to form solar flares occasionally become so warped that, like rubber bands under tension, they snap and break, then reconnect at other points.
The gaps that form no longer hold the sun’s plasma on its surface. Freed, the plasma explodes into space as a coronal mass ejection (CME). It takes several hours for the CME to detach itself from the sun, but once it does, it races away at speeds of up to 1,000 km (more than 7 million miles per hour).
The cloud of hot plasma and charged particles may be up to a hundred billion kilograms (220 billion pounds) in size. As with solar flares, if the CME is aimed in our direction, it takes the particles eight minutes to reach Earth. However, the particles take anywhere from one to five days to travel the distance to our planet.
The solar wind, a constant stream of charged particles ejected by the sun, acts on the cloud like a current on a boat. Faster CMEs feel the drag of the wind and slow down, while those with low initial velocities speed up.
NASA is currently implementing Project Solar Shield to provide warnings to vital systems after an Earth-affecting CME occurs. This allows satellites and power transformers to be shut down if necessary for a short period of time. The result is a short- term, controlled blackout rather than a longer one caused by the destruction of vital equipment.