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Three days ago, on August 1st, 2010, a great mass of plasma was ejected from the sun.  The cloud of protons and electrons reached earth last night where it collided with the planet’s magnetic field to produce a series of spectacular aurora lights.  Because of the strength of the coronal flare, the dancing streamers of red and green fire were visible across much of the temperate part of earth and not just near the poles.  A second coronal mass ejection is due to arrive tonight.  These are the first big coronal flares which have headed towards earth for quite a while so, unless you are a jaded Inuit or world-weary arctic explorer, you should keep an eye towards the nearest pole.

An animation of Aurora Australis sweeping over the South Pole.

The sun is entering an active portion of its eleven/twelve year sunspot activity.  The peak year is projected to be in 2013.  Solar activity was mild throughout the twentieth century, but our star has not always been so quiescent.  At 11:18 AM on September 1st, 1859, a British astronomer, Richard Carrington, was observing a projection of the sun on a yellow glass and illustrating the sunspots he saw.  Suddenly, in the midst of a great boiling mass of spots, two kidney shaped points of light formed and grew intensely bright.  Here, halfway down the page,  is Carrington’s hilariously Victorian description of the event taken from NASA’s website.

Carrington was the first to directly witness a coronal mass ejection, when the sun’s opposing magnetic fields rip great hunks of plasma into space. After traveling 93 million miles, the particles from the 1859 ejection created spectacular aurora lights visible as far south as the Caribbean.  Blood colored light shone across the night skies of the world. The solar storm played havoc with telegraph wires and the telecommunication system of the day was rendered completely unusable.  Parts of the system burst into flame.  Keep in mind this was 1859 so telecommunications consisted of ponies, men with semaphores, and a handful of telegraph wires.  If a storm of such magnitude struck today, it would fry our communication satellites like chicken livers and do horrible, horrible unspeakable things to our electric and fiber optics grids. From beryllium deposits in polar ice cores we know that solar storms of the magnitude of 1859 are rare.  They usually occur once every five centuries or so.  However the sun is famously unpredictable.

A 2002 Solar Flare

These days we do not have an Englishman sitting in a study looking at a bright circle on a straw-colored sheet (or maybe we do, but he is unimportant and rather silly). Humankind now has a fleet of spacecraft which continuously monitor the sun (perhaps you might take a moment to reflect on how remarkable that sentence is).  Here is movie taken by the Transition Region and Coronal Explorer (TRACE) of a coronal mass ejection which occurred in 2001.  The sun is behind the opaque dot in the middle. Notice how the exotic radiation from the flare’s peak addles the craft’s movie making ability.

TRACE is a mission of the Stanford-Lockheed Institute for Space Research, and part of the NASA Small Explorer program

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