Are we in danger from the upcoming solar flare?
On March 9, 2012 at 03:58 Universal Time (7:28 PM on March 9, PDT) the sunspot, AR 1429, (the same sunspot that gave us the X5 event of earlier this week) unleashed an M6 class solar flare. The resulting Coronal Mass Ejection (CME) will reach earth’s magnetic field at 06:49 UT (10:49 PM PDT) on the evening of March 11, 2012. When the charged solar particles emitted in a CME interact with Earth’s magnetic field, a geomagnetic storm results.
Despite concerns by some, the storm resulting from this week’s X5 solar flare has been weaker than expected. If this storm increases in strength, there is a possibility of Aurora Borealis activity, or northern lights, at moderately high latitudes. The bright Moon will however interfere with faint aurora activity. In the southern hemisphere, this aurora activity translates to Aurora Australis or southern lights.
How Strong is this Solar Storm?
Many articles in the popular media have mentioned that this week’s solar storm is the strongest solar storm in nearly half a decade. An X5 class solar flare, such as we experienced on March 8th, is a quite strong solar storm, but hardly unprecedented. The reason that this storm is the strongest in several years is that the Sun has an 11 year cycle in its amount of solar activity. We are currently starting a new activity cycle after an unusually long minimum in the amount of solar activity. This particular solar storm seems strong, in part, because there have been so few solar storms over the past half decade. This strongest flare in several years does not in any way foreshadow end of the world solar storms coming in 2012.
What Happens During a Solar Flare?
During a solar flare, the Sun releases a burst of energy including significant amounts of ultraviolet and X-ray energy. Solar astronomers classify solar flares according to the amount of X-ray energy they release. The minor solar flares are C class flares. M class flares are the medium level, and the most energetic solar flares are the X class flares.
Solar flares are also sub-classified with a number from 1 to 9. Hence the least energetic solar flares are C1 flares and the most energetic flares are X9 flares. According to this classification scheme, an X5 solar flare is an energetic event, but not the strongest possible event, and the M6 event of this morning is of moderate strength.
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