Wednesday, January 25, 2012

Short Sharp Science - Solar storm engulfs Earth

David Shiga, reporter
(Image: NASA's Solar Dynamics Observatory)

A major space radiation storm has engulfed Earth. The sun unleashed a powerful solar flare yesterday, sending out a cloud of electrically charged particles, or plasma, that reached Earth today. But don't fear: the Earth's electrical systems will probably emerge unscathed.
Because of the storm, space radiation in Earth's vicinity is now at its highest level since October 2003, according to the Space Weather Prediction Center in Boulder, Colorado. The level of radiation has reached 3 on a scale where 5 is the highest. This much radiation occurs about 10 times in every 11-year solar cycle and could cause some satellites to malfunction.
When strong solar outbursts occur, the bigger concern down on the ground is the potential for disruption to power grids. Knocking these out requires a powerful geomagnetic storm, which is a disturbance in Earth's magnetosphere, a region of electrically charged particles trapped around Earth by our planet's magnetic field.
The arrival of a big plasma cloud at Earth does not always violently shake up our magnetosphere. It depends on a variety of factors including the alignment of the cloud's magnetic field relative to Earth's. In this case, forecasters are predicting only a moderate geomagnetic storm reaching 2 or 3 on a scale where 5 is the most severe. A level 3 geomagnetic storm is a common event, happening 200 times per 11-year solar cycle.
So it looks like we will be spared from the worst effects this time around. But with the sun's activity ramping up towards an expected maximum in 2013, more powerful storms are likely in store.

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