Flare for destruction

030117 solarstorm 1

Here we see the disturbing effect of one of the most powerful solar storms ever recorded.

Over two weeks in October and November 2003 the sun was unprecedentedly active, with giant sunspots – more than 10 times the diameter of Earth – generating flares on an almost daily basis.

Solar flares are classed according to the energy they release at X-ray wavelengths. There are five major categories: A, B, C, M and X, further divided into 10 subclasses. M1 flares are 10 times more powerful than C1, and X1 flares are 10 times more powerful than M1 flares, or 100 times more powerful than C1.

Some of the flares witnessed in this two-week period were so powerful they broke right through the top of the X-class range, which is usually given as X10. A flare erupting on 4 November was estimated to have reached at least X28.

The image was taken by SOHO’s LASCO C3 instrument. A special disc (indicated by the large blue circle) inside the instrument blocks the sun (indicated by the inner white circle), so that details of the extended outer solar atmosphere can be observed.

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