Farside Flare

The sun is not so quiet after all. On Aug. 31 at 2055 UT, NASA's STEREO-A spacecraft observed a strong solar flare on the far side of the sun. The flash of electromagnetic radiation briefly saturated several pixels in the spacecraft's extreme UV camera:

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Earth-orbiting satellites did not detect this flare at all. The entire body of the sun shielded us from the radiation. Only STEREO-A, hovering over the farside of the sun, was able to observe the event.

The source of the blast appears to be old sunspot 1100. Solar rotation will turn this active region back toward Earth for possible geoeffective action in about 8 days. Stay tuned.