NASA - National Aeronautics and Space Administration

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Credit: NASA/SDO
On Feb. 13th at 1738 UT, sunspot 1158 unleashed the strongest solar flare of the year so far, an M6.6-category X-ray irradiance magnitude blast. NASA's Solar Dynamics Observatory recorded an intense flash of extreme ultraviolet radiation. The source of this activity, sunspot 1158 is growing rapidly.

› View larger Sunspot AR1158 is growing rapidly and poses a threat for Earth-directed M-flares. Credit: NASA/SDO/HMI

Preliminary coronagraph data from STEREO-B and SOHO agree that the explosion produced a fast but not particularly bright coronal mass ejection (CME). The cloud will likely hit Earth's magnetic field on or about Feb. 15th. High-latitude sky watchers should be alert for auroras.

Tony Phillips/Holly Zell
NASA's Goddard Space Flight Center