The sun emitted a significant solar flare, peaking at 7:28 p.m. EST on Dec. 19, 2014. NASA’s*Solar Dynamics Observatory, which watches the sun constantly, captured an image of the*event. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass*through Earth's atmosphere to physically affect humans on the ground, however -- when*intense enough -- they can disturb the atmosphere in the layer where GPS and*communications signals travel. This flare is classified as an X1.8-class flare. X-class denotes the most intense flares, while*the number provides more information about its strength. An X2 is twice as intense as an X1,*an X3 is three times as intense, etc. Image Credit: NASA/SDO

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