(NBC NEWS) A giant sunspot region is starting its third go-round with a bang — in the form of the most intense solar flare recorded in more than a year.
The X4.9-class flare burst forth just as active region 1990 returned to the sun's Earth-facing side, at about 7:50 p.m. ET Monday. It set off a strong radio blackout, according to the National Oceanic and Atmospheric Administration's Space Weather Prediction Center. You'd have to go back to 2012 to find a bigger flare on the X-scale.
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