The biggest solar blast in four years erupted late Monday, and it's sending jets of charged particles right at Earth. The spray will spark bright auroras when it hits the magnetosphere in the next 24 to 48 hours.

A cluster of sunspots called Active Region 1158 unleashed the flare at 8:50 p.m. EST, Feb. 14 [1:50 a.m. UT, Feb. 15]. It was categorized as class X2.2, meaning it's the most powerful flare since December 2006. The sunspots have continued to let loose smaller flares and may still be active now.

As Spaceweather.com notes, the sunspots didn't even exist one week ago, and now cover a swatch of sun wider than Jupiter.

NOAA forecasters estimate a 45 percent chance of geomagnetic activity on Thursday, Feb. 17, when the bulk of the radiation hits Earth's magnetic field. The December 2006 storm was powerful enough to disrupt GPS systems.

Should the new storm prove as powerful, it could be a preview of what's expected this year and in 2012, as the sun reaches an expected maximum in its natural cycle of activity.

There is, however, a silver – and green, and yellow, and glowing – lining to the flares. In higher latitudes, where the sun's ion spray is pulled by Earth's magnetic poles, collisions between solar particles and atoms suspended in our magnetosphere produce photon sparks. Together these form the aurora borealis, or northern lights, and it looks like Earth is in for quite a show.

What's more, though a full moon often outshines the auroras, this storm may be so powerful as to mix moonlight and northern lights in one spectacular swirl. So look up! And if you take pictures, send us your best shots. If we get enough, we'll create a reader gallery.

Via Spaceweather.com

Images: NASA/STEREO

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