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Biggest Solar Eruption?A solar flare on June 7 unleashed a massive eruption on the sun (pictured)—perhaps the biggest ever recorded, scientists say. (Watch a video of the solar flare.)The solar flare itself—an unusually bright spot on the sun—was only a "moderate" event. Space observatories in the past year recorded about 70 such solar flares, each roughly ten times weaker than "extreme" flares, of which only two have occurred since 2007.(Related: "Biggest Solar Flare in Years—Auroras to Be Widespread Tonight?")Instead, what shocked scientists was the unusual amount of material that lofted up, expanded, and fell back down over roughly half the surface area of the sun. The event's simultaneous launch of particles into space is called a coronal mass ejection.

Image courtesy SDO/NASA