A $5 million telescope launched by NASA has sent back high-resolution images of the sun's atmosphere that help solve a 30-year-old mystery. Scientists have long wondered why the star's corona is a scorching 2 million to 4 million degrees Fahrenheit, while its surface is much cooler, at 5,000 degrees. The images show small magnetic fields creating massive amounts of tension, then breaking apart into flares that get as hot as 7 million degrees. "Sometimes this small-scale process stalls, extra stress builds up, and then the relaxation happens on a much larger scale, causing a flare or coronal mass ejection," said one scientist involved with the mission.

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