You think it was hot here this summer? Those bright spots on the sun are almost two million degrees Fahrenheit. They're caused by plasma falling back onto the sun's surface after being hurled outward in a flare. The image was taken on June 7, 2011, by NASA's Solar Dynamics Observatory, a spacecraft that stares at the sun 24 hours a day and continually transmits data to a dedicated ground station. This summer scientists studying the flashes of ultraviolet light caused by the infalling plasma showed how such solar activity could be used to explain observations of young stars.
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