Active sunspot 1153 rotated over the sun's western horizon yesterday, ending the possibility of an Earth-directed eruption. The sunspot will spend the next two weeks transiting the sun's far side -- out of sight, but not out of view. NASA's twin STEREO spacecraft are monitoring the far side, and they will never lose track of the active region. STEREO-A took this picture just hours ago:

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© NASA
Sunspot 1153 is circled. The sunspot's magnetic canopy is filled with hot plasma, which glows brightly in this extreme ultraviolet image. Surges of UV radiation seen in this 24-hour movie show that the active region is still active indeed.

You can follow AR1153 as it swings around the back of the sun. Just download NASA's 3D Sun app for the iPhone and iPad. The app allows you to spin the sun with a flick of your finger, zoom in to inspect active regions, and fly over the farside. Best of all, it's free.

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