Active region emerging

The STEREO (Ahead) spacecraft was watching in extreme UV light (March 15, 2008) as a small active region emerged from beneath the Sun's surface. The close-up video clip shows this active region (AR986) as it developed into a small, brighter area over a one-day period. In visible light, this area would be seen as a small, dark sunspot. These active regions are formed by intense magnetic forces inside the Sun that break through the surface. They can last from hours to months. This active region was not a powerful one. We followed it as the Sun's rotation carried it out of view, but it unleashed no solar storms.

• emerge171_best.mov - (6.82 mb)   
• emerge171_4.mov - (1.00 mb)   
• emerge171.mpg - (2.80 mb)   
• Print version. Right click for download.