This week (Oct. 18-25) SOHO watched as Active Region 917 developed into a good-sized sunspot. But, by comparing the magnetic images of the Sun to images in extreme ultraviolet light, one can see the magnetic forces that drive the features we see above the Sun's surface. In the magnetic images and video clip, the areas that are black and white indicate stronger magnetic activity. They usually appear in pairs, which makes sense if you think of them as being and acting like a magnet with north and south polarity. The magnetic forces emerge from under the Sun's surface. In the EIT 284 (yellow) observations, the brightness of the active region grows rapidly as the magnetic intensity increases. This wavelength of light is actually capturing ionized iron heated to over 2.5 million degrees in the upper levels of the Sun's atmosphere. The correlation of solar features in the two observations is very strong.

Of note: the STEREO mission launched successfully from Cape Kennedy on Oct. 25 and is on its way to studying the Sun and solar storms in 3D for the first time ever. The pair of nearly identical spacecraft should be able to send back images in a few months.

Previous Picks of the Week

SOHO began its Weekly Pick some time after sending a weekly image or video clip to the American Museum of Natural History (Rose Center) in New York City. There, the SOHO Weekly Pick is displayed with some annotations on a large plasma display.

If your institution would also like to receive the same Weekly Pick from us for display (usually in Photoshop or QuickTime format), please send your inquiry to steele.hill@gsfc.nasa.gov.