Large Sunspot Group (December 18, 2009)
Hi-res TIF image (2.0M)
Solar observers were treated to the emergence of the largest sunspot group of the past several years (Dec. 14-17, 2009). As seen by SOHO's MDI instrument, the group appeared early on Dec. 14th. Since then it has fired off numerous small flares. The group is about nine Earths wide from one tip to the other. Sunspots are darker, cooler areas of intense magnetic fields and are often the source of solar storms.
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 firstname.lastname@example.org.