Changing its Spots? (May 20, 2004)
Hi-res TIF image (1.9M).
Typical of the dynamic changes that occur on the Sun all the time, sunspots never stay the same size or shape for very long, though they can last for several months. In this eight-day video clip (May 11 - 19), what first appears as a cluster of small spots on the left side of the Sun, soon splits into two groups, then organizes itself into two distinct sunspots. Sunspots are the visible tracers of magnetically active regions, so here one has a north polarity and the other a south. Each of these spots is several times the size of Earth. Because they are somewhat cooler (4,000 C) than the rest of the Sun's surface (6,000 C), they appear darker.
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.
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