PICK OF THE WEEK
Pick of The Week
Slicing through the layers (September 17, 2002)
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Each of the images from SOHO reveals different features of the Sun
and at generally different levels, like cutting through layers to the
surface. However, some of the coronal "layers" observed here are
intertwined so these labels are somewhat arbitrary. The first two
from MDI show the photosphere or surface at about 6,000 degrees C.,
in an approximation of visible light and, secondly, in a magnetogram,
which reveals magnetic activity. Black and white indicates north and
south polarity. The next four from EIT observe the corona at
different wavelengths of extreme ultraviolet light, and at
increasingly higher levels. The orange Sun (304Å) shows ionized
helium in the lower corona at 60,000 degrees C. The blue Sun (171Å)
images ionized iron at 1 million degrees C. The green Sun (195Å)
shows even more ionized iron at 1.5 million degrees C. And finally,
the yellow Sun (284Å) yet even more ionized iron in the upper corona
at 2.5 million degrees C. Certain features can be identified in all
the images, but other features are unique to each instrument. The
video clip show the transition from one to the next as you make your
way out from the surface to the edges of the corona. Other
instruments explore the internal structure of the Sun, but that
discussion will have to wait for another day. 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. |
