Dark Coronal Hole (October 19, 2006)
Hi-res TIF image(1.9M)
The Earth is passed through a stream of solar wind that is flowing out of this medium-sized coronal hole (on October 17, 2006). Coronal holes appear as dark area of the corona when viewed in ultraviolet light (here) and in X-rays. Since coronal holes are 'open' magnetically, strong solar wind gusts can escape from them and carry solar particles out to our magnetosphere and beyond. Solar wind streams take several days to travel from the Sun to Earth, and the coronal holes in which they originate are more likely to affect Earth after they have rotated more than halfway around the visible hemisphere of the Sun.
The magnetic field lines in a coronal hole open out into the solar wind rather than connecting to a nearby part of the Sun's surface. Coronal holes are responsible for the high-speed solar wind streams that sweep through the plane where the planets orbit -- and thus have a direct affect on "space weather" near the Earth. People living at the higher latitudes may be seeing mild geo-effective storming for the next few days in the form of auroral displays.
This same hole could reappear when the Sun rotates this area around again in about two weeks.
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.