The Sun – and CMEs

At http://wattsupwiththat.com/2012/09/21/looking-into-solar-coronal-promine… … is a fascinating post, scientists are eager to understand what causes coronal mass ejections as they are seen as a threat to satellite communications. Giant columns of hot gas or plasma leap from the surface of the Sun – often into space, others falling back to the surface. Seen from a side view CMEs appear to glow almost like a filament in a light bulb (see the image). A paper in the Astrophysical Journal of Sept 20th 2012 is the third on an ongoing series exploring the mystery, concentrating on this occasion on a cavity that appeared as the Sun in August of 2007. After observing the cavity as it travelled across the face of the Sun along with the rotation of the Sun they realised it was a tunnel – but in the shape of a crescent, somewhat like a hollow croissant. However, the temperature inside the cavity does not appear to differ from the surrounding plasma although it varied, at the bottom some 10,000 degrees C and at the top over a million degrees C.