for scene 48 of the video " Kepler Today - Part 1 - The Science Revolution" by Rolf Witzsche - Ice Age Ahead not Global
here for a larger image
Density wave theory
The spinners of the convoluted dream that hides the truth have gone to great length to keep the dream alive. One aspect of this dreaming is the so-called density wave theory. Since in an orbital star system every galaxy would have lost its well-defined spiral structure, the theory has been invented that the spiral appearance merely reflects a pattern of stars bunching up in wave-like patterns in certain places as they orbit the galactic center.
Index - Previous
Published by Cygni Communications Ltd.
North Vancouver, BC, Canada - (C) in public domain - producer Rolf A. F.