SPACE ANGELS

there's a part 3/4 of the way through this odd video where, you see....

"Just as sound bounces off walls of a canyon, so too can light waves create an echo by bouncing off dust clouds in space. The light from these echoes travels a longer path than the light that travels straight toward us, and so can be seen hundreds of years after the supernova itself."

http://chandra.harvard.edu/photo/2008/snr0509/E509_lg_web.mpg