NASA Cassini Saturn Image: What is this?, NASA JPL
"W00005078.jpg was taken on February 21, 2005 and received on Earth February 21, 2005. The camera was pointing toward SKY, and the image was taken using the CL1 and CL2 filters. This image has not been validated or calibrated. A validated/calibrated image will be archived with the NASA Planetary Data System in 2005."
Editor's note: This raw image has been online for a week. It would seem that this image shows Saturn's shadow upon something rather tenuous. NASA JPL has yet to tell us just what it is we are looking at. Perhaps someone from JPL PAO will drop us a line.