http://www.eleceng.adelaide.edu.au/thz/documents/davies_2001_cha.pdf Paul Davies: "As pointed out by DeWitt, the quantum vacuum is in some respects reminiscent of the aether, and in what follows it may be helpful to think of space-time as filled with a type of invisible fluid medium, representing a seething background of vacuum fluctuations. Although the mechanical properties of this medium can be strange, and the image should not be pushed too far, it is sometimes helpful to envisage this "quantum aether" as possessing a type of viscosity."
http://www.sciscoop.com/2008-10-30-41323-484.html "Shine a light through a piece of glass, a swimming pool or any other medium and it slows down ever so slightly, it's why a plunged part way into the surface of a pool appears to be bent. So, what about the space in between those distant astronomical objects and our earthly telescopes? COULDN'T IT BE THAT THE SUPPOSED VACUUM OF SPACE IS ACTING AS AN INTERSTELLAR MEDIUM TO LOWER THE SPEED OF LIGHT like some cosmic swimming pool?"
Desperate Einsteinians refuse to answer the question: