Originally Posted By: Bill 6
How can a person possibly know the difference between the amount of blurring affecting a close up photograph and that of a long distance one unless the camera has been located there?

Well, when I look at a picture of a light in a fog I can easily tell that the picture is blurred by the fog. So when somebody looks at a Hubble picture of a distant galaxy it should be pretty easy to tell if it has been blurred by matter in between.

Bill Gill

C is not the speed of light in a vacuum.
C is the universal speed limit.