What Causes the Optical Illusion in the Pale Blue Dot Photo?

[Avathacis]

So as you might or might not know the Pale Blue Dot is a picture taken from the spacecraft Voyager 1 when it was 6.1 billion kilometers away from Earth.

To quote Carl Sagan: (of course there is a lot more quotable and more important material, but it serves for the question)

"Because of the reflection of sunlight off the spacecraft , the Earth seems to be sitting in a beam of light, as if there were some special significance to this small world; but it's just an accident of geometry and optics."

Can anybody explain (in detail) the "accident of geometry and optics"?

P.S. I'm not sure if this belongs in general physics (because i would guess that most of the explanation would take place on the grounds of optics and geometry) or if it belongs in astrophysics/astronomy.

 

[russ_watters]

Ant time you have a nearby bright source of light that isn't in the field of view you can still get a glare from internal reflections. It happens with eartbound pictures when the sun is nearby too.

[edit] Here's an example of the same phenomena screwing up a picture I took last week. Obviously, if the background of the pic is black, the flare looks even worse.