I'm asking a question that has bothered me for years and years.
First of all, let me give some context. I'm a layman in physics
(college educated, math major). I've read Feynman's QED cover to
cover, and watched his messenger lectures. My hope is to get an
answer at the "Feynman level", ideally in the crystal clear
terms that feynman himself uses :) Okay, so with that out of the
way, my question is about transparency. My understanding from
Feynman and other materials is that when a photon hits an atom,
the photon can either be absorbed, or absorbed and released.
What I don't understand is how transparency could arise from
this. If the light were absorbed and then a new photon emitted,
it seems incredible that the new photon would have the exact
trajectory as the old one. Why wouldn't it go off randomly in a
random direction? Here's some of the homework I've done trying
to find out the answer on my own: 1) Transparency of materials
(one commentor alludes to scattering not being explained here)
2) http://alemas