This has nothing to do with what photons are or aren't. In fact, the Extinction Theorem is based solely on Classical Electrodynamics, and doesn't even refer to things called "photons". Light waves (or photons) don't simply travel through dielectrics like glass as if nothing is there. The waves interact with the molecules of the glass. For discussion purposes it is simpler to refer to "photons" rather than "waves", but it makes no difference. When a photon hits the surface of a window, it is immediately absorbed by the first molecule of silica (or whatever) that it encounters. Almost as immediate, the molecule emits a photon, in a random direction. This "new" photon travels through the glass, but not very far, since it is absorbed by another molecule. This happens over and over, for all of the photons (or waves) that are incident on the glass surface. All of these random waves interact with each other (in a classical sense, this does not require quantum mechanics to discuss) in such a manner that the end result is a light wave (photon, whatever...) hitting the front surface of the window, and appearing to exit through the rear surface. How else do you explain the fact that glass has an index of refraction (implying that the speed of light is slower in glass). What slows down the waves if they simply travel through the window unimpeded? I studied this in my 3rd year undergrad course in Electrodynamics. The theory in question took a week for the professor to teach to us (and was too advanced to be included in J.D. Jackson's textbook, again, check up Born and Wolf, "Principles of Optics", if you are masochistic enough. In my 6th edition, the stuff is discussed around page 100.) On a related note, when light reflects off a metallic surface, do you think the photons are simply bouncing off the metal atoms at the surface? NO! They are absorbed by the metal's loosely bound electrons, and these electrons emit photons in response. It is these emitted photons (waves, whatever...) that we see "bouncing" back from the metal. This isn't something I picked up on the "Internet". Just because I may be a hack photographer, doesn't mean that I know nothing about physics. I must have learned something while earning my Masters. dan c. At 10:04 PM 24-10-02 +0100, Bob Talbot wrote: > >> The only way we can see through a wiindow is through the fact that >the >> photons intefere both constructively and destructively in just right >way. >> The photons striking our retina are not the ones hitting the outside >of the >> window pane! >> >Dan > >I could start a discussion on how we don't actually know what photons >are, or even if they really exist. > >But within the context of what is currently "believed" about them ... >your talking twaddle. > > >If I have more time later I'll expand with references. For now >though. > > >Don't believe everything you read on the internet ;o) > > >Bob > > >
