Re: OT:Tempted to get this book
 

Slowed light is virtual phenomenon. Once photon from light ray collides with atoms of medium it transfers its energy to atom and disappears, but atom goes to hugher energy state. After some time atom re-emits photon with similar wavelenght in the same (if medium has no lens ability) or different direction and then atom goes back to initial energy state. This effect will occur many times until photon leaves meduim. Since cycle of "absorbtion-reemission" is not instant, it gives effect of "slowed light".

edit: note, that it's a very primitive explanation which assumes that photon bahaves itself as a particle. But in real world it also behave itself as a wave. And things become slightly more complicated. But the principle remains the same.

Re: OT:Tempted to get this book
 

If you'd like an Online resource The Motion Mountain is pretty famous and well respected.

Re: OT:Tempted to get this book
 

Since it brings up that 'if it only moves halfway' arguement, I'm as skeptical about it as I am about the other book.

That supposed quandry has been solved numerous times. It only moves halfway if you only look at half the time. It imposes an artificial restriction on a natural phonomenon and then claims that the natural phonomenon must follow this artificial restriction and therefore this natural canot phonomenon occur. How are we to get rid of this quandary? Same way a rational person solves all arguements involving arrows and turtles.

Re: OT:Tempted to get this book
 

Good explanation. Keep up the physics lessons!

Re: OT:Tempted to get this book
 

Ok, that makes sense. Based on your explanation, the speed of light in a vacuum is the "fastest" light can travel through any known medium, since there is virtually nothing to "slow" the light wave/particle. Therefore, the speed of light in a vacuum is the "fastest" anything can travel, as far as we know (disregarding certain quantum effects if my memory serves me well). I always knew that light behaved (under certain circumstances) as a particle and/or a wave. However, what significance does this have?

Re: OT:Tempted to get this book
 

Wave properties of light are responsible for things such as diffraction, interference and other physical phenomenons.

Re: OT:Tempted to get this book
 

Sorry, I think I was too sarcastic here.

Re: OT:Tempted to get this book
 

The "Speed of light" numbers are really "The speed of light in a vaccuum" speeds. Strangely there are certian particles that can travel faster than the speed of light when this light is slowed by going through glass or air. This is one reason why Cherenkov detectors work.

Re: OT:Tempted to get this book
 

Ah right, neutrinos and neutrino detectors would be what you're referring to. Neat little things aren't they?

Re: OT:Tempted to get this book
 

Faster than speed of light in medium. But particles causing Cherenkov radiation (like hi-energy proton) move slower than speed of light in vacuum anyway. So this is pseudo-FTL movement.