When light reaches a medium, it now has other particles to interact with. Let's say the light hits an atom. The atom will then absorb the photon, and an electron in the atom will jump up into an excited state (i.e. it absorbs the photon and receives its energy). After a fraction of a second, it will lose that energy and re-emit a photon. For a fraction of a second, the photon didn't exist. It's energy was converted to that of an atom or molecule. This causes the light to take longer to reach it's goal, so we perceive it as traveling slower.
Think about throwing a baseball 20 feet. At 10 feet per second, it gets there in two seconds. If someone catches it halfway, then throws it the rest of the distance at the same speed it will take slightly longer for the ball to reach its destination because it takes time for the catcher to ready himself and rethrow it. Though it took longer to reach its goal, it still traveled the same speed the entire time it was traveling. The more catchers between the ball and its destination, the longer it takes to reach its destination despite the fact that its speed is always the same while its traveling. Of course, for the analogy to completely fit, the baseball would have to no longer exist when its caught. The catchers would absorb it into their own body and convert it into their bodies own energy. Light always travels at c, but can appear to slow down for similar reasons.
Edit: oldoldman beat me to it.
Speaking of someone else, someone else wrote a similar book. I never read either of these though.
You should get a patch for reading through an entire Smolin book. Ive done it twice...
Thankfully hes more entertaining in RL.
I say distance goes to 0 as in relative distance in your (the c traveler) frame of reverance. That is v = d/t, d = vt, d = c*0 (0 time once at c), thus you have 0 distance. Not to mention once time slows down, you dont get any more time to accelerate. To you (the guy riding the photon), it is as if you instantly hit your destination.
The way I have been modeling some of these actions, is the place two particles next to each other and treat them as if a photon that was emitted by one (and absorbed by the other 10 millions light years away) was actually just transfered directly (as if they were connected). The 2 particles act the same way regardless of the time it took for that photon to transfer that energy, and the photon itself percieved it as if the particles were connected, yet there is some spatial distance and time that the rest of the universe (our universe) sees... But like I said, any true 3d model Ive made thus far breaks down pretty fast, and you really have to look at these problems one dimension at a time (for now).
As for the higgs particle, I dont think they will find anything with the LHC (hope they dont, else Ill be wrong maybe >.>), but we will see! Very exciting times none the less.
This thread makes me sad. It reminds me of back in '01 when I was doing nuclear research. I wish I had stayed in research rather than going ops for the military. Ops is so god awful boring and so f'king limited by all the politics and top-heavy bureaucracy. I almost hate nuclear power now. I don't think I'll be able to continue it after I get out, I'm just spent.
Speaking of people more interesting in real life than in paper, I recall getting a reactor safety seminar once from one of the leads on the Manhattan Project. Guy's been walking around with a piece of uranium from the original pile reactor in a lead glass cube in his pocket... and that was only the beginning of his eccentrics, lol.
This thread makes me fondly remember all my physics classes in college and hate myself for how much I have forgotten and not kept up on in the years past.
I tried to read Three Roads to Quantum Gravity, but it just never could keep my interest. I have the same problem when I try to read any his articles in scientific magazines (he wrote for SciAm and some other magazines).
1.) Read Boring Physics Books
2.) Publish Interesting Crib Notes