Recent content by jeremyfiennes

Thanks.

I don't know. My memory doesn't go back that far. But it us implicit in this one which I found in wikipedia: "Possible velocity vs. redshift functions; patterned after Davis & Lineweave, CC BY-SA 3.0." The 'linear' curve is the Hubble law case.

The GR predictions for the universe's size are those of fig.a. Whereas the Hubble expansion is exponential, fig.b. How are the two reconciled?

Thanks.

Electromagnetic radiation is propagating sinusoidal electric and magnetic fields. Are the peak amplitudes of these fields in any way related to the radiation's other parameters, e.g. its instensity?

There are these two options. I continue seeing problems with both. What I am after is a serious discussion of their merits and demerits, not just on a youtube video.

Ok.

Exactly. That is what I had always thought. The ref is: <https://www.feynmanlectures.caltech.edu/I_31.html>. He arrives at an equation (eq.31-19) that he says is "the 'explanation' of the index of refraction that we wished to obtain". But he doesn't give a numerical example to show that it in...

Looking throught the replies to the questions on the topic, there seem to be two main theories: absorbtion-reemission and secondary wave. The latter is described in Feynman's 1963 lecture, but which I don't find very convincing. Are there links to in-depth discussions of the two. And how they...

Do you have accessible web links discussing the pros and cons of the various theories of light propagation in dense media? I have done quire a bit of searching, but all seems rather superficial (Don Lincoln's video, f. ex.) Thanks

Agreed. But it would be nice to be able to calculate that speed from the physical data of water.

I find this all a bit mysterious. Incoming light at frequency f excites electrons, that then presumably vibrate at f and (I would have thought) re-emit energy also at f, and hence the original wavelength c/f. The fact that he simply states the slower speed without explaining it I find...

Thanks. In the video he shows them with the same wavelength. What then determines the wavelength?

I watched a Fermilab video on light propagation in water: . He says (~) at time 7:50: "The oscillating electric field of the light make electrons in the glass move. These set up a second oscillating electric field that combines with the first to make a single oscillating field. That is the wave...

Ok. Thanks.