Recent content by 337

Hi all, For a while now I have been searching for an electrically conductive material which is also UV transparent. Anyone here has come across such a material (solid or liquid) ? Thanks :)

Thanks for your response Sylas, however, this model assumes that the object maintains a constant-velocity motion (no forces act on it) and that the rate of time passage is constant. In an expending universe with a fixed amount of matter / energy, but an increasing volume, I question the...

Hi Chronos, is there any way to determine the age of a photon (from a *stationary reference point) ? IMO determining the present size of the universe depends on how we define "present", the present we see today is only from our local reference point, so the further away we look, the further...

If there were any charges per email, it would probably help reduce overall costs of hosting and help reduce spam...

A photon remains the same object (if you can call it that) with the same properties no matter what theory you dress it up in, if 2 theories create paradoxes, that means at least one of them is wrong - this is why I prefer measuring to calculating. You mentioned earlier that photons (refering...

Ya DP - you're right. Actually if the photon is absorbed and then re-emitted with the same wavelength - I think it is in contradiction with thermodynamics (perpetual motion) and can not be correct. From what I know so far - the speed of light (so not phase-speed) is an absolute (and a limit)...

I don't have that book - will have to look it up online :cry: The only books I have at home are "Introduction to Quantum Mechanics", and "Introduction to Electrodynamics" (Griffiths) but I think they have something about EM waves in matter... However - the big question is still unanswered ...

Of course - materials have something called "extinction coefficient", which determines the path-length a photon is most likely to travel before being absorbed. When a molecule absorbs a photon - it would generally "prefer" to release whatever energy it can through rotation and vibration to...

LOL correct on all counts - and here in Europe probably 10 times more so... This is only an informative discussion in an attempt to establish the best way to "work clean" (nothing to do with the big hoax of global warming though...). As for the energy balance of both options - please give...

In an attempt to shed more photons on the subject : From source : http://en.wikipedia.org/wiki/%C4%8Cerenkov_radiation" Wiki is also using unclear terms at first, saying "the propagation speed of light in water" which is confusing but explained later on. However, there is still a...

When it comes to what a person has to do - obviously email is much easier (especially for those with an unreadable hand-writing). What about the energy consumed by delivery from source to destination over an existing infra-structure ? I think the email requires nothing more than cooling of...

Yes, that was the first thing I read, but just like I mentioned in my first post, what does the molecule get out of it ? In absorption and re-emission events you always have energy losses expressed in wavelength shifts, (not even to mention the subject emission band-width) so this means that the...

Makes perfect sense (for any type of waves) but still doesn't account for the claim that the "speed of light" (as a photon) is lower in a higher-density medium.

PD - what you say is correct - but it refers to phase-speed, not group-speed of light.

Ok : now I finally had time to read the whole thing. The lattice behavior makes more sense, however - as with any photo-molecular event - I would still expect the photon (after having been "rejected" by the lattice) to have a slightly longer wavelength due to energy losses, and since the energy...