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DanMP

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About DanMP

  • Rank
    Atom
  • Birthday 03/15/1968

Profile Information

  • Location
    Cluj-Napoca, RO
  • Interests
    physics, cycling, mountains
  • College Major/Degree
    Babes-Bolyai Univ. - Physicist
  • Favorite Area of Science
    physics
  • Occupation
    Physicist (IR & Raman spectroscopy)

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  1. I'm sorry to disappoint you but what I posted was a theory (not experiment) about waves of light through a medium, not single photons passing through slits, so I don't think it can support your "theory". Indeed. The reason I posted it was the fact/idea that many physicists are not really interested in "how is energy conserved" ... But they should be. You can't create photons/energy without consuming/absorbing an equal amount ... According to wikipedia so, if "The charges thus radiate their own electromagnetic wave that is at the same frequency" and "The light wave traveling in the medium is the macroscopic superposition (sum) of all such contributions in the material: the original wave plus the waves radiated by all the moving charges", the resulted wave (the sum) appears to "contain" more photons than the original/incident wave but, as I wrote above, you can't create photons/energy without consuming/absorbing an equal amount, so something is wrong ... What is wrong? [This is a bit off-topic (sorry!), so maybe we should move it (and continue) in another location.]
  2. This is a good point, in my opinion, but the microscopic explanation of how light is slowed in transparent materials suggests that new photons do occur (when we have a wave of light, not one photon at a time): and nobody seem to be bothered abut "how is energy conserved?" ... (Many physicists were more bothered by the fact that I asked the question: see 1, 2, 3).
  3. Ok what you did wrong was not the actual swapping, but the fact that you didn't notice that the notations were different. In your LT calculation (not derivation, sorry) S' was moving to the right, while in the geometrical calculation, S was moving to the right, as you can understand from the picture and its caption: As I wrote above, in order to compare the results, you have to keep the same scenario/notations, because (unfortunately) the notations are not the same everywhere, as you may see also in other 2 examples/derivations: https://www.amnh.org/learn/pd/physical_science/week3/time_dilation.html https://phys.libretexts.org/Bookshelves/University_Physics/Book%3A_University_Physics_(OpenStax)/Map%3A_University_Physics_III_-_Optics_and_Modern_Physics_(OpenStax)/5%3A__Relativity/5.3%3A_Time_Dilation
  4. The formula is the same. The problem is that you swapped the frames. Time dilation is usually calculated for a clock (it doesn't matter if it is a light clock as in your link or any other clock) and from a reference frame. In your LT derivation the clock was static in the origin of S' (the condition was x'=0), while in the geometric calculation the clock was static in S frame (the initial x' was different than the final x', while x was 0 all the time). So, in order to compare the results, you have to keep the same scenario/notations and to swap t' with t in one of the calculations.
  5. The above shows (correctly) that for "SC1: x' = 0, x = vt", when the primed clock (consider it a light clock) is in the origin of the S' frame (x'=0), moving with the speed v away from the origin of the S frame (x=vt), Lorentz transformations yield: t'= t/γ (where t' and t are in fact Δt' and Δt, time intervals from the moment t1'=t1=0 when x1'=x1=0). On the other hand taken from: (more precisely https://en.wikipedia.org/wiki/Time_dilation#Velocity_time_dilation) is valid for x=0, not for x'=0 as in "SC1" (where x' and x are in fact Δx' and Δx), so t and t' are swapped ... This is the origin of the "error". In fact Lorentz transformations are correct, as we all know.
  6. Ok, thank you! I apologize for insisting with this question.
  7. I'm sorry but it was you who insisted to talk about that particular derivation : I referred to your source, so I'm not really off-topic. Sorry anyway, I just wanted to understand it better. When I wrote "you", I meant:
  8. The origin of the confusion(?) is not really Jan Slowak, as you can see in the pdf offered here. This is odd, because it is the second time I posted this question in this thread. First time was yesterday. So, again, why v'=v (in value, because in fact v'=-v)?
  9. It is also unbelievable that you don't have an answer to my question. I'm still waiting ...
  10. Yes, but when in S' we write x' and t' ... Why not also v'? The speeds are not seen/measured identical from different frames, so why this time v'=v? [This question is addressed to all the participants in this thread, not just to Jan Slowak.]
  11. After I wrote the above (something you may have considered redundant/obvious) I wondered why v is the same, I mean when x' = 0, x = vt but when x = 0, x' should be -v't'. Why v' = v ?
  12. In the above quote (with y = mx + b) you are right, those two problems have nothing in common, but in the first quote (with x' = Ax + Bt) the "problems" are not independent, they are about exactly the same thing seen from different perspectives (different frames). When x' = 0, x must be vt, because at t=0, x' = x = 0 and the "x' frame" moved with the speed v. In the "Special Case 2", where x = 0, x' must be -vt', for the same reason. This is not random as in your example (SC1: x = 0, y = 5 and SC2: y = 0, x = 0). [I'm not absolutely sure that all I wrote is correct, but I think it may help.]
  13. So I need to buy the above article in order to see how you(?) explain the Sagnac effect through optical fibers, where the speed of light is c/n?
  14. If it really is "global/generalized", you must also take into consideration (and deal with) the cases where n, the refractive index, is greater than 1 (e.g. when light is traveling through optical fibers, with the speed c/n). Did you? Maybe it is (as I wrote in this here forum), but it is very well explained using special relativity, as you can see here.
  15. Few indications towards my approach are mentioned in my Fizeau/Sagnac explanation. Maybe we should move & continue the discussion there, although I think it can wait. By the way, the F/S explanation is valid, no matter who (the electron in the atom or the atom/molecule as a whole) does the "absorption"+emission. Maybe I'll get back to this subject and answer your questions in a dedicated thread (my theory about the nature of light), but only when I'll finish with the main subject here. Regarding the above discussed proprieties/behavior of DM particles, take them as defined like that. If the theoretical tests I mentioned above will confirm my predictions, then I'll get back to the subject. Until then it would be a waste of time. As I said to Strange, let's wait for my new input (theoretical tests). Maybe they'll prove me wrong ...
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