Does Light Have Advanced Knowledge of Denser Mediums Along Its Path?

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Discussion Overview

The discussion revolves around the nature of light as it transitions from a less dense medium to a denser medium, specifically questioning how light "knows" about the denser medium and whether it receives information regarding its path. The conversation touches on theoretical concepts, interpretations of Feynman's lectures, and the implications of wave equations in physics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants reference Feynman's explanation that light travels through all possible paths, with only the shortest-time path surviving interference, raising questions about non-local phenomena.
  • Others argue that the wave equation governing light's behavior is local, suggesting that no non-local information is necessary for understanding refraction.
  • One participant expresses uncertainty about the precise interactions of light and the concept of "information," suggesting that current insights are more like working rules rather than fully satisfying explanations.
  • Another participant connects Fermat's principle to Newton's first law, proposing that light, like other objects, tends to travel in a straight line unless acted upon by a force.
  • There is a mention of the aesthetic satisfaction some find in Maxwell's equations and their solutions, contrasting with the more ambiguous nature of current understandings of light's behavior.

Areas of Agreement / Disagreement

Participants express a range of views, with no consensus reached on how light interacts with mediums or the nature of information in this context. Some agree on the local nature of the wave equation, while others question the completeness of current explanations.

Contextual Notes

Participants highlight uncertainties regarding the interaction of light with different media and the implications of information theory, suggesting that definitions and interpretations may vary significantly.

spidey
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In Feynman lectures, Feynman says if light goes from air to denser medium,light goes more in air and less in denser medium so that it takes shortest time to reach its destination.

My question are

How light knows that there is a denser medium ahead in its path?

Does light get information about the denser medium?

what is information?
 
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Feyman's own explanation is that the light goes everywhere, but only the shortest-time path is not interfered away - in other words only the shortest-time path survives destructive inteference. This seems to require some non-local phenomenon to take place.
 
Mentz114 said:
Feyman's own explanation is that the light goes everywhere, but only the shortest-time path is not interfered away - in other words only the shortest-time path survives destructive inteference. This seems to require some non-local phenomenon to take place.

Yes, i understand shortest time path is the only one surviving..but how does light know its destination and making its path survive from interference? Does light get information about medium and destination?
 
spidey said:
Yes, i understand shortest time path is the only one surviving..but how does light know its destination and making its path survive from interference? Does light get information about medium and destination?
It doesn't. That was what Mentz114 just said.
 
Refraction is a general property of solutions to the wave equation in different media. The wave equation is purely local, therefore no non-local information is required.

You can certainly describe the solution in terms of a photon asking yahoo maps to plot it the optimal route, but you don't need to do that. The optimality automatically falls out of solutions to the purely local wave equation.
 
Spidey:
I'd say while it's experimentally known that light takes the least time path, in general the less dense medium, the precise interaction is one of many uncertainities/unknowns in physics. We have insights, as posted, maybe we can call them working rules, but they are not fully "satisfying".

As for "information", check out Wikipedia for an introduction. Entropy and thermodynamics can be considered as sub categories of information. In Claude Shannons information theory, a "bit" becomes the fundamental unit and in quantum theory, a qubit.

An interesting book is by Charles Sief: DECODING THE UNIVERSE,2006 (How the new science of information theory is explaining everything in the cosmos...)...even What is life? Does entanglement explain telepathy? and so on.
 
I think Fermat's principle comes from Newton's first law that " all objects in uniform motion tends to be in uniform motion"..so that objects reach their destination in straight line path in least time..For objects to take other paths, a force has to be applied and this will change its uniform motion and they cannot reach their destination in least time..same applies to Light as well..Light also travels in uniform motion and tends to travel in uniform motion..Is this correct?
 
Naty1 said:
We have insights, as posted, maybe we can call them working rules, but they are not fully "satisfying".
That is an aestetic judgement. I find Maxwell's equations, the resulting wave equation, and their solutions fully satisfying.
 

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