On an object's size vs distance relation

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Discussion Overview

The discussion revolves around the relationship between an object's size and its distance from an observer, exploring various theoretical frameworks to explain this phenomenon. Participants consider ray theory, Maxwell's electromagnetism, and Einstein's general relativity, with a focus on how these theories can be applied to understand apparent size without relying solely on ray theory.

Discussion Character

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

Main Points Raised

  • One participant suggests that ray theory explains why objects appear smaller with increased distance due to smaller angles, but questions how to explain this using Maxwell's theory instead.
  • Another participant introduces Einstein's general relativity as a framework that accounts for gravitational lensing, which affects the apparent size of distant objects.
  • A participant expresses concern that applying Einstein's relativity may be overly complex for objects at relatively short distances, suggesting a preference for Maxwell's electromagnetism.
  • One participant proposes finding a wave solution to Maxwell's equations and using wavelet theory to understand wave propagation, while noting that ray optics remains a useful tool.
  • Another participant emphasizes the goal of explaining the phenomenon independently of ray theory, acknowledging that geometric methods may converge on similar results.
  • Huygens' Principle is mentioned as a relevant concept that could assist in the explanation.

Areas of Agreement / Disagreement

Participants express differing views on the appropriate theoretical framework to use, with some advocating for Maxwell's theory while others suggest general relativity. There is no consensus on a single method for explaining the size/distance relationship, and the discussion remains unresolved.

Contextual Notes

The discussion highlights the complexity of applying different theories to a common phenomenon, with participants acknowledging the inherent geometric nature of the problem that may lead to similar conclusions across various methods.

davidge
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It's pretty easy to explain why objects appear small as the distance from them increases, if we use ray theory: as the distance increases, the angle become smaler. But I know the ray theory is far from being a accurate theory of light. My question is then, How can we explain the phenomenon of size/distance relation by using the next best theory of light that we have? I.e. using Maxwell theory

Just to say, I was driven to this question after reading about the Solar Eclipse that will occur later on this month.
 
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Say I want to explain the apparent size of objects that are some hundreds of meters away from me. In that case, I guess using Einstein's Relativity would be too hard as we are on a planet (Earth) with plenty of matter around us, etc... It would be definitely more easy to go with Maxwell's electromagnetism. The question then is, How do we proceed?
 
davidge said:
Say I want to explain the apparent size of objects that are some hundreds of meters away from me. In that case, I guess using Einstein's Relativity would be too hard as we are on a planet (Earth) with plenty of matter around us, etc... It would be definitely more easy to go with Maxwell's electromagnetism. The question then is, How do we proceed?
Find a wave solution to Maxwell's equations. Then use wavelet theory to see how waves propagate in straight lines. Then realize that ray optics is still a tool that gives correct answers.
 
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jbriggs444 said:
Find a wave solution to Maxwell's equations. Then use wavelet theory to see how waves propagate in straight lines. Then realize that ray optics is still a tool that gives correct answers.
Ok, that's great, but my goal on this thread is to find a way of explaining the given phenomenon independently of ray theory :frown:
 
Google for Huygens' Principle. It's basically step 2 in jbriggs444's plan.
 
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davidge said:
Ok, that's great, but my goal on this thread is to find a way of explaining the given phenomenon independently of ray theory :frown:
That is indeed what @jbriggs444 outlined. The "problem" is that the answer is inherrently geometric so pretty much any valid method will end up giving approximately the same result and looking a lot like ray theory.

It's like what happens when you apply General Relativity to low speed or static situations: it automatically simplifies to Newton's law of gravity whether you ask it to or not.
 
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Oh, ok. Thank you all. I will read something on the subject.
 

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