How intimate are the rays of light?

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    Light Rays
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Discussion Overview

The discussion revolves around the nature of light rays emitted from distant sources, particularly focusing on the proximity of adjacent photons, the angles of their paths, and the implications of light emitted from point-like sources. The scope includes theoretical considerations and conceptual clarifications regarding light behavior in astronomy and optics.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants inquire about how close adjacent photons from a distant star can be to each other and whether their paths are parallel or at a minute angle.
  • One participant notes that rays from the sun are generally considered parallel, but acknowledges that the sun's size affects the angles of rays coming from different parts of it.
  • Another participant suggests that as a light source shrinks to a point, the emission of light resembles the radii of a sphere.
  • It is mentioned that photons, being Bosons, can occupy the same location, which raises questions about their paths and angles.
  • Some argue that while light rays from distant stars can be treated as parallel for imaging purposes, they actually shine in all directions.
  • A participant introduces the idea of a very small light source, like an electron, and questions when the divergence of its light rays would result in only one ray being observable in a telescope.
  • Another point raised is that the apparent parallelism of light rays is due to the vast distances involved, even though they are only approximately parallel in reality.

Areas of Agreement / Disagreement

Participants express various views on the nature of light rays and their behavior from different sources. There is no consensus on the implications of light emitted from point sources or the conditions under which rays become parallel.

Contextual Notes

Participants discuss the divergence of light rays and the conditions under which they can be considered parallel, highlighting the limitations of their assumptions regarding point sources and the nature of light emission.

nihilius
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1. Is there any clue as to how close two adjacent photons, coming from a distant star, in neighbouring paths, can be to each other?

2. Do their paths make a minute angle? or coming from a distance and heading towards earth, they are dead parallel to each other?

3. What, if the source of light is a distant powerful tiny mass, approaching a point in size? Shall we still be able to see parallel rays of light?
 
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The rays coming from our own sun are usually considered to be parallel, and the sun is not that far away considering the distance to other stars. But as you know the sun does take up certain arc in the sky, so a ray from the left side is not exactly parrallel to one coming from the right side.

For star light, since a star is light years away, that angle becomes smaller and smaller as you observe a star farther and farther away. Most stars look like point sources of light so the rays would be very very parallel.
 
Isn't that the case that as a source of light shrinks to a point, the emission of light resembles the radii of a sphere?
 
nihilius said:
1. Is there any clue as to how close two adjacent photons, coming from a distant star, in neighbouring paths, can be to each other?

They can occupy the same location as photons are Bosons.

2. Do their paths make a minute angle? or coming from a distance and heading towards earth, they are dead parallel to each other?

Depends on what you mean. When forming an image only light rays that are approximately parallel are used in a telescope. The actual light from the star shines in all possible directions and angles though.

3. What, if the source of light is a distant powerful tiny mass, approaching a point in size? Shall we still be able to see parallel rays of light?

Yes. That is how we view stars in most telescopes currently. They are so far away that they are very nearly a point source.
 
Drakkith said:
They can occupy the same location as photons are Bosons.



Depends on what you mean. When forming an image only light rays that are approximately parallel are used in a telescope. The actual light from the star shines in all possible directions and angles though.



Yes. That is how we view stars in most telescopes currently. They are so far away that they are very nearly a point source.



What you have mentioned is quite respectable but what I have in mind, when I say a point source is, actually, not a distant giant star (which is only a point from a distance) but something in order of, for example, and electron emitting powerful light enough to reach us from a long distance .As it gets farther and farther, the rays of its light become more and more scarce (because of their divergence).
The question is when will it come the point that you can only have one ray of light, say, in your telescope. It’s that happens there is an evidence (theoretically) that the reason we have parallel rays of light is that they are coming from an expanded surface.
 
Each "spot" on an image has been emitted from the same "spot" on the object. They are only parallel because of the great distance between us and the object allow us to consider them parallel even though they are only approximately parallel in reality.
 

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