Light and Vision: Photon Direction

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Discussion Overview

The discussion revolves around the behavior of light as it disperses from a point source and how the human eye differentiates between multiple light sources in its field of view. It explores the interaction of light with the eye's anatomy, particularly focusing on the role of the lens and the retina in processing visual stimuli.

Discussion Character

  • Conceptual clarification
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions how the eye can differentiate between light from multiple point sources given that photons disperse in all directions.
  • Another participant suggests that the lens of the eye converges light from each point source to a single point on the retina, aiding in differentiation.
  • A participant reiterates the concern about photons from two close light sources potentially striking the same photoreceptor cells, seeking clarification on the directionality of light transmission through the eye.
  • Further discussion includes the idea that the angle of incoming light rays helps identify their source location in the visual field.
  • One participant expresses understanding after the discussion, indicating a grasp of the concepts presented.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the eye's ability to differentiate between light sources, with some proposing explanations while others seek further clarification. The discussion does not reach a consensus on all points raised.

Contextual Notes

Some assumptions about the behavior of light and the eye's processing capabilities remain unaddressed, and there are unresolved questions about the interaction of light rays from multiple sources.

clalburn1420
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How is it that light disperses from a point source (like a pinhole w/ a light shining through). From my understanding, photons disperses in all directions at all angles. So than how is it that an eye can differentiate that point from all the other points light around it (say there was another pin hole in a different area of the field of view). Would not the complete dispersal from one point of light hit every photoreceptor cell? And if so, how would it differentiate that stimulus from another point of light?
Thanks very much.
 
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That's what the lens of the eye is for. It converges the light from each point source to a single point on the retina.
 
clalburn1420 said:
How is it that light disperses from a point source (like a pinhole w/ a light shining through). From my understanding, photons disperses in all directions at all angles. So than how is it that an eye can differentiate that point from all the other points light around it (say there was another pin hole in a different area of the field of view). Would not the complete dispersal from one point of light hit every photoreceptor cell? And if so, how would it differentiate that stimulus from another point of light?
Thanks very much.

It is the angle of the rays coming in to your eye that identifies the direction to you.

Think about what you're seeing right now. There's a light ray coming from a window in your peripheral vision. It impinges on your eye near the edge of your cornea and directed into your pupil where it impinges on your retina way over near the edge. A stimulus received at that point on your retina appears in your vision as a source of light in your preipheral vision.
 
Still not sure i understand. Let me try illustrating my understanding, and then correct me one how terribly misinformed i am.

In the attachment i did a rough representation of what I'm talking about. If two points of emitting light are next to each other and near the eye, won't their photons be crossing paths, eventually striking same receptors?
I mean, one point of light does not transmit through the eye in only one direction/angle, does it?
 

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clalburn1420 said:
I mean, one point of light does not transmit through the eye in only one direction/angle, does it?
The purpose of a lens component is that it takes divergent rays coming from a single distant source and focusses them at a point.

See diagram.
 

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Last edited:
I think i get it. Thats pretty amazing. Thanks very much!
 

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