Why does light diffraction create circular patterns?

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Discussion Overview

The discussion centers on the phenomenon of light diffraction and its role in creating circular patterns observed when sunlight passes through gaps in tree leaves. Participants explore the reasons behind the circular shape of these patterns and the conditions under which they are visible.

Discussion Character

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

Main Points Raised

  • Some participants note that circular patterns are observed when sunlight passes through gaps in leaves, questioning why these patterns are circular rather than other shapes.
  • One participant suggests that the diffraction pattern is influenced by the size and shape of the aperture, referencing external sources for further reading.
  • Another participant argues that in daylight, the gaps act as pin-hole lenses, projecting images of the solar disk, which is circular.
  • A later reply mentions that during an eclipse, the circular patterns transform into crescents, indicating the projection of the sun's shape.
  • One participant shares a personal experience of observing ring-shaped shadows during an annular eclipse, attributing the effects to atmospheric conditions and the eclipse's geometry.
  • Another participant confirms the observation of circular projections and inquires about a formula to calculate the size of the expected image based on distance from the aperture.

Areas of Agreement / Disagreement

Participants express varying views on the visibility of diffraction patterns in daylight and the role of pin-hole effects. There is no consensus on the exact mechanisms or conditions that lead to the observed circular patterns.

Contextual Notes

Some claims depend on specific conditions such as daylight or eclipse scenarios, and the discussion includes references to personal observations that may not generalize universally.

Who May Find This Useful

This discussion may be of interest to those exploring optics, light behavior, and phenomena related to eclipses and natural light patterns.

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TL;DR
We see under trees circular light that goes from sun through the leaves gaps. Why does it create a circular shape and not other shapes? why does this diffraction phenomenon create it in circular patterns?
We see under trees circular light that goes from sun through the leaves gaps. Why does it create a circular shape and not other shapes? why does this diffraction phenomenon create it in circular patterns?
 
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Can you upload a couple pictures of what you are seeing? Use the "Attach files" link below the Edit window to upload a PDF or JPEG image.

The diffraction pattern will depend on the size and shape of the aperture. See the Wikipedia article for a good introduction to diffraction:

1708104457111.png

https://en.wikipedia.org/wiki/Diffraction
 
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In daylight conditions, sunlight passing through gaps in the leaf cover will not produce readily visible diffraction patterns.
But those gaps will act as pin-hole "lens"s. So in the shadow of the canape you will see projected images of the solar disk - which is circular.
 
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.Scott said:
But those gaps will act as pin-hole "lens"s.
I can attest to this because during an eclipse the circles turn into crescents. You are seeing a projected image of the face of the sun. There is an eclipse here on 8 april ......I will report
 
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I was living in Virginia during the 1984 annular eclipse. Hence ring-shaped shadows. Although we had clear skies, atmospheric effects combined with the annular shape to create some really weird lighting effects.
 
.Scott said:
In daylight conditions, sunlight passing through gaps in the leaf cover will not produce readily visible diffraction patterns.
But those gaps will act as pin-hole "lens"s. So in the shadow of the canape you will see projected images of the solar disk - which is circular.
Yes, this is exactly what I observe. Also, the size of the image varies with the distance from the aperture. Is there a formula for calculating the the size of the expected image for a given distance?
 

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