I Is There a Connection Between Rainbows and Holograms?

  • Thread starter Thread starter skynelson
  • Start date Start date
  • Tags Tags
    Rainbows
Click For Summary
The discussion explores the similarities and differences between rainbows and holograms, focusing on their optical properties. Both phenomena involve coherent light and wavefronts, but rainbows result from refraction and dispersion in water droplets rather than interference patterns, which are fundamental to holography. While some participants suggest there may be a conceptual link, others argue that the lack of coherent light in rainbows makes them fundamentally different from holograms. The conversation also touches on the mathematical aspects of both phenomena, with participants expressing skepticism about the relevance of comparing them. Ultimately, the consensus leans towards recognizing the distinct mechanisms behind rainbows and holograms.
  • #31
hutchphd said:
I believe these are sun dogs
I think what is shown is a halo. These are associated with sun dogs, which, afaiaa, are more describable as distinct images of the Sun. It's all the same sort of phenomenon and, because ice crystals have specific angles between faces, they tend to be seen at particular angles as the crystals mostly orientate in the same plane (floating down with the side face horizontal - like falling leaves), which localises the image. Perhaps the halo is due to very small crystals that do no orientate horizontally. The order of the colours seems to be that red is in the inner band - moving out to blue but there is a clear cyan band beyond. Cyan can be described as 'minus red' (i.e. green plus blue). That seems to imply that there is a much bigger range of dispersion than what spherical water drops produce.

Edit later - this is probably rubbish: I misinterpreted the video - but the video is still interesting. This Nasa link is interesting and can account for a lot of claimed UFO sightings. The sun dog seems to be zapping across the sky at amazing speed. Just what the enthusiast want to see!
 
Physics news on Phys.org
  • #32
hutchphd said:
I believe these are sun dogs
There are no sun dogs in that photo from Tom
 
  • Like
Likes Tom.G
  • #33
davenn said:
There are no sun dogs in that photo from Tom
True. It's a 'candidate situation' for sun dogs but the ice crystals are not aligned anywhere so all you get is a halo, from reflections at all angles in all places. To get a distinct image, a large proportion of the crystals need to be aligned (as I have read - horizontal like falling leaves) and that will produce a sharp reflection image.

Where I live in the UK I never see sun dogs, despite looking at the sky a fair bit. That's a shame but, with the prevailing winds from the West (Atlantic) , we do get some interesting clouds and cracking sunsets. Flat country and massive skys have their own charm.
 
Last edited:
  • Like
Likes hutchphd

Similar threads

  • · Replies 1 ·
Replies
1
Views
10K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
8
Views
8K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 21 ·
Replies
21
Views
5K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
7K
Replies
5
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K