Why do some parts of the sky appear more yellow during sunrises and sunsets?

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Discussion Overview

The discussion revolves around the phenomenon of color variation in the sky during sunrises and sunsets, particularly focusing on the appearance of yellow hues in certain areas. Participants explore the underlying physics, including Rayleigh scattering and other related optical effects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant inquires about the beams of light in a provided image, expressing interest in their properties.
  • Another participant suggests that the beams are not real but rather manifestations of lens flare caused by the camera or eye.
  • There is a mention of the "green flash" phenomenon as an interesting aspect of sunrises and sunsets, with links provided for further reading.
  • One participant shares a personal anecdote about missing the green flash due to an obstructing ship, highlighting the anticipation surrounding this event.
  • Another participant introduces the concept of anticrepuscular rays as an interesting optical phenomenon related to sunrises and sunsets.
  • A question is raised about why some parts of the sky appear more yellow than others during sunrises and sunsets, despite the expectation that all light would scatter equally.
  • Responses indicate that variations in scattering occur due to differences in the amount of air and distance light travels, suggesting that clouds at different heights can scatter light differently.

Areas of Agreement / Disagreement

Participants express curiosity and share insights about the phenomena, but there is no consensus on the specific reasons for the color variations observed in the sky during sunrises and sunsets. Multiple viewpoints and explanations are presented without resolution.

Contextual Notes

Participants acknowledge that while simplifications can be made regarding scattering, real-world conditions such as varying distances and heights of clouds complicate the scattering process.

Lifed
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Hello everyone!

It's my first time here, so I hope everything is appropriate and I apologize if it isn't. I'd like to know if anybody has any information about these beams of light shown in the image below:

i46.tinypic.com/qqohvp.png

If anyone knows what they're called or what property of light they are caused by it would be incredibly useful for me, as I'm super interested. Also they're gorgeous.

Well, the image tags didn't work, but there's the link. I promise it's not spam
 
Last edited:
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They aren't real beams of light, they are various manifestations of lens flare. Its the mechanism of the lens in the camera/eye that creates these false images, they aren't actually there.
 
Aha, interesting. Even though they're artificial they're still awesome.

Since you seem to be rather knowledgeable, I have another question if you don't mind. Is there any cool physics related stuff to do with sunrises besides the typical Rayleigh scattering?
 
Aw man, if I could get a picture of a green flash it would probably be the greatest moment of my life. Thanks man.
 
I was in Honolulu down on Waikiki Beach, Hawaii some years back
we were all down on the beach waiting for the green flash as the sun set over the ocean horizon.

RIGHT at the time it was going to happen this huge tanker ship sailed across the horizon right in front of the setting sun. As you can imagine there were dozens of us with cameras at the ready totally disappointed at not seeing the flash :(

maybe another time :)

Dave
 
Lifed said:
there any cool physics related stuff to do with sunrises besides the typical Rayleigh scattering?

for sunrises and sunsets look in the opposite direction for the shadow of the horizon as it moves over the landscape.
another cool one seen from time to time are anticrepuscular rays ... have a look at the link below :)

anticrepuscular rays

they can also be good to photo

cheers
Dave
 
Wooh! You guys rock. I have one more question, to do with Rayleigh scattering. I've noticed that in a lot of sunrise/sunset pictures some parts of the sky or clouds appear more yellow than the sunrise. Wouldn't, since all of the light is traveling the same distance to my eyes and therefore are scattered the same amount, everything I see be the same wavelength and as such the same color?
 
The thing is you can approximate everything by saying all clouds are the same and all air is the same so it will all scatter equality, but in reality somethings are a bit different than others and will scatter differently.

To further this, the more air in between the light source and you, the more the light is going to get scattered. This is why sunsets are colorful, and it also is responsible for smaller distortions.
 
  • #10
Lifed said:
Wooh! You guys rock. I have one more question, to do with Rayleigh scattering. I've noticed that in a lot of sunrise/sunset pictures some parts of the sky or clouds appear more yellow than the sunrise. Wouldn't, since all of the light is traveling the same distance to my eyes and therefore are scattered the same amount, everything I see be the same wavelength and as such the same color?

Clouds at a different height and different distance from you can appear to be in the same direction. (Draw it out and it becomes obvious). This means that the path length of light passing through clouds which appear to be in the 'same place' can be different and subject to different amounts of scattering - hence their colours may look different.
 

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