Debunking the Myth: The Truth About Sunlight and Color Scattering

[Holocene]

"Sunlight contains all colors. When light rays strike molecules in the atmosphere, some of the light bounces off in a new direction (scattering). The blue light is scattered more than other colors, so to our eye it seems to be coming from all directions, not just from the sun."

Isn't it the blue light that is scattered LESS than the other spectrums?

 

[Denton]

We percieve colours as its absence. A green leaf is due to it emmitting 'all' wavelengths but green.

 

[russ_watters]

The first is true, the second is not. For the sky, consider that if the blue light wasn't scattered, we wouldn't see it coming at us from all directions. For the perceiving colors by their absence, I'm not sure where you get that, but it isn't correct.

 

[GleefulNihilism]

We percieve colours as its absence. A green leaf is due to it absorbing 'all' wavelengths but green.

Fixed it for you.

 

[LURCH]

Blue and violet do indeed scatter more. They are high frequency, and behave like hyper children; bouncing all over the place. At short range, like when the sunlight is coming strait down throught the atmosphere, this makes the sky look blue because the blue light is all over the place. At greater depths like sunset (when sunlight is cutting through a lot more atmosphere), the scattering of blue light means that most of it is dispersed before reaching the ground, and the deeper-penetrating low frequencies (at the red end of the spectrum) dominate because they didn't get scattered as much.

 

[Dr. Keith]

Sunlight contains all colors.

This is not entirely true. If we refract sunlight we will notice that you don't get a perfect spectrum, some of the lines will be missing, this is true for all stars. However I think the sun has a fairly complete spectrum.

This is due to the nature of the gas that comprises the star

 

[dst]

This is not entirely true. If we refract sunlight we will notice that you don't get a perfect spectrum, some of the lines will be missing, this is true for all stars. However I think the sun has a fairly complete spectrum.

This is due to the nature of the gas that comprises the star

What frequencies are missing?

 

[Dr. Keith]

http://chinook.kpc.alaska.edu/~ifafv/lecture/fraunhofer.htm
I think the full image is at the bottom.

 

[Loren Booda]

Does the blue sky arise mostly from scattering off of relatively static air molecules, dynamic air molecules, or dust particles?

 

[Shooting Star]

We percieve colours as its absence. A green leaf is due to it emmitting 'all' wavelengths but green.

Quote:
Originally Posted by Denton
We percieve colours as its absence. A green leaf is due to it absorbing 'all' wavelengths but green.

Fixed it for you.

"We percieve colours as its absence." This sentence is still there? How did you fix it then ? We perceive green because it's the only one present...

 

[Shooting Star]

Does the blue sky arise mostly from scattering off of relatively static air molecules, dynamic air molecules, or dust particles?

Raleigh scattering takes place when 2pi*r/lambda <<1, where r is the characteristic dimension of the particle. For sunlight in air, the scattering particles are the Oxygen and Nitrogen molecules. The intensity of the scattered light is inversely proportional to lambda^4. So, the lower wave lengths, like the violet and the blue, scatter more.

There is an erroneous idea that dust particles or tiny droplets of water vapour can also cause Raleigh scattering, but their sizes are just too big. For them, the right treatment would be Mie scattering. The white colour of the sky near the sun can be treated according to the latter.