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Good greg 2004-03-16 11:16

it's an incredible colour - can anyone explain what makes it so blue?

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Old 03-16-2004, 07:03 PM
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Default To greg: The blue colour

Thanks for your comment Greg.


It because of the air imprisoned in the ice and compressed over thousand of year. It also depend on the light condition.

But I suggest you to read the message I wrote for Derek (quegarden) who was somehow asking the same question.
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Old 03-16-2004, 07:27 PM
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Default Re: To greg: The blue colour

Thanks very much for your answer. The other image is even better!

Even if there's air compressed into the ice, I don't see why it should get this colour - some kind of light scattering effect maybe, but why is it so different from common water ice? Intriguing...
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Old 03-16-2004, 07:32 PM
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Default The blue colour

ok, here's an answer from a USGS site:

Why are glaciers blue?

Because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the more blue it appears.

So... why is snow white?

Light does not penetrate into snow very far before being scattered back to the viewer. However, the next time you are in an igloo, notice that it is blue inside. You can also poke a stick into some snow, shade the area around the hole, and look deep into the snowpack. The light that has traveled some distance through the snow will be enhanced in blue.
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Old 03-16-2004, 07:39 PM
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Default Re: To greg: The blue colour

The compression change the structure of the water and air molecule. At one stage the ice reflect the blue even more. As reminder every object has for colour the wavelenght it can not absorb
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Old 03-16-2004, 07:43 PM
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Default Re: The blue colour

"The longer the path light travels in ice, the more blue it appears."

But you can see on the picture that blue is close to the surface of the ice. The compression and molecule modification must have a role in the the glacier's ice reflection of the blue wavelenght.
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