10-01-2003, 11:55 PM | #2 (permalink) |
Cracking the Whip
Location: Sexymama's arms...
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The sky is blue because at most (steep) angles during the day, the sun's light refracts(splits out) blue light. During sunsets when the angle is steeper, red light is refracted more, hence red sunsets.
Edited to say: Sorry, I got the mechanism wrong, it's technically Rayleigh or coherent scatter (yes, there is an incoherent scatter called Compton scatter.
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"Of all tyrannies, a tyranny exercised for the good of its victims may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end, for they do so with the approval of their own conscience." – C. S. Lewis The ONLY sponsors we have are YOU! Please Donate! Last edited by Lebell; 10-04-2003 at 01:25 AM.. |
10-02-2003, 10:28 PM | #4 (permalink) |
‚±‚̈ó˜U‚ª–Ú‚É“ü‚ç‚Ê‚©
Location: College
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When you look at a random piece of sky, you're seeing light that is being emitted by gas molecules in the atmosphere. They are radiating light in all directions, including towards you. The energy for this comes from sunlight that they absorb. Because they tend to absorb short-wavelength blue light more than longer wavelength light, their radiation is also blue.
The ocean is a little more complicated... First, as you mentioned it reflects the blue light from the sky. Second, just as the gas molecules absorbed and redirected blue light towards you, water molecules in the ocean will do the same thing. Also, the ocean contains microorganisms that are blue-green and contribute to the color. |
10-03-2003, 01:50 PM | #5 (permalink) |
Upright
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Not to be annoying, I'm just pondering but why are clouds white? And, more importantly, why can't you see into space during day, but spaceships can see water and (green) land during day. The atmosphere blocks most of the light coming in, so why would green earth be more visible than other reflections when coming back out. Why don't you see predominately (often red) auroras and other reflections. And I know this may sound stupid, but I just realized that the blue sky isnt high in the sky, its right in front of your face as well. Actually thinking about this I may have answered my own questions, but if you have anything to add, feel free
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10-03-2003, 02:10 PM | #6 (permalink) |
‚±‚̈ó˜U‚ª–Ú‚É“ü‚ç‚Ê‚©
Location: College
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The problem with seeing into space during the day is that the tiny amounts of light coming in from the stars are greatly overwhelmed by the amount of sunlight being reflected by the atmosphere. Sometimes you can see the moon during the day because there's still enough light intensity there to be noticed. On the other hand, there's lots of light reflected off the earth into space, so although a spaceship would get the blue scattering, that would be overwhelmed by light reflected directly from the ground.
In other words, the atmosphere is not blocking light, it is reflecting it. The blue sky is really thick, so although the air in front of you is technically reflecting a small amount of blue light at you, most of that light is coming from the miles of air beyond the air that's really close to you. I don't know about clouds and specifically why they would be white if the ocean is blue. |
10-03-2003, 09:32 PM | #7 (permalink) |
Crazy
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Its because of the composition of our atmosphere. Our atmosphere acts like a filter and only reacts to rays of a certain wavelenght. In our case, blue rays are relected on the sky which gives it its blue color. On other planets, sky can be of a different color depending on its atmosphere. On mars, the sky is red. On venus, its yellow is a remember correctly.
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10-04-2003, 01:33 AM | #8 (permalink) |
Cracking the Whip
Location: Sexymama's arms...
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It's NOT reflecting, it's NOT filtering.
It's scattering. The mechanism is the selective absorption and re-emmision of blue wave electromatic radiation (from sunlight) by the gases that compose or atmosphere. This phenomon is known as Reyleigh scatter. You can't see the stars because the blue light "haze" is brighter than they are. Whereas, reflected light from the surface is plenty bright enough to be seen through the atmosphere light "haze" from space.
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"Of all tyrannies, a tyranny exercised for the good of its victims may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end, for they do so with the approval of their own conscience." – C. S. Lewis The ONLY sponsors we have are YOU! Please Donate! Last edited by Lebell; 10-04-2003 at 01:36 AM.. |
10-06-2003, 11:34 AM | #9 (permalink) | |
Bokonist
Location: Location, Location, Location...
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Quote:
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blue, makes, sky or ocean |
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