What is the scientific reason the sky is blue?

Question

I found out the reason pretty intresting, do anybody else know!

Answer 1

The blue color of the sky is caused by the scattering of sunlight off the molecules of the atmosphere. This scattering, called Rayleigh scattering, is more effective at short wavelengths (the blue end of the visible spectrum). Therefore the light scattered down to the earth at a large angle with respect to the direction of the sun's light is predominantly in the blue end of the spectrum.

The strong wavelength dependence of Rayleigh scattering enhances the short wavelengths. Intensity is INVERSLY proportional to fourth power of wavelength.

Note that the blue of the sky is more saturated when you look further from the sun. The almost white scattering near the sun can be attributed to MIE Scattering, which is not very wavelength dependent.

Clouds in contrast to the blue sky appear white to achromatic gray.The water droplets that make up the cloud are much larger than the molecules of the air and the scattering from them is almost independent of wavelength in the visible range

Answer 2

Forget the atmosphere for a moment and just imagine a single electron, a red photon (which has little energy) and a blue photon (which has a lot).
A blue photon has nearly enough energy to lift an electron to a higher energy state, but it doesn't have quite enough so it borrows the extra energy needed from nothing at all (really, energy is borrowed from nothing !!!). But, Mother natures rule for borrowing energy is "the more you borrow the sooner you have to give it back". So now we have an electron in a high energy state due to the energy from the blue photon and the borrowed energy. Because only a little bit of energy was borrowed (remember the rule) it can stay in this state for quite a long time before mother nature asks for her energy back. When that happens the blue photon is "kicked back out" of the electron.
The key point is that the electron is part of an atom (specifically a Nitrogen atom in the atmosphere) and that atom is spinning so it can turn quite a long way round in the time between when the blue photon was absorbed (by the electron) and emitted. The practical upshot of which is that the blue photon approaches the atom from one direction but departs in a very different direction or is "scattered". So all blue light is scattered from Nitrogen atoms in the atmosphere so the sky appears blue. Voila !

In order fopr a red photon (less energy) to boost an electron to a higher level it must borrow a lot of energy and so has to pay it back sooner. That means the atom won't have turned very far before the red photon is fired out again. So its fired out in pretty much the same direction as it arrived.

Its a bit like jumping on a a merry-go-round. If you stay on for a few seconds, when jump off you'll be travelling in a completely different direction. If you jump on then straight off you'll be travelling in pretty much the same direction as when you jumped on.

Answer 3

Everyone likes to label it as Rayleigh Scattering but still very few explain that term. The Sun emits pure white light. As the sun comes up or sets, the light has more air molecules to travel thru, giving a longer bend to the white light, the reds having a longer frequency, and due to the longer bend of the light from the amount of air, we see reds at sunrise and sunset. AS the Sun climbs higher, it goes thru less air to get to ours eyes. Hence the light is not refracted as much, less bend you might say, blues have a shorter wavelength, so we see blue. Notice on clear cloudless days, the sky is real blue in the middle around noon and appears whitish at the horizon. We are looking at light traveling away from us at the horizon so we see the white light as from the sun. On cloudy or foggy days, less blue because the white light is being filtered by the greyness of the clouds or fog.

Answer 4

The sky isn't blue all the time. It has to do with the light from the sun on the curvature of the earth. That's why sunsets/run rises are red,yellow and orange skies. If you look straight UP the sky is actually navy blue on a clear day. It's about curves baby!

Answer 5

Kelsey reported the earth is roofed by skill of ninety% water. incorrect. the actual volume coated by skill of all water is barely seventy one%. the sea isn't the reason the sky is blue. What have been you thinking and the place do you get your suggestion? Donald Trump?

Answer 6

The sky is black. It just looks blue because all the red color from the sun's white light is scatterd.

Answer 7

Because if it were green, you wouldn't know when to quit cutting the grass.

Answer 8

http://answers.yahoo.com/search/search_result;_ylt=Aq.qXs07BL7KLU9qTVPLN4knzKIX?p=sky+is+blue

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I think they know now!