does any one know why is the sky blue?

Question

i have always wondered this can any one answere this Qs

Answer 1

OK - as far as know this is the 135th time this question has been asked on this site. So here is a cut and paste of the answer I gave last time - a pretty definitive one I think.

There are a number of factors which need to be considered when answering this question - 1. The physics of why a particular wavelength of light reaches your eye. 2. The way in which that light is translated into a colour by your eyes and nervous system. 3. The social aspect.

Here are my answers to each of those parts.

1. When the sun's light hits the earth's atmosphere and moves through it, most of the lower frequencies (longer wavelengths) pass through with little resistance. The higher frequency light (shorter wavelengths) however, is absorbed to a larger extent by the gas molecules. The absorbed light is then radiated in different directions and thus, gets scattered so that whatever direction you look in, some of this higher frequency scattered light reaches your eyes. This is known as "Rayleigh Scattering"

2. The human brain derives color by comparing the responses to light from three types of cone photoreceptors in the eye. These cone cells are sensitive to different frequency (or wavelength) ranges in the visible spectrum. In this case, the cone cells which are more sensitive to higher frequency light become more active than the others, and comparative responses of the cone cells gets translated into the colour associated with higher frequency light.

3. From the time we are born, we are taught names for our perceptions of different natural phenomena, i.e we are socially conditioned to call something we perceive by a specific name. In this case, the colour blue is what we are socially conditioned to call our brains response to the light that reaches our eyes through Rayleigh Scattering.

Thus, the sky is blue.

Answer 2

In spite of my high regard for the Nasa website and the answers they usually give to questions, I have to take exception from their answer on this one.

For this, you'll need to do an experiment.

Find some sort of clear glass rectangular container for liquids.. a fish tank will do nicely, but, you might not want to use it if you have any fish in it.

Fill if most of the way with pure water from the tap, or with distilled water, if you have it. The purer the water, the better.

Then, point a flashlight through it from one side to the other, so that the flashlight beam is pointed straight through the longest dimension of the container.

Look at the container from either side, and from the end. You'll probably not notice anything.

Then, add some milk to the water, enough to make it cloudy, the cloudier the better, but, if you put in too much milk, you will prevent the light from reaching the far side of the tank, so just start adding it gradually, and doing the same thing.

At some point you will begin to notice that light from the flashlight appears more blue from the sides, and more red from the other end of the tank.

That's because it isn't just ANY kind of particles that is responsible for the blue-light scattering, but, it's the Nitrogen that is in the protein molecules in the milk. Nitrogen is the same stuff that makes up more than 70% of the air we breathe, and it is Nitrogen that is responsible for causing blue light to scatter.

That's also the same reason that we have reddish/orangish sunrises and sunsets, is that the more Nitrogen of the more atmosphere that the sunlight has to penitrate to reach our eyes, the more of it's blue light has been bounced away by the Nitrogen in the atmosphere, leaving less blue light to reach our eyes, leaving more red and yellow light to reach our eyes.

Now this particular characteristic of Nitrogen isn't always that way. The nitrogen in amonia is a lot less likely to bounce blue light than the nitrogen in milk, and I don't really think you want a lesson on the quantum mechanics of nitrogen molecules in their various states, but, hopefully you can get the picture you make of it for yourself.

Just don't go about ruining your parent's favorite fishtanks for this experiment, or anything.

Answer 3

the blue colour of the sky is using Rayleigh scattering. As easy strikes in the time of the ambience, different the longer wavelengths pass rapidly via. Little of the crimson, orange and yellow easy is afflicted by employing the air. even regardless of the indisputable fact that, lots of the shorter wavelength easy is absorbed by employing the gasoline molecules. The absorbed blue easy is then radiated in distinctive instructions. It gets scattered everywhere in the sky. Whichever course you look, a number of this scattered blue easy reaches you. because you spot the blue easy from everywhere overhead, the sky looks blue.

Answer 4

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 5

Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.

Answer 6

I hav looked at all your answers but nobody has gave you any simple answer to ur question so here it is: The sky is not Blue it is in fact Black This is indeed caused by light refraction from the Sun When the Sun goes down at night we loose its light refraction and we get refraction from the Moon Thats why we see the Sky at night as Black enabling us to see the Stars: Thats the answer to answer ur question

Answer 7

I always thought it was because the atmosphere only allows the color blue to go through but that doesn't make any sense because then everything would look blue.
If other colors bounce off then why is it that the earth also looks blue from space?
But it does have something to do with the atmosphere.

Answer 8

Rayleigh scattering. Blue light hitting molecules in the atmosphere is more scattered than red light, so the red/yellow light from the sun goes straight to your eyes, and the blue light goes everywhere. The more atmopshere you look through, even green and yellow light get scattered, so that's why you see an orange/yellow sky at sunset and the sun looks redder. You're looking through more atmosphere at the horizen than overhead.

Answer 9

basically, the sky appears blue because the atmosphere bends the light from the sun to an angle that gives blue light.

Answer 10

some people think its because the sky reflects the sea but it's probably the sun relecting through particles in the air which create a blue sky. if not i dont have the foggiest