why is the sky blue during the day and black during the night?

Answer 1

To start of with we must understand what light is.

Light isnt just made up of 1 colour, it contains a number of different colours each of which has a different wavelength. Light is split up into the following colours with the first having the longest wavelenght and the last having the shortest.

Red
Orange
Yellow
Green
Blue
Indico
Violet

An easy way to rememeber this is ROY G BIV (my year 12 geology teacher taught me that about 8 years ago)

As light moves through the atmosphere, most of the longer wavelengths are able to pass straight through. Little of the red, orange and yellow light is affected by the air. However, much of the shorter wavelength light is absorbed by the gas molecules in the atmosphere which is mainly nitrogen (78%) and oxygen (21%). The absorbed blue light is then scattered in all different directions. Since you see the blue light from everywhere overhead, the sky looks blue.

On Earth, the sun appears yellow. If you were out in space, or on the moon, the sun would look white. In space, there is no atmosphere to scatter the sun's light. On Earth, some of the shorter wavelength light (the blues and violets) are removed from the direct rays of the sun by scattering. The remaining colors together appear yellow.

You didnt ask about sunsets, but what the heck :)

What happens during sunsets is that as the sun begins to go down, the light must travel farther through the atmosphere before it gets to you. More of the light is reflected and scattered. As less light reaches you directly, the sun appears less bright. The color of the sun itself appears to change, first to orange and then to red. This is because even more of the short wavelength blues and greens are now scattered. Only the longer wavelengths are left in the direct beam that reaches your eyes.

The second part of the your question is a lot easier. The sky is black simply because of the lack of light from the sun going through the atmosphere. If there are no colours from the spectrum to get absorbed then the only thing that is left is the blackness of the sky.

Answer 2

The hemisphere facing the sun gets more light, turning the black/blue sky of the universe lighter during day. The opposite of that happens during night, making it darker.

And the atmosphere spreads air and light around because if it didn't, one spot would be blue, the rest would be black.

Answer 3

Blue I believe due to the effect of oxygen and nitrogen atoms in the atmosphere 'knocking' the light rays about on their way through the atmosphere. Look up the Rayleigh effect for a detailed explanation. Why the night sky is black is more interesting. It is because the light of most of the stars in the sky is actually blocked by huge amounts of gas and dust in space. Without that gas and dust the light of billions of stars would be visible in the 'night' sky, and it would appear to us as an almost continuous 'sheet' of white light. Even as it is you can 'see' and read a newspaper by 'starlight'. Try it on a clear night in the country with the Milky Way high in the sky.

Answer 4

no longer the ozone!!!!!!! the colloidal debris! u see the sunlight is brighter than the moon.a ctually the moon seems purely borrwing mild potential from the sunlight so the area eher of the colloidal debris(airborne dirt and mud) is to bounce of light. because of the fact the spectrum which could be take in is the colour blue. apparently on day. yet throughout the time of night sicne the moon is purely week so we the colloids can not boucne to plenty mild so we see the main southern area of the spectrum this is indigo... seems black. attempt to holiday an airplane. u'll see the spectrum

Answer 5

The particles in the air, esp. water vapor, reflect sunlight in the blue spectrum. As you the sun gets closer to the horizon, its light has to go through more atmosphere, so other colors show up, (orange, red, yellow), due to atmospheric pollutants AND the angle at which they're viewed (like a rainbow). The more pollutants, the redder the light.

In areas like central New Jersey, where there are lots of airborne pollutants AND light bouncing of those and cloud cover, the sky is often ORANGE at night, not black!

Answer 6

The sun! The color blue is scattered more than red from sunlight by the atmosphere. As you go higher, say to the edge of space, the "sky" will be black even in sunshine. At night... no sunlight, so sky is black.

Answer 7

The reason it is blue during the day is the sunlight is bounced back to the atmosphere and all but the blue wavelength is absorbed. The reason it is black during the night is there is no sun shining.

Answer 8

Its blue during the day because the sunlight reflects off the elements of the atmosphere---nitrogen, oxigen, cafrbon dioxide, water vapor, etc.---altogether, it reflects blue light.
It's black at night because there's no significant light source like the sun to cause the atmosphere to reflect it brightly....and so, you can see outer space at night.

Answer 9

The space gnomes take the big blue curtain and turn in backwards to show the black side. It's got little white dots painted on it called "stars".

Answer 10

well its cause the earth rotates and at night the part that was facing the sun rotates to the other side leaving the moon!!! hence night and day!!