Why is the sky green?

Question

I'm not wearing green-tinted shades, I'm not on Mars, and I'm perfectly sober.

Sunshine G, this is a natural phenomenon. I know what it is, but I'm seeing if others know. I don't think it'll be a dumb question the next time your sky is green, and you see what's going on up there!

One last detail: I know precisely what this is, and it isn't aurora borealis/australis. It has nothing to do my mental health and everything to do with dramatic summer weather, and the angle of the sunlight in relation to the viewer (who should be getting ready to seek shelter).


I'm disappointed in you Weather people. This question should be rather easy to answer. The people in P/S have answered this same question several times over, and supposedly those P/S regulars are dumber than dumb. No wonder why people dump all their questions on P/S!

Oh well. First person who answers this question correctly gets the "ten" plus any thumbs-up included with my own thumb-up.

Answer 1

One answer is that it is green because you are on the planet Altair 4 in the movie "Forbidden Planet."

Another answer is that there are cloud conditions that can filter out the blue light without lowering the overall light level very much. When this happens, the other colors near the blue end of the visible spectrum will become visible. This includes green.

It usually happens when the pre-cyclonic cloud form called a "wall cloud" gets between the observer and the sun. It can happen at any time of the day, but it is usually a phenomenon of the late afternoon.

Tornado researchers consider "going green" to be an indication of an imminent tornado in the vicinity.

Answer 2

With the sun up in the sky it appears blue, as the sun sets the sky can go through a series of reds, oranges, yellows, pinks etc. If it were possible to see beyond the horizon the next colour the sky would turn is green.

The reason for this change of colours is that light from the sun is scattered by the particles that make up the atmosphere, it's known as Rayleigh Scattering.

As the sun dips towards the horizon the sun light reaches the observer at an increasingly more obtuse angle and has to pass through more of the atmosphere before reaching the observer. The more atmosphere the sunlight passes through the more it is scattered and it's these different levels of scattering that cause the sky to appear different colours.

From time to time there are atmospheric anomolies and in the days and weeks following major volcanic eruptions there can be all sorts of weird and wonderful scenes played out in the skies. It's the particulate matter ejected by volcanoes into the atmosphere that cause these unusual sights.

Similarly if there's been large scale sand or dust storms this will put a lot of particulate matter into the atmosphere. These storms don't need to be local, the dust can be carried thousands of miles. It could be caused by more localised events, if there's are wildfires or there's been an industrial accident, these events can put pollutants into the atmosphere that change it's appearance.

If the green sky was low on the horizon shortly after sunset it could have been a type of mirage you saw, the actual green sky would be below the horizon but the bending of lighwaves could have made it appear above the horizon.

If it was during the day the most likely explanation is some form of pollution or particulater matter. It could also be caused by excessive amount of water vapour. When seen during the day it's often a prelude to bad weather. There are other reasons for green skies during the day but their causes aren't clearly understood.

If it was more of an incandescent sky with other colours besides green then it was popssibly the result of ice crystals in the atmosphere.

If it was at night it could have been the aurora borealis.

Here's some pics of green skies...
http://en.wikipedia.org/wiki/Aurora_(astronomy)
http://www.spacew.com/gallery/image003827.html

Answer 3

The sky isn't blue because of the fact it reflects the sea; despite if there's a splash mirrored image happening. The sky is blue, because of the fact the blue wavelength would not bypass for the time of the ambience like the purple and the yellow wavelengths do, despite if it gets 'bounced around' from molecule to molecule interior the ambience (the the main suitable option tern is 'Rayleigh scattering'), until it reaches us on the floor; so it variety of feels as though the blue is coming from everywhere, and the sky seems blue. At sundown; the blue gentle has been scattered away, and we then see the purple and yellow hues of the sundown. for the time of tornadoes; some thing comparable is known to happen: The purple and the yellow have handed for the time of the sky, and the many of the blue has been scattered away, so all what's left is a blue-green tinge.

Answer 4

Similar reason to why the sky is blue. It is based on the angle at which the light reflects off our atmosphere and any impurities such as dust, volcanic ash or clouds that may exist. Green skies maybe associated with tornadic activity, with a wall cloud, but more commonly, green will appear at dawn and dusk. Unlike other times of the day, the angle of the sun is too high and only blue prevails. At these specific times where the sun is just rising or falling below the horizon, the angle is more flat allowing green and other colors to pass through. There are some instances of a green flash, which happens the exact instant the sun rises or falls between the horizon.

Answer 5

The white light from the sun is a mixture of all colors of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colors and so form a spectrum. The colors of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of color receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our color vision.
Usually a clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colors because the blue light has been scattered out and away from the line of sight.
Probably because of pollution, you are only seeing the green, yellow and blue spectrums causing the sky to be perceived by your eyes as being green.
Hope this has helped and has put your mind at ease.

Answer 6

Is the weather bad where you are? Many times, when conditions are ripe for tornadoes, the sky will turn a weird green color. I always know when I see it that I need to be ready to take cover.

Answer 7

Why is the ocean purple? Or the clouds yellow? Or the grass, bright blue? Like the Tootsie Roll Pop conundrum, the world may never know.

Answer 8

In a weather-spotter training class I took, they said it was the light refracting (I think it was refracting,maybe reflecting) off hail; often the precursor of a tornado.

Answer 9

but it is a fun orange sky my dear :)
look out again and stop over doing that spinach of yours
Popeys been a bad influence to you :P

Answer 10

why is the sky blue?

we don't know!

jk,... i seriously don't know ^^