Sunset and sunrise?

Question

What causes the colours of the sunset?

Answer 1

sunset


A composite image showing the terminator dividing night from day, running across Europe and Africa. Observers on the surface of the earth along this terminator will see a sunset.


Sunset, also called sundown in some American English dialects, is the time at which the Sun disappears below the horizon in the west. It should not be confused with dusk, which is the point at which darkness falls, some time after the beginning of twilight when the Sun itself sets.


The red hues of the sky at sunset and sunrise are caused by Mie Scattering, not Rayleigh Scattering. The colours of the sky throughout the day and at sunrise and sunset, are explained by the phenomena of both Rayleigh Scattering and Mie Scattering. The colour of the sky described by Rayleigh Scattering applies to the hues of blue, violet and green, not to the reds, oranges, peaches and purples of sunrise and sunset. Rayleigh Scattering is scattering of shorter wavelength light (e.g. blue & violet) by air atoms and molecules (not statistical variations in density of the Earth's atmosphere). The magnitude or strength of Rayleigh Scattering varies by the reciprocal of the wavelength raised to the fourth power, and hence does not explain the beautiful variations of reds, purples, oranges and peachy colours. The latter colours arise from Mie Scattering, low angle scattering of light off dust, soot, smoke and (ash) particles. Mie Scattering (producing the colours of sunset and sunrise) is beautifully recognizable down-wind of and after dust storms, forest fires and volcanic eruptions that inject large quantities of fine particulate matter into the atmosphere. A number of eruptions in recent times, such as those of Mount Pinatubo in 1991 and Krakatoa in 1883, have been sufficiently large to produce remarkable sunsets and sunrises all over the world. Sometimes just before sunrise or after sunset a green flash can be seen.

http://www.answers.com/sunset%20

sunrise
Sunrise, also called sunup in some American English dialects, is the time at which the first part of the Sun appears above the horizon in the east. Sunrise should not be confused with dawn, which is the (variously defined) point at which the sky begins to lighten, some time before the sun itself appears, ending twilight. Because atmospheric refraction causes the sun to be seen while it is still below the horizon, both sunrise and sunset are, from one point of view, optical illusions.

http://www.answers.com/sunrise

Answer 2

When the sun is directly overhead, the sunlight has to only
pass through a few miles worth of thick atmosphere. But when the
sun is close to the horizon (at sunrise or sunset) the light goes
a much longer distance through the atmosphere. This causes
attenuation of the shorter wavelengths (blue - this is why the
sky is blue at other times of the day) leaving only the longer
wavelengths like orange and red to reach us. Having clouds in
the sky and a variety of other atmospheric effects also contributes
to the play of colors.

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 following article from the National Oceanic & Atmosphereic Administration can explain it better than I can (and with pictures!)

THE COLORS OF TWILIGHT AND SUNSET
http://www.spc.noaa.gov/publications/corfidi/sunset/

Answer 5

The angle that the light hits the surface and filtering of wave lengths. So as the sun rises, the sky turns red because of the long wave length as it continues to rise the wave length shortens and turns to blue to repeat the process in reverse during sun set. The variations of colors are due to humidity and other chemicals in the atmosphere so you get variants of blue or red or whatever running through the visible spectrum.

Answer 6

the atmosphrere and clouds as the earth rotates on it's axis..it can have different colors around the world as the clouds are almost never the same in 2 places at one time..