I know that scientists attribute the blue color of the clear sky to Rayleigh scattering. However, I have my own new theory that I entitled "Attiyah's blue sky". "Attiyah's blue sky" theory has seven main hypotheses.
(1) The blueness of the sky is due to two major factors: the blue color of ozone, and the blue emissions of the global daytime auroras; and to three minor factors: Rayleigh scattering, the noctilucent clouds and argon gas.
A- The blue color of ozone gas in both the stratosphere and mesosphere is the first major factor that can account for the greatest portion of the blueness of the sky.
B- The second major factor that contributes considerably to the blueness of the sky is the blue emissions of the global daytime auroras.
C- Rayleigh scattering, noctilucent clouds and argon gas contribute slightly to the sky blueness.
(2)The blueness of the sky concerns four atmospheric layers: the troposphere, the stratosphere, the mesosphere (including the ionospheric D-layer) and the ionospheric E-layer.
First, regarding the troposphere:
A- Its contribution to the blueness of the sky is almost slight. This slight contribution is largely due to Rayleigh scattering. This contribution gives the troposphere only very faint blue appearance.
B- Its variable contents affect the vividness of the blueness of the overlying atmospheric layers or conceal it.
Second, regards the stratosphere:
A- The blue color of the stratospheric ozone is the main contributor to the sky blueness of the sky as viewed from on the ground or outer space.
B- The ice of the stratospheric clouds such as the nacreous clouds has a minor contribution.
C- Argon atoms have a very minor contribution.
D- Due to the presence of different molecules other than ozone molecules, Rayleigh scattering plays a minor role.
Third, regarding the mesosphere (including the ionospheric D-layer):
A- The diurnal, global auroras in the D-layer continuously emit some blue spectra. B- The electric discharges relevant to the occurrence of auroras lead to the production of the ozone of the upper ozonosphere. This ozone content contributes significantly to the blueness of the sky.
C- The ice of the noctilucent clouds has a minor contribution.
Fourth, regarding the ionospheric E-layer:
The auroras that occur in the daytime E-layer give blue light globally and continuously.
(3) The main effect of Rayleigh scattering is not played on the blue waves in the direct solar light, but instead it is played on the main blueness of the sky that is due to the blue color of the ozone molecules in both the stratosphere and mesosphere, and to the blue emissions of the continuous daytime auroras, especially of the lower ionosphere.
(4) With respect to the Earth-stationed observers, the main effect of Rayliegh scattering on the atmosphere, particularly on the troposphere i.e. on the substratospheric gases, is not the enhancement of the apparent heavenly blueness, but instead this main effect is the dilution of the blueness.
(5) The dilution of the apparent blueness of the sky caused by Rayliegh scattering is directly proportional to the length of the line of sight in the troposphere.In other words, the dilution of the apparent heavenly blueness increases from overhead towards horizon.
(6) The dilution of the blueness of the stratosphere almost helps uncover the ionospheric layers overlying it. At the same time, the blue auroral emissions from the lower ionosphere decrease greatly.
(7) The orange or red horizons at sunset and sunrise are almost due to the orange and red emissions from the daytime auroras. These red and orange emissions of the auroras in both the lower and upper ionospheric layers, can outshine the Rayleigh-scattering-diluted blueness.
Were Rayleigh scattering the main cause of the blue appearance of the sky, the blueness should be nearly restricted to the troposphere, because about 80% of the Rayleigh scattering gases are present in it. However, when seen from the planes that fly in the highest regions of the troposphere, the troposphere itself does not show the familiar blue appearance of the sky. As well, the photos taken for the troposphere from satellites and space shuttles do not show it having the normal blue appearance of the sky as viewed from on the ground or from the outer space.
In addition to, one can see the normal blueness of the sky above the troposphere through the gaps between the clouds that are formed at the highest level of the troposphere itself. Even if the highest levels of the troposphere are full of white cirrus clouds, the troposphere under them does not seem blue. Moreover, astronauts did not give any reports about seeing a blue troposphere especially over the parts of the land far from the vast oceanic waters.
Argon gas is about one percent of the atmospheric composition.
Edited by attiyah zahdeh, 23 February 2008 - 12:10 PM.