The sky is red and blue. THE FINAL!

In the note “The sky is red-blue” 24 IV 2924, in the “Post Scriptum” to it, I gave, it seems to me, the final solution to all problems related to the blueness of the daytime sky, and its red color at sunrise and sunset.

In this appendix to the note, I gave the correct explanation, but a little unassembled, not clearly designed, so I decided to give again a final and exhaustive answer to all questions that may arise in connection with the specified colors of the sky.

First, let’s define three factors known in physics that by their nature could determine the color of the sky.

The first is the idea of the English physicist Tyndall: Fine dust hanging in the air

The second is the idea of the English physicist Ray: Air molecules.

The third is the idea of the Russian, and later Soviet, physicist Mandelstam: Fluctuations in air density arising from the chaotic Brownian motion of molecules.

All three ideas are based on several fundamental concepts:

White light is a combination of light waves of different wavelengths, from dark red to dark violet or photons of different energies, the spectrum of sunlight, known to Newton.

The second is that the color of the sky is caused by the selective scattering of waves or photons with a certain wavelength.

Third– light is scattered SELECTIVELY, that is, DIFFERENTLY for all parts of the spectrum, only on particles whose size is much smaller than the wavelength of any color. And this scattering occurs according to Rayleigh’s law, inversely proportional to the length of the light wave: The longest light wave is of a dark red color. the lower limit of vision of our vision is 7400 Angstroms (an Angstrom is one hundred millionth of a centimeter) and up to dark violet – the upper limit of our vision is 3800 A.

That is, the waves differ in length by about two times. In accordance with Rayleigh’s law, dark violet, short-wave light is scattered on small particles to the fourth degree more than red, that is, about 16 times (two to the fourth degree).

On particles close and large in size to the wavelengths, the entire spectrum is scattered evenly and we see white light again.

It is also necessary to take into account the degree of representation of each color in the spectrum. The sun is a yellow dwarf, because the maximum of its visible radiation lies in the yellow part of the spectrum.

Tyndall’s idea.

What speaks for her?

Tyndall himself chemically obtained a mixture of very small and homogeneous particles from hydrochloric acid and nitroisobutane vapors, which glowed blue in diffused light, surpassing the blue of the Italian sky in brightness. Tyndall thought that the fine dust in the atmosphere gave this blueness.

What does he say against it?

Yes, there are indeed particles in natural dust, so small that, as in Tyndall’s experiments, they could scatter mainly only blue-blue light. But as a percentage of the total mass of dust constantly hanging in the air, there are very few of them. Most of the particles have sizes from a few microns or less, but not much.

(In order to be permanently suspended in the air due to the continuous Brownian motion, the particles must be no larger than a few microns. (A micron is one ten thousandth of a centimeter! And, I repeat, Angstrom is one hundred millionth!)

The second “against” is the different dustiness of the atmosphere over cities and rural areas.

Above the cities, the dustiness is many times greater and, if Tyndall’s idea were correct, it would be above the cities that the sky would glow with a clear and bright blue. In fact, it’s just the opposite. The sky over the cities on a sunny day is slightly whitish, due to dust, but not bright and pure blue.

The third “against” is that if we consider the atmosphere illuminated by sunlight “in the context”, from a high–flying airplane or satellite, then, since the air is more dusty the closer it is to the surface of the Earth, then the maximum blueness should just be at the bottom, at the surface. The images also show a whitish layer near the earth’s surface, and the blueness increases just from a multi-kilometer height, gradually turning into the blackness of outer space.

Fourth, in the case of selective scattering of light on dust particles, a dust storm should generate a bright blue glow, which has never been observed in practice, as well as a bright blue fog!

(The colored fog is present only in the imagination of poets excited by decent doses of alcohol:

“And again in the golden mist

It’s like an unearthly chord”

And the Block, the Aviator

“The siliceous path glitters through the fog”

“The earth sleeps in a blue mist”

M.Lermontov. I go out alone on the road

“Floating in a lilac fog

Dead dumb Ships”

A. Vertinsky)

Fifth, red sunrises and sunsets are conventionally explained by the fact that, de, the light of the Sun spreads near the earth’s surface and passes to us through thick layers of a dusty atmosphere, which produces a “selection” of wavelengths. Red rays, the longest-wavelength ones, scatter in a dusty atmosphere many times less than blue ones, which is why sunrises and sunsets turn red.

But then the dust should be denied all the previous “disadvantages”, which, nevertheless, are present!

Since dust scatters rays according to Rayleigh’s law, then all the above facts and considerations should be rejected and, contrary to theory and practice, dust should be recognized as the creator of both blue and red skies!

For one of two things, if dust scatters rays in different ways, then it must create a blue color, not just red, or it CANNOT produce selective scattering by wavelengths at all!

Rayleigh’s idea.

What speaks for her?

The first is that the molecules of air, the main gases of its constituents nitrogen and oxygen, are several Angstroms in size, well suited for scattering light according to Rayleigh’s law! They are really very small compared to the wavelength of light. That’s why they scatter blue light much better than red.

What’s against it?

Mandelstam theoretically proved that air molecules at normal density, pressure and temperature are located so tightly to each other that THEY CANNOT be individual scatterers of light waves. By this alone, Rayleigh’s whole idea became wrong.

Mandelstam’s idea.

What speaks for her?

According to his idea, light is scattered NOT ON INDIVIDUAL MOLECULES (see above – why), but on their chaotically arising clusters-discharges, that is, on fluctuations in air density. The higher the density, the more fluctuations per unit volume. These instantaneously arising and disappearing “compression-discharge” themselves are also very small in size and therefore can scatter light according to Rayleigh’s law.

What’s against it?

First, for intense scattering of light waves, a strong difference in the “optical densities” of these fluctuations is necessary. If these are dust particles, then light waves could be strongly scattered on them. If we talk about individual molecules flying in the void, then each one can also be an individual scattering center. And, here are the spontaneously occurring point fluctuations in air density, which can HARDLY differ MUCH in density from the average density of the surrounding air.

The second is related to the first. Since this process is random, probabilistic, the more molecules must collide in a given small volume in order to create a significantly changed air density, the less likely such an event is. And the fewer molecules there should be in a given volume at a given moment, the more likely this coincidence is. It follows from this reasoning that for strong fluctuations in density in a small volume, at a given moment there must be MANY molecules purely by chance, which contradicts the laws of probability.

Either there are many molecules, but there will be too few such fluctuations to scatter a large number of light waves, or there are few molecules, but much in large quantities, but then, due to the small difference in the density of the fluctuation from the average optical density of the surrounding air, the scattering will be extremely weak in intensity.

Third, again, we look at the “section of the atmosphere”. If Mandelstam’s idea were correct, then the atmosphere would glow with a bright blue light precisely near the surface of the Earth (there is more air density there – there are more fluctuations …) But again, the adjacent multi-kilometer layer of air has a distinctly whitish, and not a blue shade! And only somewhere high up, bright blue suddenly appears.

Resume.

First, we have to discard Tyndall’s idea of dust, because it mostly consists of particles equal to and much larger than the wavelengths of light, and it can only add a certain whitishness to the color of the sky, which is observed in practice.

Secondly, Ray’s idea is CORRECT, and it explains well the blue color of the UPPER LAYERS of the ATMOSPHERE, which create this blue scattering. The fact is that with altitude, the density of the atmosphere decreases, that is, air molecules THIN OUT, and flying in relative emptiness CAN BE strong individual wave scatterers according to Rayleigh’s law!

But only at high altitude.

This EXPLANATION is supported by such a well-known fact: From the ground, we can see a high-flying plane AGAINST the blue sky. If the entire atmosphere glowed blue, and the closer to the surface, the stronger, we simply could not see something flying at an altitude of 12-16 km, and 90% of the entire mass of the atmosphere is concentrated in the Troposphere (a layer 16 km thick)!

Mandelstam’s idea is also TRUE, but it just explains not the blueness of the sky, but its redness at dawn and sunset.!

At the same time, the Sun’s light passes through thick layers of DENSE air, where there are many fluctuations, but due to the small difference in their optical density compared to the average in dense air, the intensity of the light scattered by them is very small and only very thick layers of such fluctuations can really give a noticeable effect of wave selection by their lengths. Therefore, red waves pass through thick layers of fluctuations, while blue ones are weakly scattered. The “cross-sectional” images of the atmosphere show a slight blue tint of the part of the atmosphere at the edge of the Earth’s disk. This is the weak scattering of Mandelstam. Looking vertically, we see a layer of air only a few tens, not hundreds and thousands of kilometers, and there the main role in the blueness is played by the upper layer of rarefied air, individual molecules scattering light according to Rayleigh’s law.

22 VI 2024

P.S. I forgot to add that the light scattered by the molecules of discharged air is polarized, that is, the directions of the vectors of its electric and magnetic induction occupy a position in space that is quite definite for all waves or photons. Everyone can easily see this if they look at the blue sky through a polarizer, which can be selected from any children’s toy with a screen made of liquid crystals, the top layer of transparent plastic. By rotating such a piece around an axis perpendicular to its plane, the interested person will notice strong changes in the brightness of the sky from blue to dark blue.

What causes this polarization of scattered light?

The effect of geoelectric and geomagnetic fields on molecules. Because a molecule is not something frozen for centuries, but a fully actively functioning mechanism in which atoms are connected to each other by common exchange electrons of the outer shells. So they are not dipoles or quadrupoles, but tripoli. Where there are positive ions at the edges and negative pulsating charges in the middle. Naturally, such molecules have their own electric and magnetic fields, which are quite complex in shape, and therefore these geofields can rotate them, positioning all the molecules in a separate way, with a certain orientation in space, which means that the radiation scattered by such molecules also has an ordered polarized character.