We are all used to the color of the sky - characteristicnon-permanent. Fog, clouds, time of day - all affect the color of the dome overhead. Her daily change does not occupy the minds of most adults, which is not the case with children. They are constantly interested in why the sky is blue from the point of view of physics or what colors sunset to red. Let's try to understand these not the most simple questions.
Changeable
You should start by answering the question that,in fact, the sky represents. In the ancient world, it was really seen as a dome covering the Earth. Today, however, hardly anyone knows that, no matter how high a curious explorer may ascend, he will not be able to reach this dome. The sky is not a thing, but rather a panorama that opens when viewed from the surface of the planet, a kind of visibility woven from light. And if you watch from different points, it may look different. So, from the window of an airplane that has risen above the clouds, a completely different view opens up than from the ground at this time.
The clear sky is blue, but it is worth running across the clouds -and it becomes gray, lead or off-white. The night sky is black, sometimes reddish patches can be seen on it. This is a reflection of the artificial lighting of the city. The cause of all such changes is light and its interaction with air and particles of various substances in it.
Nature color
To answer the question of whythe sky is blue in terms of physics, you need to remember what color is. This is a wave of a certain length. Light coming from the Sun to the Earth is seen as white. Even with the experiments of Newton it is known that white light is a beam of seven rays: red, orange, yellow, green, blue, blue and violet. Colors differ in wavelength. The red-orange spectrum includes the most impressive waves in this parameter. The colors of the blue-green part of the spectrum are characterized by a short wavelength. The decomposition of light into the spectrum occurs when it collides with molecules of various substances, with some of the waves can be absorbed, and some - scattered.
Investigation of the cause
Многие ученые пытались объяснить, почему небо blue in terms of physics. All researchers sought to detect a phenomenon or process that scatters light in the atmosphere of the planet in such a way that as a result only the blue reaches us. The first candidates for the role of such particles were molecules of ozone and water. It was believed that they absorb the red light and let the blue light through, and as a result we see the sky in blue. The calculations that followed, however, showed that the amount of ozone, ice crystals and water vapor molecules that is in the atmosphere is not enough to give the sky a blue color.
Cause of pollution
На следующем этапе исследований Джоном Тиндаллом it has been suggested that dust plays the role of the desired particles. Blue light has the greatest resistance to dispersion, and therefore is able to pass through all layers of dust and other suspended particles. Tyndall conducted an experiment that confirmed his assumption. In the laboratory, he created a model of smog and illuminated it with bright white light. Smog has acquired a blue tint. The scientist made an unequivocal conclusion from his research: the color of the sky is determined by particles of dust, that is, if the air of the Earth was clear, then the blue skies shone above people's heads.
Lord research
The final point in the question of why the skyblue (from the point of view of physics), put the English scientist, Lord D. Rayleigh. He proved that it wasn’t dust or smog that paints the space above our head in the shade we’ve seen. The thing is in the air. Gas molecules absorb most of the light and most of all the longest waves, equivalent to red. Blue dissipates. That’s what explains today the color of the sky in clear weather.
Attentive will notice that, following the logic of scientists,the dome above the head should be purple, since it is this color that has the shortest wavelength in the visible range. However, this is not a mistake: the proportion of violet in the spectrum is much less than blue, and even human eyes are more sensitive to the latter. In fact, the blue we see is the result of mixing blue with violet and some other colors.
Sunsets and clouds
Everyone knows that at different times of the day you can seedifferent color of the sky. Photos of beautiful sunsets over the sea or lake are a great illustration of this. All sorts of shades of red and yellow in combination with blue and dark blue make this spectacle unforgettable. And it is explained by the same scattering of light. The fact is that during dusk and dawn, the sun's rays have to overcome a much larger path through the atmosphere than at the height of the day. At the same time, the light of the blue-green part of the spectrum is scattered in different directions and the clouds located on the horizon line become colored in shades of red.
When the sky is clouded, the picturecompletely changing. The sun's rays can not overcome the dense layer, and most of them simply do not reach the ground. Rays that have managed to pass through the clouds, meet with water drops of rain and clouds, which again distort the light. As a result of all these transformations, white light reaches the earth, if the clouds are small in size, and gray, when the sky is covered with impressive clouds, which again absorb part of the rays.
Other heavens
It is interesting that on other planets of the Solarsystem when viewed from the surface you can see the sky, very different from the earth. On cosmic objects deprived of the atmosphere, the sun's rays freely reach the surface. As a result, the sky is black here, without any hue. Such a picture can be seen on the Moon, Mercury and Pluto.
The Martian sky has a red-orange hue.The reason for this lies in the dust, which is saturated with the atmosphere of the planet. It is painted in different shades of red and orange. When the sun rises above the horizon, the Martian sky becomes pinkish-red, while its portion immediately surrounding the disk of the star appears blue or even purple.
The sky above Saturn is the same color as on Earth. Aquamarine skies extend over Uranus. The reason lies in the methane haze located in the upper layers of the planet’s atmosphere.
Venus from the eyes of researchers hides tightcloud layer. It does not allow the rays of the blue-green spectrum to reach the surface of the planet, therefore the sky here is yellow-orange with a gray strip along the horizon.
Study of daytime space above your headreveals no less miracles than exploring the starry sky. Understanding the processes occurring in the clouds and behind them helps to comprehend the reason for the things that are quite usual for the average person, which, however, cannot be explained on the fly by far everyone.
