There are many proximate causes for changes to the color of the sky, but they all involve the way light is diffracted through the air. Light from the sun can be bent as it moves through the Earth's atmosphere, and the wavelengths of light that are able to pass most easily through the air give the sky its color.Know More
Light from the sun is white. White light is composed of all of the colors visible to humans. As this light passes through the oxygen-rich atmosphere around the Earth, the short wavelengths of light that correspond to the colors violet and indigo are filtered out, and their wavelengths spread across the sky. At sunrise and sunset, when the sun is close to the local horizon, light must pass through more air before reaching the observer. This spreads light out more than usual, leaving primarily the longer wavelengths of yellow, orange and red to be seen.
Particles in the air can create a similar effect. Sometimes a volcanic eruption, industrial pollution or forest fire delivers large quantities of ash and dust to the upper atmosphere. This tends to darken the surface and scatter light in ways that turn the sky different colors.Learn more in Atmosphere
The sky is blue as a result of Rayleigh scattering. Rayleigh scattering represents the high frequency of gas molecules hitting and absorbing blue light. As the horizon turns pale, the blue light has to pass through more air to reach the human eye, which causes the horizon to appear white.Full Answer >
The sky is a common term for Earth's atmosphere, which is approximately 60 miles thick, according to NASA. The atmosphere is composed of different levels, with the exosphere marking the boundary of space. According to University at Albany, the exosphere observable from space extends 60,000 miles minimum from Earth's surface.Full Answer >
The southern lights, or the "aurora australis," are diffuse sheets of lights in the sky of the southern hemisphere. The aurora australis are the southern hemisphere’s counterpart to the northern lights, or aurora borealis, in the northern hemisphere.Full Answer >
Pure air is a homogeneous mixture made primarily of nitrogen and oxygen. Its elements are not readily separated or distinguished from one another. The composition of air is not uniform and may be influenced by environmental factors, such as industrial pollution, heavy forestation or volcanic activity.Full Answer >