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
The most common gas people breathe from clean air is nitrogen. Air is a mixture of gases, and the air on Earth contains about 78 percent nitrogen and about 21 percent oxygen. Argon, carbon dioxide neon, helium, methane, krypton, hydrogen and xenon are in much smaller amounts.Full Answer >
The ozone layer, which is part of the stratosphere, is comprised of the major atmospheric gases nitrogen, oxygen and argon, but also contains a significantly higher concentration of the trace gas ozone than the other layers of the atmosphere. The other trace gases include carbon dioxide, neon, helium, methane and the manmade chlorofluorocarbons, or CFCs. The CFCs reaching the stratosphere from the Earth's surface have become a cause for global concern because of the role they play in the chemical reaction that removes ozone from the atmosphere.Full Answer >
The air that makes up Earth's atmosphere contains 20.9 percent oxygen. This is true up to about 70,000 feet above sea level. However, above 10,000 feet, the atmosphere becomes too thin to support human life, even though its proportions do not change much.Full Answer >
Nitrogen and oxygen are the two main gases in the air that people breathe. Air is in the lowest 6.2 miles of the atmosphere and is made of 78 percent nitrogen, 21 percent oxygen and 1 percent trace gases and aerosols.Full Answer >