Atmosphähre

The Atmosphähre is the gaseous shell that envelops a planet, retained by gravity and interacting with radiation from the sun, the surface, and living systems. On Earth, it extends from the surface to the edge of space and determines climate, weather, and habitability.

Composition and layers: The atmosphere is composed mainly of nitrogen (about 78%) and oxygen (about 21%), with argon, carbon dioxide, neon, helium, methane, water vapor, and other trace gases. Temperature changes with altitude, leading to distinct layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The troposphere contains most water vapor and weather; the stratosphere houses the ozone layer, which absorbs UV radiation; the thermosphere contains the ionosphere at high altitudes.

Climate and weather: The atmosphere mediates heat and light, supporting weather systems. Solar energy drives convection, cloud formation, and winds. The greenhouse effect, caused by water vapor, CO2, methane, and other gases, keeps surface temperatures in a range that sustains life.

Function and protection: It shields living organisms from harmful space radiation and meteoroids; the ozone layer protects from UV; precipitation cycles; climate regulation; supports biosphere by providing oxygen and a medium for chemical cycles.

Human interaction and study: Anthropogenic emissions alter the composition, reinforcing the greenhouse effect and contributing to climate change. Atmospheric scientists monitor the thickness of layers, gas concentrations, aerosols, and radiation balance with ground-based stations, weather balloons, and satellites.

In culture and technology: The atmosphere is essential for aviation, space travel, and satellite operations; understanding it helps in weather forecasting, climate research, and environmental policy.