Atmosphere

The atmosphere is a layer of gases that surrounds a planet, including Earth, and is held in place by gravity. On Earth, the atmosphere extends approximately 10,000 kilometers (6,200 miles) from the surface, although most of its mass is concentrated within the first 50 kilometers (31 miles). It plays a crucial role in supporting life by providing oxygen for respiration, regulating temperature, and protecting living organisms from harmful solar and cosmic radiation.

Earth's atmosphere is composed primarily of nitrogen (about 78%) and oxygen (about 21%), with trace amounts of argon, carbon dioxide, neon, helium, methane, and other gases. Its structure is divided into several layers based on temperature gradients: the troposphere, where weather occurs; the stratosphere, which contains the ozone layer; the mesosphere; the thermosphere; and the exosphere, the outermost layer where atoms and molecules escape into space.

The atmosphere influences various environmental processes, including climate, weather patterns, and the water cycle. It also acts as a thermal blanket, trapping heat through greenhouse gases and maintaining the planet's habitable temperature range. Human activities, particularly fossil fuel combustion and deforestation, have impacted atmospheric composition by increasing greenhouse gases, leading to global warming and climate change.

Studying the atmosphere is critical for understanding Earth's environmental systems and addressing challenges related to climate change and air pollution. Atmospheric science integrates disciplines such as meteorology, climatology, and environmental science to analyze atmospheric processes and predict weather, climate variability, and long-term trends. Protecting the atmosphere's integrity is essential for sustaining life and ensuring environmental stability.