Knowra Atmosphere of Earth Atmosphere of Earth The atmosphere of Earth is the layer of gases surrounding the planet, held by gravity. Its temperature and composition vary with altitude, forming distinct regions.
Troposphere : The lowest atmospheric layer, where most weather and clouds occur. Nearly all familiar weather takes place in this lowest layer.
Atmospheric pressure : The force per unit area exerted by the weight and motion of atmospheric gases. The weight of overlying air makes pressure decrease with altitude.
Weather : The state of the atmosphere at a place and time, including temperature, wind, clouds, and precipitation. Weather is the short-term behavior of the lower atmosphere.
Atmospheric evolution : The long-term change in a planet’s atmospheric composition and structure through physical, chemical, and biological processes. Earth’s present atmosphere emerged through successive changes in gases and sources.
Atmosphere of Venus : A dense atmosphere composed chiefly of carbon dioxide, with crushing surface pressure and extreme greenhouse heating. Venus illustrates how a carbon-dioxide-rich atmosphere differs from Earth’s nitrogen-oxygen air.
Stratosphere : The atmospheric layer above the troposphere, containing the ozone layer and warming with altitude. Ozone absorption creates this layer’s distinctive temperature increase with height.
Hydrostatic equilibrium : A balance in which pressure gradients support a fluid against gravity. This balance explains the atmosphere’s vertical pressure structure.
Climate : Long-term patterns and statistics of weather in a region or across the planet. Climate describes persistent atmospheric conditions and their variability.
Volcanic outgassing : The release of gases from a planet’s interior through volcanic and related processes. Outgassing supplied much of the water vapor, carbon dioxide, and nitrogen in early air.
Atmosphere of Mars : A thin atmosphere composed mostly of carbon dioxide, with low surface pressure and large temperature variations. Mars shows how weaker gravity and limited atmospheric replenishment can yield a thin envelope.
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