Atmosphere

(See also: Extraterrestrial atmospheres and Extraterrestrial skies) The exosphere (Ancient Greek: ἔξω éxō "outside, external, beyond", Ancient Greek: σφαῖρα sphaĩra "sphere") is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the density is too low for them to behave as a gas by colliding with each other.

The mesosphere (/ˈmɛsoʊsfɪər/; from Greek mesos "middle" and sphaira "balls") is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the mesopause.

The mesopause is the temperature minimum at the boundary between the mesosphere and the thermosphere atmospheric regions.

The stratosphere (/ˈstrætəˌsfɪər, -toʊ-/) is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere.

Sunset or sundown, is the daily disappearance of the Sun below the western horizon as a result of Earth's rotation.

The planetary boundary layer (PBL), also known as the atmospheric boundary layer (ABL), is the lowest part of the atmosphere, extending from the ground to the bottom of where cumulus clouds form.

Sunrise or sun up is the instant at which the upper edge of the Sun appears over the eastern horizon in the morning.

The atmosphere of Mars is the layer of gases surrounding Mars.

The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere.

The troposphere is the lowest portion of Earth's atmosphere, and is also where all weather takes place.

The International Standard Atmosphere (ISA) is an atmospheric model of how the pressure, temperature, density, and viscosity of the Earth's atmosphere change over a wide range of altitudes or elevations.

Atmospheric pressure, sometimes also called barometric pressure, is the pressure exerted by the weight of air in the atmosphere of Earth (or that of another planet).

Thunder is the sound caused by lightning.

The sky (or celestial dome) is everything that lies above the surface of the Earth, including the atmosphere and outer space.

Ozone (O3) is a constituent of the troposphere (it is also an important constituent of some regions of the stratosphere commonly known as the ozone layer).

Atmospheric diffraction is manifested in the following principal ways: * Optical atmospheric diffraction * Radio wave diffraction is the scattering of radio frequency or lower frequencies from the Earth's ionosphere, resulting in the ability to achieve greater distance radio broadcasting.

Atmospheric methane is the methane present in Earth's atmosphere.

A runaway greenhouse effect is a process in which a net positive feedback between surface temperature and atmospheric opacity increases the strength of the greenhouse effect on a planet until its oceans boil away.

The barometric formula, sometimes called the exponential atmosphere or isothermal atmosphere, is a formula used to model how the pressure (or density) of the air changes with altitude.