"By mole fraction (i.e., by number of molecules), dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases."
Study of the composition, structure, and dynamics of planetary atmospheres, including clouds, winds, and temperature variations.
Spectroscopy: The study of how light interacts with matter, particularly gases in a planetary atmosphere. This includes the absorption, emission, and scattering of light.
Radiative transfer: The process by which electromagnetic radiation moves through a medium, such as a planetary atmosphere. It involves absorption, emission, and scattering of radiation by molecules and particles.
Atmospheric composition: The study of the gases and particles that make up a planetary atmosphere. This includes the chemistry of these components, their abundance, distribution, and the effects they have on climate and weather.
Cloud properties: The study of the physical and chemical characteristics of clouds in planetary atmospheres. This includes their formation, composition, structure, and dynamics.
Atmospheric dynamics: The study of the movements and circulation patterns of gases in a planetary atmosphere. This includes the interactions between winds, temperature, and pressure, as well as atmospheric waves and turbulence.
Remote sensing techniques: The use of imaging and spectroscopic instruments to study planetary atmospheres from a distance. This includes techniques such as spectroscopy, radiometry, and imaging.
Planetary climate: The study of how the atmosphere of a planet affects its climate and weather patterns. This includes the effects of greenhouse gases, atmospheric circulation, and surface temperature.
Planetary evolution: The study of how planetary atmospheres have changed over time. This includes the role of geological and biological processes in shaping the composition and dynamics of planetary atmospheres.
Planetary exploration: The use of spacecraft to study planetary atmospheres up close. This includes missions to the planets and moons of our solar system, as well as the study of exoplanet atmospheres.
Data analysis: The techniques used to analyze and interpret data collected from remote sensing instruments, spacecraft, and other sources. This includes statistical methods, modeling, and visualization.
Terrestrial Atmospheres: These include our own planet Earth as well as other rocky planets in our solar system such as Mars, Venus, and Mercury. Terrestrial atmospheres are composed primarily of nitrogen, oxygen, and small amounts of other gases.
Gas Giants Atmospheres: These are the planets Jupiter, Saturn, Uranus, and Neptune. These planets have very thick atmospheres made up primarily of hydrogen and helium.
Ice Giant Atmospheres: These are the planets Uranus and Neptune. These planets have an atmosphere that is primarily composed of hydrogen and helium, but with much higher amounts of more complex molecules, such as methane, which gives them a blueish color.
Exoplanet Atmospheres: These are the atmospheres of planets in other star systems. Remote sensing observations of exoplanet atmospheres provide insight into their composition, temperature, and other properties.
Titan Atmosphere: Titan is the only moon in our solar system that has a substantial atmosphere. The atmosphere is primarily composed of nitrogen, with small amounts of methane and other gases.
Comet Atmospheres: When a comet gets close to the sun, it heats up and releases gas and dust from its surface. These gases form a coma around the comet that can be studied with remote sensing.
Asteroid Atmospheres: Some asteroids have very thin atmospheres, called exospheres, that can be studied with remote sensing.
Lunar Atmosphere: The moon has a very tenuous atmosphere composed of trace amounts of gases, such as helium and argon.
Martian Atmosphere: The Martian atmosphere is mainly composed of carbon dioxide with nitrogen and argon present as well. There are also trace amounts of other gases, such as methane and water vapor.
Venusian Atmosphere: The Venusian atmosphere is composed primarily of carbon dioxide, with small amounts of nitrogen and sulfuric acid. The thick atmosphere causes a greenhouse effect, making Venus the hottest planet in the solar system.
"The atmosphere of Earth creates pressure, absorbs most meteoroids and ultraviolet solar radiation, warms the surface through heat retention (greenhouse effect), allowing life and liquid water to exist on the Earth's surface, and reduces temperature extremes between day and night."
"Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere."
"Air composition, temperature, and atmospheric pressure vary with altitude."
"Within the atmosphere, air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is found only in Earth's troposphere."
"The atmosphere changed significantly over time, affected by many factors such as volcanism, life, and weathering."
"Recently, human activity has also contributed to atmospheric changes, such as global warming, ozone depletion and acid deposition."
"The atmosphere has a mass of about 5.15×10^18 kg."
"Three quarters of the atmosphere's mass is within about 11 km (6.8 mi; 36,000 ft) of the surface."
"The atmosphere becomes thinner with increasing altitude, with no definite boundary between the atmosphere and outer space."
"The Kármán line, at 100 km (62 mi) or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space."
"Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi)."
"Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition."
"The study of Earth's atmosphere and its processes is called atmospheric science (aerology)."
"Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann."
"Atmospheric science includes multiple subfields, such as climatology and atmospheric physics."
"The study of historic atmosphere is called paleoclimatology."
"The atmosphere [...] reduces temperature extremes between day and night (the diurnal temperature variation)."
"The atmosphere of Earth creates [...] absorbs most meteoroids and ultraviolet solar radiation."
"The atmosphere of Earth creates [...] allowing life and liquid water to exist on the Earth's surface."