The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).
Atmospheric stratification describes the structure of the atmosphere, dividing it into distinct layers, each with specific characteristics such as temperature or composition. The atmosphere has a mass of about 5×1018 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. An altitude of 120 km (75 mi) is where atmospheric effects become noticeable during atmospheric reentry of spacecraft. The Kármán line, at 100 km (62 mi), also is often regarded as the boundary between atmosphere and outer space.
Air is the name given to the atmosphere used in breathing and photosynthesis. Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%. While air content and atmospheric pressure vary at different layers, air suitable for the survival of terrestrial plants and terrestrial animals is currently only known to be found in Earth's troposphere and artificial atmospheres.
Read more about Atmosphere Of Earth: Composition, Optical Properties, Circulation
Famous quotes containing the words atmosphere of, atmosphere and/or earth:
“The atmosphere of orthodoxy is always damaging to prose, and above all it is completely ruinous to the novel, the most anarchical of all forms of literature.”
—George Orwell (1903–1950)
“The base of all artistic genius is the power of conceiving humanity in a new, striking, rejoicing way, of putting a happy world of its own creation in place of the meaner world of common days, of generating around itself an atmosphere with a novel power of refraction, selecting, transforming, recombining the images it transmits, according to the choice of the imaginative intellect. In exercising this power, painting and poetry have a choice of subject almost unlimited.”
—Walter Pater (1839–1894)
“My darling girl, Unfortunately this earth is not ... a fairy- land, but a struggle for life, perfectly natural and therefore extremely harsh. All the same, or precisely for this reason, it is happiness and comfort for us men to have a precious sweetheart—and I have the most precious, the dearest and best of all!”
—Martin Bormann (1900–1945)