An atmosphere (New Latin atmosphaera, created in the 17th century from Greek ἀτμός "vapor" and σφαῖρα "sphere") is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low. Some planets consist mainly of various gases, but only their outer layer is their atmosphere.
The term stellar atmosphere describes the outer region of a star, and typically includes the portion starting from the opaque photosphere outwards. Relatively low-temperature stars may form compound molecules in their outer atmosphere. Earth's atmosphere, which contains oxygen used by most organisms for respiration and carbon dioxide used by plants, algae and cyanobacteria for photosynthesis, also protects living organisms from genetic damage by solar ultraviolet radiation. Its current composition is the product of billions of years of biochemical modification of the paleoatmosphere by living organisms.
Read more about Atmosphere: Pressure, Escape, Composition, Circulation, Importance
Famous quotes containing the word atmosphere:
“The man who, from the beginning of his life, has been bathed at length in the soft atmosphere of a woman, in the smell of her hands, of her bosom, of her knees, of her hair, of her supple and floating clothes, ... has contracted from this contact a tender skin and a distinct accent, a kind of androgyny without which the harshest and most masculine genius remains, as far as perfection in art is concerned, an incomplete being.”
—Charles Baudelaire (1821–1867)
“I have wrestled with death. It is the most unexciting contest you can imagine. It takes place in an impalpable greyness, with nothing underfoot, with nothing around, without spectators, without clamor, without glory, without the great desire of victory, without the great desire of defeat, in a sickly atmosphere of tepid skepticism, without much belief in your own right, and still less in that of your adversary.”
—Joseph Conrad (1857–1924)
“The atmosphere parents wish to create when talking with children about birth and reproduction is warm, honest, and reassuring, one that tells children they are free to ask questions as often as they need to, and you will answer them as lovingly as you know how.”
—Joanna Cole (20th century)