Know Our ‘ATMOSPHERE’
The permanent gases whose percentage does not change from day to day are nitrogen, oxygen, and argon. Nitrogen accounts for 78% of the atmosphere, oxygen 21%, and argon 0.9%. Gases like carbon dioxide, methane, and ozone are trace gases that account for about a tenth of one percent of the atmosphere.
Pictorial Presentation of the percentage of gases in our Earth’s Atmosphere
More details of The Atmosphere:
An atmosphere (from Ancient Greek ἀτμός (atmos), meaning ‘vapour’, and σφαῖρα (sphaira), meaning ‘ball’ or ‘sphere’) is a layer or a set of layers of gases surrounding a planet or other material body, that is held in place by the gravity of that body. An atmosphere is more likely to be retained if the gravity it is subject to is high and the temperature of the atmosphere is low.
The atmosphere of Earth is composed of nitrogen (about 78%), oxygen (about 21%), argon (about 0.9%), carbon dioxide (0.04%) and other gases in trace amounts. Oxygen is used by most organisms for respiration; nitrogen is fixed by bacteria and lightning to produce ammonia used in the construction of nucleotides and amino acids; and carbon dioxide is used by plants, algae, and cyanobacteria for photosynthesis. Helps to protect living organisms from genetic damage by solar ultraviolet radiation, solar wind and cosmic rays. The current composition of the Earth’s atmosphere is the product of billions of years of biochemical modification of the paleoatmosphere by living organisms.
The term stellar describes the outer region of a star and typically includes the portion above the opaque photosphere. Stars with sufficiently low temperatures may have outer atmospheres with compound molecules.
Composition Of Gases in the Atmosphere:
A planet’s initial atmospheric composition is related to the chemistry and temperature of the local solar nebula during planetary formation and the subsequent escape of interior gases. The original atmospheres started with a rotating disc of gases that collapsed to form a series of spaced rings that condensed to form the planets. The planet’s atmospheres were then modified over time by various complex factors, resulting in quite different outcomes.
The composition of Earth’s atmosphere is largely governed by the by-products of the life that it sustains. Dry air from Earth’s atmosphere contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and traces of hydrogen, helium, and other “noble” gases (by volume), but generally a variable amount of water vapor is also present, on average about 1% at sea level.
The low temperatures and higher gravity of the Solar System’s giant planets—Jupiter, Saturn, Uranus, and Neptune—allow them more readily to retain gases with low molecular masses. These planets have hydrogen–helium atmospheres, with trace amounts of more complex compounds.
Two satellites of the outer planets possess significant atmospheres. Titan, a moon of Saturn, and Triton, a moon of Neptune, have atmospheres mainly of nitrogen. When in the part of its orbit closest to the Sun, Pluto has an atmosphere of nitrogen and methane similar to Triton’s, but these gases are frozen when it is farther from the Sun.
Other bodies within the Solar System have extremely thin atmospheres, not in equilibrium. These include the Moon (sodium gas), Mercury (sodium gas), Europa (oxygen), Io (sulfur), and Enceladus (water vapor).
The first exoplanet whose atmospheric composition was determined is HD 209458b, a gas giant with a close orbit around a star in the constellation Pegasus. Its atmosphere is heated to temperatures over 1,000 K and is steadily escaping into space. Hydrogen, oxygen, carbon, and sulfur have been detected in the planet’s inflated atmosphere.
Above details courtesy: Wikipedia