What is Atmosphere ?Define it's Layer
The Atmosphere is an insulating blanket protecting the Earth. It softens the intense light and heat of the Sun . It's Ozonic layer absorbs most of the very deleterious ultraviolet rays from sun and thus protects living organisms from extinction.
The Atmosphere is bound to the Earth by gravity. Satellite like the moon , which have very low gravitational power, cannot and do not hold an atmosphere.
air pressure simply means the weight of the entire air volume column over a given point near of has very little bit a letter of their weight around 1.6 gram at the sea level the air pressure is 3.6 gram per square centimetre this pressure is usually described as one atmosphere .
The atmosphere is composed of various gases and water vapour, and in its uppermost reaches, it is charged with subatomic particles. Up to about 50km from the Earth, the Atmosphere consists of about 78% nitrogen, 21% oxygen and miner percentage of argon, carbon dioxide, neon, helium and methane in that order. Above 50km, the Atmosphere is made up of atomic oxygen, ozone, helium and hydrogen. The presence of atomic is the upper Atmosphere has recently been confirmed by a camera left on the surface of the moon by the Apollo-16 mission. The camera has revealed a cloud of atomic hydrogen extending outwards from the Earth to about 64,000 km.
Water vapour is present in the lower Atmosphere, say up to 12 km, in concentration ranging from 0.01% to 1%. Although the amount of water vapours in the Atmosphere is very small, it's importance is very great, for without water in the Atmosphere, there would be no water on Earth. Water enters the Atmosphere by evaporation from the hydrosphere (and by transpiration) and leaves the Atmosphere by precipitation as snow or rain. It is a never ending 2-way traffic.
Clouds are made of water vapour that has Evaporated from the earth. They are very tiny droplets of microscopic size and are too light to fall down as rain . So they ride on the airwaves until the contents and then fall down as rain it is the Surge of electricity from the earth that makes lightning the awesome phenomenon that it is the lead, however is taken by the clouds which send down a rather weak stroke called the leaderstroke. The earth responds by sending up a much more massive stroke to the clouds. The whole thing takes less than a second so that we see the leader stroke and the counter stroke as one flash of lightning .
Dry air is highly resistant to Electricity when the air is loaded with water vapour it becomes a better conductor nevertheless much power is required for the stroke to rip through the air this excessive discharge of electricity heats up the air around the passage of the stroke to incandescent temperatures, 10,000°celsius. It is this glowing air that we see as lightning flash. The heat also causes of sudden expansion of Air which as the heat appears contracts quickly again this sudden expansion and contraction produce the familiar thunder clap. Although occur at the same time we see the flash first for light travels faster than sound.
The character and composition of the Atmosphere changes as we go higher and higher . Altitudinally arranged, there are 4 important spheres, with 3 pause they are:
- Troposphere with Tropopause.
- Stratosphere with Stratosphere.
- Mesosphere with Mesopause.
- Ionosphere .
- Exosphere.
Troposphere
The one nearest the earth between 8 and 12 km is called proposed here here the temperature decrease with increase in height it's the densest that contains water vapour and dust clouds are found here since 80% of the air mass is concentrated here it is capable of influencing Earth's climate. Tropopause is what separates Troposphere from Stratosphere.
Stratosphere.
Stratosphere extends from 12 to 30 km and the temperature remains study it is free from water vapour, cloud and dust Jets often fly in this zone. Ozone protects the earth from the bad effects of the UV rays radiating from the sun stratosphere divide stratosphere from mesosphere.
Mesosphere
Mesosphere extends up to 80 km and is very cold Still higher, starting about 80 km above the surface is the ionosphere in this uppermost region many of the molecules and atoms of the earth's atmosphere are ionized (carry either a positive or negative electric charge.)
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