Definition of the Atmosphere:
The vast expanse of air which envelopes the earth
all round is called the Atmosphere.
The atmosphere is a
thin layer of gas held to the earth by gravitational attraction – F.J.Monkhouse
The atmosphere is a
deep blanket of gases which entirely envelopes the earth – H.J.Critchfield
The Air of the
Atmosphere:It is
colourless, odourless and tasteless. We
cannot feel the presence of the air unless it blows as wind. We cannot feel the presence of the air unless
it blows as wind.
The thickness of the
Atmosphere: Previously, the scientists thought that the
thickness of the atmosphere was just 800km. around the Earth. But, now, the latest discoveries hint at the
atmosphere of 32,000 km. thickness,around the Earth.
COMPOSITION OF THE
ATMOSPHERE
Gas/Other
Elements
|
%
by
volume
|
Extension
Alt.in KM.s.
|
Details
|
Nitrogen
|
78.03
|
128
|
Atmospheric
pressure, force of winds and reflection of light are affected by this.
It avoids quick
burning.
It generates
protein in the plants.
|
Oxygen
|
20.99
|
16
|
It is
essential for breathing. It is the
life-giver.
It helps in
burning the fuel.
|
Carbon
Dioxide
|
00.03
|
Lower layers
|
It is the
heaviest gas.
It is
Essential for the growth of the vegetation.
It is
transparent to the incoming solar radiation and opaque to the terrestrial
radiation.
Along with
the water vapour, it is largely responsible for the greenhouse effect.
|
Hydrogen
|
00.01
|
1100
|
It is a very
light gas.
|
Ozone
|
0.000001
|
10 - 50
|
It saves the
Earth from the ultraviolet radiation of the Sun.
|
Water
vapour
|
2
|
2
|
It decreases
with the altitude.
It decreases
from the equator towards the poles.
It absorbs
the part of the insolation of the Sun.
|
Dust
Particles
|
|
|
It is the
mixture of sea salts, fine soil, ash, pollen, dust, and disintegrated
particles of the meteors. These help
the water vapour condense and form clouds.
|
STRUCTURE OF THE
ATMOSPHERE:
The Atmosphere
consists of almost concentric layers of air from bottom to its highest
limit. These layers differ from one
another with respect to density and temperature. Our atmosphere can be broadly divided into
five layers.
Name of the
Sphere/Layer
|
Extension
In K.M.s
|
Temperature
With increasing
Altitudes/height
|
Other Details
|
Troposphere
|
8 – 18
|
Decreases
@ 1oC for every 165meters.
(@ 6.4o C for every KM.)
|
Lowermost
layer of the atmosphere.
8 Kms high @
the poles.
18 Kms high
@ the equator.
Contains 90%
of the water vapour.
Temperature
@ 8 KMs: -45o C
Temperature
@ 18 KMs: -80o C
|
Stratosphere
|
Upto 50
|
Increases
|
Thicker @
poles.
Thinner @
equator.
Temperature
@ 50 KMs:0o C
Contains
Ozone gas.
Ultra-violet
rays of the Sun are absorbed here.
No clouds,
No thunderings, No lightenings, Ignorable amount of water vapours and dust
particles.
|
Mesosphere
|
50 - 80
|
Decreases
|
Temperature @ 80 KMs: -100o C
|
Ionosphere
|
80 - 400
|
Increases
|
It contains
ions. Ions are electrically charged
particles. Radio waves transmitted
from the Earth are reflected back by this layer.
Temperature
@ 400 KMs: 1000o C
|
Exosphere
|
Above 400
|
-
|
It has no
defined upper border.
It gradually
thins out until no air molecules are left in the space as the altitude
increases.
|
Air in Indian Tradition
General
properties of the Air are described by the Indians like this:
*Air is that which is colourless,and possessing
touch.
*It is of two sorts: eternal and non-eternal;
The first (eternal) is atomic and the second (non-eternal)
is a product.
*The Air is again divided into three sorts:
a) Bodyb) Organof sense c) Gross matter.
a) The airy body is in the Vayuloka,
b) The organ of senseis the organ of touch in the
shape of an airy cuticle, extending over the whole surface of our bodies.
c) Gross matter is in the form of wind that blows
andshakes the trees etc.
*Breath is the Air, moving in the interior of our
bodies.
Though it is one; it has different names accordingto
the different parts of the body it travels over andthe different functions it
performs.These are called
Pancha Pranas:
1) Prana is situated in thebreast.
2) Apana is situated in the rectum.
3) Samana is situated in the navel.
4) Udana is situated inthe throat.
5) Vyana moves over the whole body.
Traditional Hathayoga texts describe that the living
creatures survive as long as the Prana stays in the body.
Few Indian words are capable of conveying some
properties of the Atmosphere:
|
Word
|
Description
|
1
|
Dyau
Diva
|
It means something that shines.
Light makes the matter shine. Atmosphere is filled with various varieties
of gases (Air). So, it shines when the
sunlight falls.
(At night, even the unending sky shines with
various stars.)
|
2
|
Pushkara
|
It means something that gives water.
The clouds are formed in the Troposphere and give
water through rain.
|
3
|
Ambara
|
It means something where the sound travels.
The sound travels by the means of the air; through
the space.
|
4
|
Nabhas
|
It means the sky, spread beyond the presence of
the clouds.
Clouds are not seen beyond the troposphere.
So, the sky above the tropopause can be called
with this name.
|
The general term of “Vatavarana” for the modern word “Atmosphere” is well known to the general public.
However, the Indian tradition did not mention
various spheres according to the increasing/decreasing temperature or according
to the presence of various gases in the atmosphere.
Yet, Indians knew that the temperature decreases
with the increasing altitudes. Description
of hot plains and cool mountain peaks in the summer is available in the ancient
texts.
Indians knew the changes of the atmosphere in
various seasons. They knew that the Air
is neither hot nor cool by nature.
Some poets like Kalidasa recognized that, the zone
of the clouds above the earth is restricted to a particular altitude. That zone, where the clouds are formed and
where they freely move can be called as “Parjanyavarana”.
Indians knew the technique of creating clouds and
the few ancient warriors used those techniques as a weapon in the battles
against their enemies. It was called as
“Parjanya-astra”. Few other warriors could tear and terminate
that “cloud weapon” by using their “wind weapon” (Vayavya-astra). The
description of these weapons is mentioned in the Dhanurveda; a text on the
traditional weapon-science of Indians.
“Vayudeva” is the personified form the Air. He was described as a “strong Devata”. His two sons – Hanuman and Bhima - according
to the Indian mythology were very strong.
In the Bhagavata, there is an indication of
whirl-winds with the name of “Trinavarta”.
In the Ramayana, there are descriptions of some Air-crafts
such as “Pushpaka”. Kubera and Ravana
used that air craft to travel wherever they wanted to. Moreover, few Vanara-warriors
like Vali and Hanuman were apt enough to fly through the Air.
In the Ramayana again, two bird-brothers named
Sampati and Jatayu had an affable competition with each other; to fly high in
the sky. They flew to very high
altitudes. The atmosphere was very hot
there. After reaching that height,
Jatayu could not fly further and lost his consciousness. Then, Sampati spread his wings with an
intention to guard his brother from the scorching sunlight. But, unfortunately, the wings of Sampati were
totally burnt by the high temperature.
We can guess that Sampati got his wings burnt in
the Ionosphere; where the temperature unbearably increases.
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