Atmosphere of the earth
Because of the life-supporting atmosphere around our planet
Earth, there is life on Earth. No other planet or star or celestial body, as
far as the scientists up till now know, has an atmosphere like ours.
The atmosphere that surrounds the earth extends up to
hundreds of miles above us. This is almost the same all the world over.
The air that covers the earth has the same chemical
composition up to a height of about eighteen to 44 miles. This part of this layer
of the atmosphere is called the troposphere.
Beyond the troposphere is the ionosphere. This is a series of
layers, and it extends from about 44 miles to 310 miles above the earth beyond
the troposphere. This consists of particles electrified by the sun.
As we go higher beyond the ionosphere, the air becomes
thinner and thinner. The molecules in the air are constantly moving. In this
outermost layer of the atmosphere, some of the molecules escape into outer
space and never return back to the earth’s atmosphere.
The outermost layer is
called the exosphere where escaped molecules move about freely at about 400 to
about 1500 miles above the earth’s surface.
Oceanography
Our earth has more water on its surface than land. The great
oceans always fascinated man and he still has not been able to understand or
discover everything about them.
Oceanography is the study of all the science and branches
connected with the ocean to help us understand its formation, the changes that
take place in it, and all other things that happen to it.
Oceanographers study not only what happens on and around the sea, but also what is taking place inside and even down at the bottom of it. The plants and animals that live in the sea are of many types and vary in size, number and behaviour. Some experts study only this aspect of oceans.
The depth of the ocean differs at different places. Some oceanographers study this and how it affects other things and lives on
Earth. The bottom of the sea is made up of soft, oozy mud of limey skeletons of
tiny sea animals. By studying the contents of these many important facts can be
discovered.
Ocean currents are also an important part of oceanography.
The temperatures and the salt contents of the ocean are also studied by experts
for various reasons.
The tides, the regular movements of the seawater because of
the positions and pulls of the moon and the sun, are also important branches
of oceanography.
There are mountains, and volcanoes inside the sea. The levels of the land and water in some places have changed over millions of years. Indeed oceans offer great scope for scientists to study them and understand more about the planet Earth.
Reviewed by knowledge people creators
on
April 01, 2021
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