Topic 1: Position, Behaviour And Structure Of The Earth - Physical Geography Form 5 & 6
i. Atmosphere
ii. The shape of the earth
iii. Structure of the earth
THE EARTH
The Earth is the third planet in distance from the sun and the fifth largest; The Earth is the only planet that supports life. It is distance from the Sun is approximately 149,503,000 kilometers.
CHARACTERISTICS OF THE EARTH
The Earth has the following characteristics
1. It is spherical in shape or flattened sphere (oblate spheroid)
2. It is diameter from the North Pole through the South Pole is 12,713 kilometers.
3. It is diameter from the east-west is 12,757 kilometers (at the equator).
4. The circumference of the Earth is approximately 40,000 kilometers.
5. The Earth rotates from west to east.
THE NATURE AND BEHAVIOUR OF PLANET EARTH
The planet earth is a part of large system called solar system.
The solar system is also a member of supper system called UNIVERSE and GALAXY
GALAXY
A galaxy is a large group of stars and dust held together by force of gravity.
The galaxy in our solar system found is known as Milky Way Galaxy, that contains about 200 million stars, including the sun.
The sun is one star among the many in a galaxy. All stars generated their own light hence the sun itself is star.
There are three (3) major classes of galaxies i.e Elliptical galaxies, Spiral galaxies, and Irregular galaxies.
UNIVERSE
Are the whole space and everything in it, including the earth, the planets, and the stars.
It is very large system of all system compared to solar system and galaxy. The sun with its planets and stars belongs to the system known as Galaxy, to interm a system of super system called Universe.
ORIGIN OF THE UNIVERSE
There is a controversy about the origin of the universe due to presence of various theories that explained the origin of it. However, these theories have examined processes through which the universe, galaxies, stars, and planets were found and the changes that are still taking place over time.
THEORIES ABOUT THE ORIGIN OF UNIVERSE
The following are theories postulate the origin of universe and earth in general. These are: -
i. Big Bang theory
ii. Nebular hypothesis
iii. James Jeans tidal hypothesis (Gaseous theory)
iv. Lap Lace's theory
v. Planetesimal theory
vi. Creation theory
vii. Double star theory
viii. Condensation theory
ix. Inter stellar dust hypothesis
x. Collision theory etc
TOPIC 1: POSITION, BEHAVIOUR AND STRUCTURE OF THE EARTH - PHYSICSL GEOGRAPHY FORM 5 & 6